INTERNATIONAL WORKSHOP ON TROPICAL ISLAND BIODIVERSITY: ACROSS LAND AND SEA
25 – 26 September 2007
National University of Singapore

The workshop will be held at the Department of Biological Sciences Conference Room (Science Drive 4, Blk S3 Level 5). The event is free and there is no need to sign up (just come along), but please make arrangements for your own lunch - the NUS Science Canteen and canteen at Yusoff Ishak House are nearby.

This event is organized by the Department of Biological Sciences, National University of Singapore, and a group of biologists involved in the 21st Century COE Program, "Comprehensive analyses on biodiversity in coral reef and island ecosystems in Asian and Pacific regions", at the University of the Ryukyus, Japan.

The workshop will focus on the biodiversity of tropical islands and includes both terrestrial and marine environments. Attention will be given to biogeographic patterns, mechanisms influencing biodiversity, response of biodiversity to temperature change, and future directions in biodiversity research.

There will be two days of talks with four keynote speakers, 24 oral presentations, 14 poster presentations, and two roundtable discussions. The oral presentations are divided into three themes: Diversity of Marine Organisms, Diversification and Extinction of Island Animals, and Diversity and Biogeography of Island Plants.

MEMBERS OF ORGANISING COMMITTEE

Prof. Chou Loke Ming – Chairman

Prof. Peter Ng Kee Lin – Co-Chairman

Prof. Hidetoshi Ota – Co-Chairman

Prof. Euichi Hirose

Prof. Masako Izawa

Prof. Shoichiro Suda

Dr. Tetsuo Denda

*Dr. Peter Todd

*Dr. Tan Swee Hee

*Dr. Tohru Naruse

Dr. Darren Yeo Chong Jinn

*Ms. Ng Ngan Kee

Mr. Jeffrey Kwik

Mr. Tommy Tan Han Tong

* Secretariat members


 

 

PROGRAMME

 

Day 1 (25 September 2007)

 

Keynote Address -I

 

Keynote-1    9.00 – 9.40 am

Chong Ving Ching  (University of Malaya)

Coastal biodiversity of Langkawi Island: Threats and conservation
Issues

Keynote-2    9.40 – 10.20 am

Chou Loke Ming (National University of Singapore)

Marine biodiversity – here, there and everywhere

 

Break      10.20 – 10.40 am

 

Oral session -I.  Diversity of Marine Organisms

Oral -1    10.40 – 11.00 am

Masayuki Osawa (University of the Ryukyus)

Porcellanidae (Crustacea: Decapoda) of the Philippines based on the material of the Panglao Marine Biodiversity Project

 

Oral -2    11.00 – 11.20 am

Jose Christopher E. Mendoza (National University of Singapore)

Tangle net fishing in the Panglao and Balicasag Islands, a Filipino Innovation

 

Oral -3    11.20 – 11.40 am

Tohru Naruse and Ngan Kee Ng (National University of Singapore)

Taxonomy of the genus Gaetice (Decapoda: Brachyura: Varunidae) from East Asia

 

Oral -4    11.40 – 12.00 am

Ngan Kee Ng, Yukio Nakasone, and Peter K. L. Ng (National University of Singapore/University of the Ryukyus)

Ode to Y. Nakasone – Description of four species of crabs from the genus Ptychognathus Stimpson, 1858, from Okinawa, Japan (Crustacea: Decapoda: Brachyura: Varunidae)

      

Lunch     12.00 – 1.20 pm  (provided for presenters only)

 

Oral -5    1.20 – 1.40 pm

Naoko Isomura and Michio Hidaka (University of the Ryukyus)

Is gene flow rare in Isopora brueggemanni? Inference from the genetic assignment methods

 

 

Oral -6    1.40 – 2.00 pm

Tay Ywee Chieh, Peter A. Todd and Chou Loke Ming (National University of Singapore)

Modelling the transport of coral larvae within the Singapore Straits reveals potential external source reefs for the Southern Islands of Singapore

 

Oral -7    2.00 – 2.20 pm

Euichi Hirose (University of the Ryukyus)

Overview on the biogeography of photosymbiotic ascidians in Japan with new records from some islands in the Ryukyu Archipelago, Japan

 

Oral -8    2.20 – 2.40 pm

Zeehan Jaafar and Kelvin Lim (National University of Singapore)

New and interesting species of gobies from Singapore

 

Oral -9    2.40 – 3.00 pm

Shoichiro Suda and Daphne Georgina Faria (University of the Ryukyus)

Overview of the genus Nephroselmis from the Ryukyu Islands (Chlorophyta, Nephroselmidales)

Break     3.00 – 3.20 pm

 

Oral Session-II. Diversification and Extinction of Island Animals

 

Oral -10    3.20 – 3.40 pm

Masako Izawa and Nozomi Nakanishi (University of the Ryukyus)

Factors affecting the current diversity and distribution of mammals in the Ryukyu Archipelago, Japan

 

Oral -11    3.40 – 4.00 pm

Tzi Ming Leong (National University of Singapore)

Taxonomic importance of a tiny island: type locality - Singapore. New species from inland to off-shore. Will we discover more?

 

Oral -12    4.00 – 4.20 pm

Nozomi Nakanishi and Masako Izawa (University of the Ryukyus)

Significance of diversity of small animals as viewed from a wild cat surviving on a small subtropical island

 

Break       4.20 – 4.40 pm

 

Round-table discussion -1     4.40 – 5.30 pm

Chairman: Euichi Hirose (University of the Ryukyus)

Co-Chairman: Tan Swee Hee (National University of Singapore)

What shall we do about rarely studied taxa that include numerous undescribed common species?  


Day 2 (26 September 2007)

 

 

Keynote Address - II

 

Keynote -3    9.00 – 9.40 am

Makoto Tsuchiya (University of the Ryukyus)

Ecology of coral associated animals: Habitat island and species diversity

 

Keynote -4    9.40 – 10.20 am

Navjot Sodhi (National University of Singapore)

Southeast Asian biodiversity in crisis

 

Break   10.20 – 10.40 am

Oral Session-II. Diversification and Extinction of Island Animals

(extended)

 

Oral -13    10.40 – 11.00 am

Ryo Fujii (University of the Ryukyus)

Current chelonian diversity of the East Asian islands

 

Oral -14    11.00 – 11.20 am

Thor-Seng Liew (University Malaysia Sabah)

Biogeography and evolutionary patterns of landsnails on the island of Borneo

 

Oral -15    11.20 – 11.40 am

Akio Takahashi (University of the Ryukyus)

Fossils of terrestrial turtles indicate the Late Pleistocene mass extinction in the East Asian Islands

 

Oral -16    11.40 – 12.00 am 

Tadahiro Ikeda (University of the Ryukyus)

The Late Pleistocene snakes fauna (Reptilia: Squamata) of the Ryukyu Archipelago, Japan, as inferred from recently discovered fossils

 

Lunch   12.00 – 1.20 pm (provided for presenters only)

 

Oral -17    1.20 – 1.40 pm

Norman Lim (National University of Singapore)

Cynocephalus variegatus (Dermoptera) and Manis javanica (Pholidota): examples of neglected mammalian orders

Oral -18    1.40 – 2.00 pm

Yasuyuki Nakamura (University of the Ryukyus)

The Late Pleistocene-Holocene changes in the distribution and body size of amphibians on Okinawajima Island, the Ryukyu Archipelago, Japan

 

Oral -19    2.00 – 2.20 pm

Tan Heok Hui (National University of Singapore)

The unique biodiversity of Pulau Tioman, Malaysia

 

Break       2.20 – 2.40 pm

 

Oral Session-III. Diversity and Biogeography of Island Plants

 

Oral -20    2.40 – 3.00 pm

Koh Nakamura, Tetsuo Denda, and Masatsugu Yokota (University of the Ryukyus)

Plant distribution patterns in the Ryukyu Archipelago, Japan, in the light of seed dispersal abilities

 

Oral -21    3.00 – 3.20 pm

Look Su Lee (National University of Singapore)

Population genetics of the Joey palms, Johannesteijsmannia H.E.Moore (Palmae)

 

Oral -22    3.20 – 3.40 pm

Testuo Denda (University of the Ryukyus)

Cytological diversity of the genus Hydrangea (Saxifragaceae) in the Ryukyu Arcipelago, Japan – On the origin of the tetraploidf Hydrangea liuliuensis endemic to Okinawajima Island

Oral -23    3.40 – 4.00 pm

Shawn Lum  (National Institute of Education, Singapore)

CTFS and the Bukit Timah Project

 

Oral -24    4.00 – 4.20 pm

Benito Tan (NParks, Singapore/ National University of Singapore)

Biodiversity and conservation of non-vascular plants in Asia - what lessons can we learn from mosses?

Break    4.20 – 4.40 pm

Round-table discussion -2    4.40 – 5.30 pm

Chairman: Peter Ng (National University of Singapore)

Co-Chairman: Hidetoshi Ota (University of the Ryukyus)

Barcoding will solve the taxonomic impediment

Note: All meetings will be held in the Conference Room, Department of Biological Sciences, National University of Singapore

 

Poster Session

 

Poster -1

Aki Katoh, Masasuke Baba, and Shoichiro Suda (University of the Ryukyus/Marine Ecology Research Institute)

A systematic study of crustose coralline algae (Corallinales, Rhodophyta) in the Ryukyu Islands

 

Poster -2

Jeff T.B. Kwik, T. M. Sin, and Peter K. L. Ng (National University of Singapore/ Tropical Marine Science Institute, Singapore)

Species diversity and potential growth rates of common scorpaenids found in coastal Singapore shores


Poster -3

Joelle C. Y. Lai and Peter F. Davie (National University of Singapore/Queensland Museum, Australia) 

The union of barcoding and taxonomy: A case study in the commercially valuable blue swimming crab, Portunus pelagicus species complex


Poster -4

Daniel Edison M. Husana, Tomoki Kase, and Tohru Naruse (University of Tokyo/National University of Singapore)

A new cavernicolous freshwater crabs from Samar, Island, Philippines

 

Poster -5

Huang Danwei, K. P. P. Tun, and L. M. Chou (National University of Singapore)

Updating records of zooxanthellate scleractinian corals in Singapore

 

Poster -6

Hidetoshi Ota (University of the Ryukyus)

History of taxonomic recognition of reptile diversity in the East Asian Islands

 

Poster -7

Myron Shekelle (National University of Singapore)

Taxonomy, biogeography, and conservation of tarsiers

 

Poster -8

David Bickford (National University of Singapore)

Cryptic species: What we donŐt know might hurt us

 

Poster -9

Adrian L. Lim and Daiqin Li (National University of Singapore)

Text Box: Insular biogeography of web-building spiders on small tropical islands surrounding Singapore

 

Poster -10

Hwang Wei Song (National University of Singapore)

Resolving species limits within Dicranosepsis

Poster -11

Reuben Clements (National University of Singapore)

Biogeographical patterns of molluscs on tropical limestone karst ÔislandsŐ

 


Poster -12

H. Zettel and A.D. Tran (Natural History Museum Vienna, Austria/ National University of Singapore)

First inventory of the aquatic and semi-aquatic bugs (Heteroptera: Nepomorpha & Gerromorpha) of Langkawi Island, West Malaysia

 

Poster -13

S. M. Feroz, Akio Hagihara, and Masatsugu Yokota (University of the Ryukyus)

Comparative studies on woody species diversity and structure in subtropical evergreen broadleaf forests along a latitudinal thermal gradient of the Ryukyu Archipelago

 

Poster -14

James Davis Reimer (University of the Ryukyus)

Preliminary examination of zooxanthellate zoanthid (Hexacorallia, Zoantharia) and associated zooxanthellae (Symbiodinium spp.) diversity in Singapore

 


ABSTRACTS

 

Keynote -1

 

Coastal biodiversity of Langkawi Island: Threats and conservation issues

Chong Ving Ching

Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia

 

Of the 104 islands in the Langkawi archipelago situated at the northwestern corner of peninsular Malaysia, Langkawi Island is the largest with an area of 526 sq km.  In the last two decades, this large island has been experiencing a development boom through governmental efforts to promote it as an international tourism destination.  Langkawi Island  was first  conferred  free port status in 1987, and recently, the Kedah Maju Master Plan 2010 has designed the island as the Western tourist corridor of Kedah.  The number of tourists has dramatically increased from just 200,000 in 1986 to 2 billion in 2003.   In fact, tourism has dramatically transformed the socio-economy of the island; the once dominant agro-fisheries sector has now declined by 50% as the local populace activities increasing cater to the more lucrative tourism industry.   There is growing concern that the boon and development may have damaged some of the islandŐs unique coastal biodiversity.  The northeast Langkawi region (NEL) is of particular interest, because it is as yet relatively unmarred by development , and forms an unique wetland complex containing several marine and estuarine systems including  coral reefs, mangroves, river basins, lagoons, sandy-rocky shores, limestone karsts and lowland forests.  NEL is underlain by the Lower Palaeozoic Setul Limestone Formation, rich in Ordovician and Silurian fossil remains, and bearing artifacts of early Holocene human settlement.  Among the extant rich flora and fauna are the distinctive, rare, first or new records of cycads, orchids, bryophytes, lichens, seaweeds, fish, crabs, beetles and amphibians.  This paper discusses the findings of two recent scientific expeditions to Langkawi Island, the first in April 2003 and the second in April 2004, particularly on the coastal biodiversity of NEL, the threats to its rich diversity, and justification for its conservation. 

 

Keynote -2

 

Marine biodiversity - here, there and everywhere

 

Chou Loke Ming

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

The extent and depth of the marine environment presents a great challenge to the study of its biodiversity. Logistic difficulties and financial requirements are greater and we are still far from a comprehensive inventory of marine species richness. Limited exploration of the oceanic depths revealed many previously unknown but interesting species including habitats driven by chemical energy. Although shallow seas have been investigated much more, new species discoveries are still being made. In some cases, species new to science have been known to locals but escaped the attention of scientists. A good example is the coelacanth from Manado. In other cases, scientists target pristine or remote areas to discover new species, an example of this being Bird's Head Seascape in Indonesia's Papua province. Non-pristine areas subjected to long-term human impacts have also shown to harbour species that have escaped detection until recently. Such examples indicate that studies on marine biodiversity even in highly impacted areas are needed for the development of reliable inventories. Marine biodiversity is everywhere if one cares to look for it.  

 

Keynote -3

 

Ecology of coral associated animals: Habitat island and species diversity

 

Makoto Tsuchiya

 

Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

Closely related taxa demonstrating niche overlap may show marked species interactions as they compete for resources, or show resource partitioning and character displacement. The diverse organisms of coral reefs interact in intricate ways, among which ecology of small animals associated with branching corals has been well studied. The resource limited system of a coral colony for its associated animals is an appropriate system for the study of community organizing processes or is a good tool for discussing the concept of island ecology as a habitat island.

            In colonies of pocilloporid and acroporid corals, several obligate symbionts such as xanthid crabs, Trapezia spp. and Tetralia spp., a snapping shrimp, Alpheus lottini, and gobioid fishes, Paragobiodon spp, occupy limited resources. Because these species show similar characteristics of microhabitat, diet, and behavior, they are considered to be potential competitors, and their intra- and interspecific interactions must be interesting research topics. Since several species may be able to coexist within a large coral colony and underwater and laboratory observations of Pocillopora damicornis colonies have not revealed habitat segregation among different species of Trapezia adults on a colony, detailed analyses of the mechanisms of their coexistence are needed.

            Species composition of Trapezia spp. associated with Pocillopora damicornis were analyzed for several populations collected at seven localities, i.e. Ushibuka (Kumamoto Prefecture), Sesoko, Itoman (Okinawa Island), and Shiraho (Ishigaki Island) in Japan, and Sichang, Samui, and Phuket in Thailand. One of the most conspicuous phenomena was found for the Sichang population of Trapezia cymodoce from the inner part of the Gulf of Thailand. This was the only species of Trapezia collected among the branches of P. damicornis, and specimens of this species were larger in comparison to those collected from other localities. This phenomenon was also observed off Samui in the Gulf of Thailand. In the localities surveyed, Trapezia were usually larger in size in larger coral colonies; however, different patterns in the relationship between colony size and crab size were observed, especially when small specimens occurred in conjunction with heterosexual pairs in a colony. The pattern in populations of T. cymodoce at Sichang was quite conspicuous and differed from those observed at other coral reefs. Only one heterosexual pair was collected even on the large colonies of P. damicornis.

            It is well known that, if the starfish Acanthaster planci attacks the crabŐs host coral, P. damicornis, the crab will attempt to expel the starfish by snipping at its spines or tube feet. When we compared sizes among 10 large specimens of each species, T. cymodoce, T. digitalis, and Trapezia lutea, those specimens found in the presence of A. planci were significantly smaller than in its absence (t-test, P < 0.05). No A. planci have been found in Sichang.

We can therefore hypothesize about the coexistence of closely related Trapezia spp. on a large colony. The coral-eating starfish A. planci is an important force in controlling population traits and species composition of the obligate coral symbiont Trapezia. When a large population of A. planci forms at a coral reef, the crabs must protect their host corals from aggression by these starfish. In such situations, Trapezia species have no time to compete with each other; instead, they coexist on a colony because they must protect their host coral from a common enemy, A. planci.

            In the summer of 1998, when mass coral bleaching occurred, the relationship between Trapezia and its host coral P. damicornis was investigated. Although six species of Trapezia were collected during this survey, bleached colonies harbored fewer individuals and species of obligate symbionts than unbleached colonies before the bleaching event. Even on the larger colonies, of which the volume of the interbranch space was considered to be enough for harboring several specimens of Trapezia, no obligate symbionts were found. Heterosexual pairs of symbionts such as Trapezia spp., Alpheus lottini, and Paragobiodon spp. were rather uncommon, and the abundance of ovigerous females of Trapezia was lower and clutch sizes were smaller than usual.

            These four species or groups, i.e. coral, zooxanthellae, Trapezia, and Acanthaster, have coevolved together, and the extinction of one species would seriously disturb their interactive relationships. The relationships among them are discussed from the view point of biodiversity and species interactions.

 

 

Keynote -4

 

Southeast Asian biodiversity in crisis

 

Navjot Sodhi

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

The biodiversity of Southeast Asia is gravely imperiled by drivers including massive habitat modifications, forest fires and the overexploitation of wildlife. I will present on a comprehensive determination of the current state of Southeast AsiaŐs terrestrial biotas and highlight the primary drivers responsible for the grave threat to the regionŐs unique and rich biodiversity. The looming Southeast Asian biodiversity disaster demands tangible actions. However, such will continue to be constrained by socioeconomic variables (e.g. rampant poverty and lack of infrastructure). Any realistic solution should involve a multi-pronged strategy (e.g. political, socioeconomic and scientific) in which all major stakeholders (e.g. people, governments, and national and international non-government organizations) must partake.

 

 

Oral -1

 

Porcellanidae (Crustacea: Decapoda) of the Philippines based on the material

 of the Panglao Marine Biodiversity Project

 

Masayuki Osawa

 

Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

The crab-shaped anomuran family Porcellanidae (Crustacea: Decapoda) includes approximately 30 genera and 280 species mainly distributed in the temperate to tropical waters of the world. Among them, 18 genera and 125 species are presently known from the Indo-West Pacific. The crabs occur at depths above the continental shelf (< 200 m), but are most abundant in the intertidal region on rocky and coral reefs. Many intertidal species (e.g., the genera Petrolisthes, Pahchycheles) live in narrow spaces between rocks or dead coral blocks, whereas shallow subtidal species (e.g., Lissoporcellana, Polyonyx) are occasionally found in association with sponges and a variety of alcyonacean octcorals (soft corals). The porcellanids are known to be typically suspension feeders and catch food by using the external mouthparts (third maxillipeds) bearing long plumose setae. 

The Panglao Marine Biodiversity Project 2004 (PANGLAO 2004), an international research of coastal fauna mainly on crustaceans and mollusks, was conducted around the island of Panglao located southwest off Bohol, the Philippines. During this research project, abundant material was obtained by trawling, dredging, coral brushing, intertidal sampling, sea bottom suctioning, diving, traps and traditional fishing methods such as tangle nets. 

Approximately 660 porcellanid specimens were collected from the intertidal region to 150 m depth through the PANGLAO 2004. They contain at least 25 species of nine genena such as Aliaporcellana, Enosteoides, Heteropolyonyx, Lissoporcellana, Neopetrolisthes, Pachycheles, Petrolisthes, Pisidia, and Polyonyx. Enesteoides and Polyonyx include some undescribed species, and the latter genus comprises seven species at least and is highest in species number. Individuals of Petrolisthes militaris and P. scabriculus are abundant in this material. The two species have been frequently recorded from depths of more than 20 m unlike most of other congeners are intertidal dwellers. Although 19 species and ten genera were previously known from the Philippines, the PANGLAO material lacks six species and three genera (Capilliporcellana, Novorostrum, and Porcellanella). 

In Indonesian waters adjacent to the Philippines, 11 genera and 33 species have been hitherto reported. From the Ryukyu Islands in the southwestern Japan, nine genera and approximately 40 species have been found and most of them are collected from the intertidal region to 2 m depth. The porcellanid fauna of New Caledonia and the Loyalty Islands, southwestern Pacific, was also recently documented, and it comprises 11 genera and 36 species including three new species. A new species, Polyonyx spina, was described on the basis of the material of the Loyalty Islands and the PANGLAO 2004. The species recorded from the Philippines are generally found in those from Indonesia and the southwestern and northwestern Pacific islands. However, the numbers of Petrolisthes species are much fewer in the Philippine material than those of other three areas. This is probably due to limited sampling efforts in the intertidal region through the PANGLAO 2004. Further research may eventually reveal existences of more intertidal species as well as shallow subtidal species hiding in crevices of coral reefs. 

The porcellanids occurring in the tropical and subtropical waters are generally known to have wide distributions in the western Pacific or Indo-West Pacific, although their occurrence records are frequently scattered and taxonomy of some species seems to remain unclear. Mud and fine sand substrata in the estuaries and mangroves are generally regarded as unusual habitat for porcellanids. However, some species of Petrolisthes can be obtained from hard objects on such soft substrata, and some Polyonyx and Raphidopus species are also known to be associated with tube-dwelling polychaetes as infaunal burrows. Further special effort to obtain estuarine species will have to be made for understanding of the true fauna of porcellanids in Southeast Asia since many estuaries, mangrove swamps, and similar environments exist there.  

 

 

Oral -2

 

Tangle net fishing in the Panglao and Balicasag Islands, a Filipino innovation

 

Jose Christopher E. Mendoza

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Tangle nets have been in use by the fishermen of Panglao and Balicasag Islands in the central Philippines for decades. This indigenous fishing method is primarily designed for catching benthic marine life, particularly mollusks and crustaceans, for food and the collectorsŐ trade. The nets are made of light synthetic netting material, with a mesh size of about 1 inch square, and suspended on 5-mm thick nylon ropes on both edges. The dimensions of a single, rectangular net are usually 1-1.5 m in width and between 100-200 m in length. Small lead weights are attached on the lower edge of the net. The effective depths at which these nets are used range from 30-200 m. To deploy the net, one end is weighed down by rocks, which serve as a makeshift anchor, tied to the nylon rope. The rest of the net is lowered using a spool-like mechanism as the fishermanŐs boat moves along a line projected by the fisherman. The other end (usually found in shallower depths) is tied to a large buoy, which marks the position of the net and aids in the location and retrieval of the net. The net then settles on the seabed and is left there overnight or for about 24-48 hours. As crustaceans and mollusks crawl over it they get entangled and caught in the meshwork. The fisherman then retrieves the net by diving into the water to get the end attached to the buoy, and fitting this end into the spool. The fisherman then commences to pull the net up by means of the spool, sometimes doing some skillful maneuvering to untangle the net if it gets snagged in the irregular underwater terrain. Any specimens caught in the net are then carefully disentangled, such that most of the time they are in better condition than specimens brought up by trawl or dredge. In recent years, tangle net fishing has yielded astounding and rare biological finds, including several new taxa. Tangle net fishing has also been shown to efficiently collect specimens from areas that cannot be sampled using traditional methods such as trawls and dredges.


 

Oral -3

 

Taxonomy of the genus Gaetice (Decapoda: Brachyura: Varunidae) from East Asia

 

Tohru Naruse and Ngan Kee Ng

 

Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore

 

Taxonomy of the intertidal crab genus Gaetice is reviewed. The genus currently contains 2 species from East Asia, G. depressus and G. ungulatus. Gaetice depressus has been known to occur from Honshu to Kyushu and Ryukyu Islands in Japan, Taiwan, Korea, and from southeastern to southern China. Our studies, however, have shown that populations from Iriomote Island and Okinawa Islands are morphologically different from those of other populations, and as such, we recognize these populations as an undescribed species. Stimpson (1858) recorded G. depressus and G. convexiusuculus from the Loo Choo (=Ryukyu Islands). His ŇG. depressusÓ from the Ryukyus is most probably the undescribed species mentioned above. Gaetice convexiusuculus has been synonimized under G. depressus since Sakai (1939). Our reexamination of G. ungulatus, however, revealed that the morphology of G. ungulatus agree well with that of G. convexiusuculus. As such, we propose to resurrect G. convexiusuculus and synonimize G. ungulatus under G. convexiusuculus. We also describe one new species from Qingdao, China. In summary, we recognize four species from East Asia: G. depressus from Honshu to Kyushu in Japan, Taiwan, Korea, and from southeastern to southern China; G. sp. 1 from Okinawa Island and Iriomote Island; G. convexiusuculus from Okinawa Island and Iriomote Island; G. sp. 2 from Qingdao, China.

 

 

Oral -4

 

Ode to Y. Nakasone – Description of four species of crabs from the genus Ptychognathus Stimpson, 1858, from Okinawa, Japan

(Crustacea: Decapoda: Brachyura: Varunidae)

 

Ngan Kee Ng1, Yukio Nakasone2, and Peter K. L. Ng1

 

1Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore, and 2College of Education, University of Ryukyus, Nishihara, Okinawa 903-01, Japan

 

Four new species of varunine crab of the genus Ptychognthus Stimpson, 1858, are described from Okinawa, Japan. Currently, there are seven species of Ptychognathus found throughout Japan viz. P. glaber Stimpson, 1858, P. barbatus (A. Milne Edwards, 1873), P. ishii Sakai, 1939, P. takahashii Sakai, 1939, P. hachijoensis Sakai, 1955, P. capillidigitatus Takeda, 1984, and P. insolitus Osawa & Ng, 2006. Recently, fresh Ptychognathus species were collected from several rivers on Okinawa Island, Ryukyus, Japan by Dr. Y. Nakasone. Among them were three known species viz P. barbatus (A. Milne Edwards, 1873), P. ishii Sakai, 1939, and P. capillidigitatatus Takeda, 1984, and four new species. The four new species are different from the currently known Ptychognathus species in the forms of the carapace, cheliped, ambulatory leg, abdomen, male gonopod, and female gonopore, which indicate that they should be referred as new. The number of Ptychognathus species found in Japan, hence, increases from seven to eleven species, with a majority of them found mainly in the Okinawa Islands.

 

 


Oral -5

 

Is gene flow rare in Isopora brueggemanni? – Inference from

 the genetic assignment methods

 

Naoko Isomura1 and Michio Hidaka2

 

1Graduate School of Engineering and Science, and 2Department of Chemistry, Biology and Marine Science, University of the Ryukyus

 

The scleractinian coral Isopora brueggemanni, which is distributed throughout the Ryukyu Archipelago (Okinawa Island, Miyako Island, and the Yaeyama Islands), is a hermaphroditic brooder. However, only a few planulae were released intermittently from colonies kept in running seawater tanks and no apparent periodicity of planula release was observed. Histological study suggests that some planulae might be produced through self-fertilization. Although this coral forms colonies with short stout branches, asexual reproduction via fragmentation occurs frequently under natural conditions.

            Our previous study showed that the clonal structure and genetic diversity of each population of I. brueggemanni were very different, and that there was significant genetic differentiation among the populations. This is probably because gene flow via planulae dispersion is low due to low dispersal capacity of planulae or to predominance of asexual reproduction via fragmentation.      

            In this study, to estimate the extent of gene flow (connectivity) among populations of I. brueggemanni, we performed genetic assignment methods to detect migration over far shorter timescales using microsatellite markers.

            We sampled I. brueggemanni from 19 populations at three sites in the Ryukyu Archipelago (three from the Kerama Islands, three from Miyako Island, three from Ishigaki Island, and ten from Sekisei Lagoon). A total of 313 colonies were genotyped using four microsatellite markers, IbTC2, IbTC13, IbAAT6 and IbAAT12. The number of genetically differentiated I. brueggemanni populations, K, was estimated by employing a Bayesian approach, implemented in the program Structure (Pritchard et al. 2000). F0 immigrants in populations were estimated by employing a Monte Carlo resampling method, implemented in the program GeneClass 2 (Piry et al. 2004) using data of genotyping.

            The result of the genetic assignment methods indicated that there were very few numbers of immigrants at all sites (Kerama Islands; 3, Miyako Island; 4, Sekisei Lagoon; 17). Most populations were constructed by original members of the populations and most of the immigrants at Kerama Islands and Miyako Island have originated from Sekisei Lagoon. Although three populations of Kerama Islands were very close to each other, no immigrants originated from the neighboring populations were detected. The low number of immigrants among populations and maintenance of each population by its original members might be due to the unique mode of reproduction of the coral, though the direction of Kuroshio Current may also contributed to the isolation of the populations.

 

 

Oral -6

 

Modeling the transport of coral larvae within the Singapore Straits reveals potential external source reefs for the Southern Islands of Singapore

 

Tay Ywee Chieh, Peter A. Todd, and Chou Loke Ming

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

SingaporeŐs coral reefs have experienced significant anthropogenic impacts for at least three decades, mostly resulting from land reclamation activities. Nevertheless, the species richness of scleractinian coral communities around the Southern Islands is comparable to other more extensive reefs in the region. Little has been done, however, to protect the remainder of these reefs, which support a diverse array of marine life. Ongoing reef restoration efforts that are labour and cost-intensive may not be sustainable in the long run if there is no natural recruitment to replenish the populations. The nature of the marine environment provides many opportunities for exchange of genetic material between conspecifics of different populations, this is especially true for broadcast spawners such as most scleractinian corals. Knowledge of the intricate processes of reef dynamics and connectivity, which can be identified using hydrodynamic-advection and individual-based models, is important for reef management decisions.

A two-dimensional hydrodynamic, flexible mesh model (MIKE 21) coupled with a Lagrangian particle tracking module was used to simulate larvae distribution within the Singapore Straits and the South Channel after known coral mass spawning events in Singapore, and predicted spawn times on the northern coasts of Pulau Batam and Pulau Bintan in Indonesia. In each simulation, neutrally buoyant, passive particles representing the generally passive coral planulae were released during the mass spawn times in years 2003, 2005 and 2007. Findings indicate that most of the coral larvae released from Singapore are carried away during the peak settlement competency periods, and therefore do not contribute to seeding the local reefs, while larvae from Pulau Batam are brought towards Singapore. This means that, in order to effectively protect SingaporeŐs reefs, conservation strategies need consider external source reefs which may necessitate reef management collaborations with Indonesia.

 

 

Oral -7

 

Overview on the biogeography of photosymbiotic ascidians in Japan with new records from some islands in the Ryukyu Archipelago, Japan

 

Euichi Hirose

 

Department of Chemistry, Biology and Marine Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-0213, Japan

 

Obligate photosymbioses have been known in some colonial ascidians of the family Didemnidae. The photosymbionts are always prokaryotic algae; Prochloron in many of the host species, Synechocystis in some Trididemnum spp., and/or unknown cyanophytes. The host ascidians are exclusively distributed in tropical and subtropical waters, probably due to the susceptibility to low temperature of the photosymbionts. Recently, we started the biogeographic survey of the photosymbiotic didemnids in the Ryukyus to record the current status of their distribution, because they would be potential indicators for the increase of seawater temperature due to the global warming.

In the 20th century, only five photosymbiotic species were recognized mainly in the Ryukyu Archipelago, probably because not many taxonomical surveys had been carried out in Japan. To date, we surveyed the distribution of the photosymbiotic ascidians in the several continental islands belonging to the Ryukyu Archipelago and Chichijima Island, an oceanic island, belonging to the Bonin Island, and 15 or more photosymbiotic species are so far known to be distributed in Japan. In the present study, we reported the new records of the photosymbiotic ascidians from Miyakojima Is., Kurimajima Is., Kumejima Is, Yakushima Is., and Tanegashima Is., and reviewed the biogeography and taxonomy of the photosymbiotic didemnids in the Ryukyus.

Species #

(Undescribed

species #)

 
In the Ryukyu Archipelago ranging from about 24ĽN to 31ĽN, the species number of the photosymbiotic species tended to be larger in the islands of lower latitude, and gradually decreased toward north: 15 species and three potentially undescribed species were recorded from Yaeyama Islands, the south-most island group in the Ryukyus, as three species and one undescribed species were recorded from Oh-sumi Islands, the north-most island group. Therefore, for many photosymbiotic species, the north limit of the distribution range lies within the archipelago, suggesting that the photosymbiotic didemnids can be a potential indicator for the warming of seawater. On the other hand, only 4 species were recorded from Chichijima Island, whereas the latitude is rather lower than that of Amamiohshima Island where 10 species were recorded. It would have been difficult for the ascidian larvae to reach the oceanic islands from other areas, causing the fewer numbers of the photosymbiotic species. The survey should be extended to the mainland of Japan in future study.

We described two photosymbiotic Diplosoma species as new species in 2005: D. ooru Hiroe et Suetsugu and D. simileguwa Oka et Hirose. Later, the two species were respectively recorded in Palau and Heron Is. (GBR), and thus, they are supposed to be widely distributed at least in tropical West Pacific. This may indicate that many unknown species are yet to be described in tropics, and we recognized other three Diplosoma that are potentially undescribed species. The three Diplosoma species can be distinguishable with the unique pattern of the stigmatal numbers in the branchial sac. For instance, the stigmatal numbers are 6, 7, 6, and 5 from the top row to the bottom in one species. As for the three species, we unfortunately have not obtained the colonies laden embryos that would provide several taxonomical features. On the other hand, some described species should be carefully examined, because there are some arguments about synonyms; Lissoclinum bistratum –L. timorense, Trididemnum cyclops – T. paracyclops, and Trididemnum clinides – T. paraclinides. There are several color-morph types and size-morph types in Didemnum molle, and we found differences in the contents of ultraviolet-absorbing substances, reproductive season, and commensal crustacean fauna between the two color-morph types, suggesting that this species may include one or several cryptic species. A taxonomic survey based on both detailed morphology and the molecular phylogeny of several potential synonyms or morph types from various sites is required to clarify this problem.

 

 

Oral -8

 

New and interesting species of gobies from Singapore

 

Zeehan Jaafar and Kelvin Lim

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

The family Gobiidae comprises of some 2000 small teleost fishes commonly known as gobies. A recent faunistic survey of this group carried out in Singapore revealed that there are 149 species with about a quarter of them not recently found or reported from the island. The presentation discusses these dubious records and presents new and interesting finds.

 

 

Oral -9

 

Overview of the genus Nephroselmis from the Ryukyu Islands

 (Chlorophyta, Nephroselmidales)

 

Shoichiro Suda1 and Daphne Georgina Faria2

 

1Department of Chemistry, Biology and Marine Science, Faculty of Science, and 2Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

Nephroselmis is a green flagellate genus and was established by Stein in 1878 based on a freshwater species, N. olivacea. It possesses compressed cells in the right-left axis, two unequal and heterodynamic flagella, and simple to complex scales forming the Golgi body covering the surface of body and flagella. The SSU rDNA tree suggests that the family Nephroselmidaceae, which contains only the type genus Nephroselmis, is closely related to the core chlorophytes (Chlorophyceae + Trebouxiophyceae + Ulvophyceae + Chlorodendrales). The genus Nephroselmis is therefore a key organism in the evolution of the Chlorophyta sensu stricto and the origin of the major part of green algae. Phylogenetic studies on various species of Nephroselmis using morphological and molecular characters are therefore important. At present, 12 Nephroselmis species have been described but for five out of the 12 species there is very limited information and their existence as valid species is doubtful. Aside from one freshwater species, the remaining six species have been reported from marine environments. Nephroselmis swims with the short flagellum beating ahead and a long flagellum trailing behind. Because of its unique swimming behavior, Nephroselmis cells can be easily identified and isolated under an inverted microscope in samples, and was collected from various localities of the Ryukyu Islands. Over five years, our laboratory established 122 strains of Nephroselmis. Consequently, the strains could be divided into eight morphological groups. Four groups are likely to correspond to four known species, N. olivacea, N. anterostigmatica, N. astigmatica and N. pyriformis. The remaining four groups may contain N. gaoae, N. minuta, N. rotunda or new taxa but detailed ultrastructural observations are needed to identify these groups conclusively. To help achieve this, some strains were subjected to TEM observations, pigment analyses and molecular phylogenetic analyses. Morphologically, three potentially undescribed groups are designated here as three undescribed species, sp. 1 to sp. 3. The molecular phylogenetic analysis of 18S rDNA sequences revealed that the three undescribed species were distributed in a monophyletic genus Nephroselmis. The genus was divided into four monophyletic clades (A to D) and each clade was supported by relatively high bootstrap values. In addition, pigment compositions of carotenoids and xanthophylls were somewhat related with molecular phylogeny of the genus Nephroselmis. The rest of the collected strains from the Ryukyu Islands may also contain previously unrecorded known or unknown species, and further characterizations are needed. In this paper we present an overview of some of our work on the unique genus Nephroselmis.

 

 

Oral -10

 

Factors affecting the current diversity and distributions of mammals

in the Ryukyu Archipelago, Japan

 

Masako Izawa1 and Nozomi Nakanishi2

 

1Laboratory of Ecology and Systematics, and 2The 21st Century COE Researcher, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

The Ryukyu Archipelago lies between Kyushu of Japan and Taiwan, and consists of more than 150 islands. The northern tip of this archipelago belongs to the temperate zone, whereas the remainder to the subtropical zone. Within the Ryukyu Archipelago, following eight island assemblages are usually recognized—Osumi Group, Tokara Group, Amami Group, Okinawa Group, Miyako Group, Yaeyama Group, Senkaku Group, and Daito Group. Components of the first six assemblages form an island chain from northeast to southwest and are separated from the continent by East China Sea. The Senkaku Group is located on the continental shelf north of the Yaeyama Group, whereas the Daito Group, the only representative of oceanic islands in this region, are located ca. 360 km east of the Okinawa Group. The Tokara Group is further divided into two parts, the northern and southern Tokara islands, by the Tokara Tectonic Strait, which is often considered as a border between the Palearctic and the Oriental zoogeographical realms, being referred to as the Watase's Line. The Kerama Gap, located between the Okinawa Group and the Miyako Group, is often considered as another important biogeographical border under the reference name, the HachisukaŐs Line.

The fauna of the Ryukyus is generally characterized by high lineage diversity and remarkable endemicity as a whole, and distinct population divergence in many lineages among islands and island assemblages. These faunal characteristics are usually attributed to the complicated geological history of this archipelago. We review mammal fauna of the Ryukyu Archipelago and discuss geographical features of its diversity by considering not only the paleogeographical process of this archipelago, but also ecological properties of this group of organisms and insular environments. We try to make best use of the results from most recent studies, although quite a few taxa obviously need further evaluation for their taxonomic status (e.g., the Iriomote cat), or indigenousness of the Ryukyu populations (e.g., house mouse), or actual occurrence in this region (e.g., various forest-dwelling bats).  

A total of 35 putatively indigenous species of terrestrial mammals are known from the Ryukyu Archipelago. Distributions of these species can be classified to several types. From a viewpoint of endemism, for example, five species are confined to single islands and four to single island groups, whereas five species are shared by two or more island groups and one by the Ryukyu Archipelago and Taiwan. The remaining 20 species are widely distributed, although six of them are still endemic to Japan, and many of the remainder need further taxonomic studies and distribution surveys (see above).

We chiefly discuss three biogeographical features of mammals of the Ryukyu Archipelago.

1) Scarcity and range limitation of medium- and large-bodied mammals in this region. This seems to be related to various biotic and abiotic environmental factors, such as habitat diversity and community structure on each island. Small area and low altitude of most Ryukyu islands, obviously reflecting their low habitat diversity and simple community structure, are likely to be strictly limiting the chance for such mammals to establish populations there, unless they acquire certain ecological specializations as exemplified by the Iriomote cat (see Oral-12). Consequent vacancy of some niches in the Ryukyu islands seems to have enabled other animals to make their niches unusually broad.

2) Distinct patterning in geographic distributions of non-volant mammals in this region. Most of their ranges are delimited by the WataseŐs Line and the HachisukaŐs Line (see above), as has been already noted. This suggests the substantial influence of paleogeography on the formation of current distributions of species and subspecies in mammals as in the case of other animal groups.

3) Unexpectedly limited distributions of chiropteran species and subspecies in this region. Many previous authors implicitly or explicitly assumed that bat taxa generally show distributions whose pattern does not necessarily correspond to island configulation due to their highly effective migration ability. However, many of the Ryukyu bats actually show strongly limited distributions that more or less correspond to island shapes. This probably reflects the influence of geographic arrangements of important resources, such as resting sites and foraging areas.

 

 

O-11

 

Taxonomic importance of a tiny island: type locality - Singapore. New species from inland to off-shore. Will we discover more?

 

Tzi Ming Leong

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

The island of Singapore has been the designated type locality for practically hundreds of newly described taxa for more than a hundred years. New genera, subgenera, species and subspecies of a wide variety of vertebrates and invertebrates have been described by various scientists from around the world, even till today. In total, how many published taxa have been described. Of these, how many are actually valid still? In the future, how many more discoveries remain to be unearthed? Where are some of the local 'hotspots' for biodiversity, where potentially new species lie waiting to be found? This is a preliminary attempt to answer these, and other questions, pertaining to Singapore's past, present and future significance from a taxonomic perspective.

 

 

Oral -12

 

Significance of diversity of small animals as viewed from a wild cat surviving

 on a small subtropical island

 

Nozomi Nakanishi1 and Masako Izawa2

 

1The 21st COE Researcher, and  2Laboratory of Ecology and Systematics, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

The Iriomote cat Prionailurus bengalensis iriomotensis, a wild cat endemic to Iriomotejima Island, is the only indigenous medium-sized carnivore in the Ryukyu Archipelago. Recent molecular studies indicated that this cat is closely related to the leopard cat distributed from India and Southeast Asia to Russia and that the former was derived from the latter through migration to Iriomotejima island and subsequent isolation for about 200,000 years. Carnivores, occupying the top of the food chain, usually need wide ranges of habitats that guarantee constant provision of prey animals. The Iriomotejima Island (284 km2) is apparently too small for such medium-sized carnivores as the Iriomote cat. Moreover, except for some chiropteran species, no small indigenous terrestrial mammals that are almost always the staple of feline diet occur on this island. The survival of the Iriomote cat on Iriomotejima Island has therefore been regarded as a kind of enigma by mammalogists and ecologists.

We have studied food habits, home ranges, and activities of the Iriomote cat to solve this enigma. The scat analyses showed that the diet of this cat consists of an extraordinarily wide range of animal taxa, including not only such small mammals as the native fruit bats and the introduced black rats, but also various other native animals, such as the rails and thrushes (birds), colubroid snakes and scincid and agamid lizards (reptiles), ranid frogs (amphibians), and even crickets and freshwater shrimps (arthropods). It is interesting to note that the cat actually eats various non-mammalian animals: frequent predation on frogs by the Iriomote cat is particularly noteworthy, because this group of animals is very rarely preyed by other wild cat populations including those belonging to other leopard cat subspecies. Therefore, we can state that the dietary habit of the Iriomote cat is characterized by utilization of various animals available in its habitat largely irrespective of their taxonomic allocations.

The interesting food habit of the Iriomote cat was also indicated by the patterns of its activity and habitat use as revealed by our radio-tracking survey. The results indicated that each individual cat intensively uses the coastal lowland, apparently largely depending on streams and swamps there. Distribution of the scats also indicated that the individual density of the cat is much higher in the coastal lowland than in the inland mountainous area. The coastal lowland, encompassing various types of habitats, such as mangrove forests, swamps, and broad-leafed forests, may offer diverse prey to the cat throughout the year. The catŐs ability to utilize diverse animals from various habitats, including water-depending animals from riverin systems, seems to be the primary reason why it has survived on such a small, rodent-less island as Iriomotejima.

The home range size of the Iriomote cat, varying from 3—6 km2 in male and 2—5 km2 in female, was smaller than those of other leopard cats in Southeast Asia. Higher food availability and absence of other carnivores that would act as competitors on Iriomotejima Island seem to be the main causes for such difference. In addition, our survey by radio-tracking and other methods indicated that an individual Iriomote cat can alter the home range size and the prey animal species, probably in response to seasonal and annual changes of habitat condition and food availability. Long survival of the cat population on Iriomotejima Island also seems to be partially attributable to such ecological flexibility of this subspecies.

Since its initial establishment in about 200,000 years ago (see above), the population size of the wild cat on Iriomotejima Island seems to have thoroughly been a few hundred at most. Moreover, the current genetic diversity of the Iriomote cat is remarkably low, most likely reflecting extensive bottlenecks in the recent past. Nevertheless, the cat has been surviving to the present, obviously by taking advantage of the bountiful and relatively stable environment of this island.

It has recently been well documented that insular biota is often highly vulnerable to anthropogenic environmental changes, including a large scale of land development, and introductions of exotic organisms and diseases. Future survival of the Iriomote cat as an indicator of diverse, rich fauna of Iriomotejima Island obviously depends on how we can effectively keep on excluding these and other unfavorable factors from this island.

 

 

Oral -13

 

Current chelonian diversity in the East Asian Islands

 

Ryo Fujii

 

Department of Marine and Environmental Sciences, Graduate School of Engineering and Science, University of Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

The East Asian Islands, consisting of Japan and Taiwan, extends from subtropical zone in the southwest to subarctic zone in the northeast and represents two biogeographical realms, namely the Oriental region and the Palearctic region. Such a situation, along with the presence of several long standing straits crossing this island chain, makes taxonomic diversity of terrestrial animals in this region so high. Seven species of freshwater turtles are distributed in the East Asian Islands. In Japan mainland, two geoemydid turtles, Chinemys reevesii and Mauremys japonica, and one trionychid turtle, Pelodiscus sinensis, occur. From the Ryukyu Archipelago, three geoemydid turtles, Cuora flavomarginata, Geoemyda japonica and M. mutica, have been known. In Taiwan, four geoemydid turtles, C. reevesii, C. flavomarginata, M. mutica and Ocadia sinensis, and one trionychid turtle, P. sinensis, occur. All these Taiwanese species also occur in the eastern and southeastern parts of the Eurasian continent. Of these, C. reevesii exhibit prominent variation within a population in qualitative characters, whereas it shows little between-population variation. In quantitative characters, there were also no significant differences between any combinations of populations, although the Japanese population tended to be larger than the Taiwanese and the continental Chinese populations. In M. mutica, analyses of morphometric characters and coloration revealed that the Ryukyu populations are much diverged from the other populations, deserving recognition as a distinct subspecies, M. m. kami. However, my genetic analysis have yielded contradicting results, placing the Taiwanese populations much closer to the Ryukyu populations than to the continental populations. Geoemyda japonica is endemic to the central Ryukyus, with its closest relative, G. spengleri, being confined to the distant southeastern continental China and northern Indochina. These two species had long been considered as conspecific subspecies, but a recent comparative study demonstrated remarkable differences between these species in a number of qualitative characters. With respect to C. flavomarginata, morphometric analyses suggested the Ryukyu populations to be most divergent among conspecific populations, deserving taxonomic recognition at the subspecific level (C. f. evelynae). Recent studies proved that P. sinensis shows considerable genetic variation among the Japanese, Taiwanese and continental Chinese populations. Geographic variation has not yet been studied at all for M. japonica or O. sinensis. Characteristics of the turtle fauna of the East Asian Islands may be summerized as follows: 1) endemic species are recognized in Japan mainland and the central Ryukyus; 2) all taxa occurring in Taiwan also occurs in the continental China; 3) certain extent of variations exist between conspecific populations of Taiwan and the southern Ryukyus; and 4) in widespread species, Taiwanese populations may be closer to the continental population than the Japanese population (but see the case of M. mutoca mentioned above). The geographic faunal pattern of the East Asian turtles is in good agreement with the currently prevailing scenario for the history of dispersals and vicariances of several other terrestrial organisms in this region.

 

 

Oral -14

 

Biogeography and evolutionary patterns of landsnails on the island of Borneo

 

Thor-Seng Liew

 

Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Loacked Bag 2073, 88999 Kota Kinabalu, Sabah, Malaysia

 

The northern part of Borneo (Sabah) has experienced the islandŐs most active and recent tectonic processes, which include the expansion of land area (from the Middle Eocene to the Middle Pliocene) and climate fluctuations (during the Pleistocene). The interplay between geology and climate generates extraordinary diversity and genetic distinctiveness among species. However, the effects of historical processes on contemporary distributions of landsnails in Borneo are not known. The mitochondrial DNA sequences from 16S rRNA and COI genes, and nuclear ribosomal DNA sequences from ITS-1 were used to investigate phylogeographic patterns among two landsnail genera: Everettia (Gastropoda: Ariophatidae) and Meghimatium (Gastropoda: Philomycidae) in Northern Borneo. Maximum parsimony and maximum likelihood analyses on these genetic datasets produced trees in general agreement with phylogeographical patterns in both genera. Their taxonomy (based on the morphology) was also well-supported by genetic data. The resulting diversity and phylogeography for both groups of landsnails can be linked to major vicariance events in the Miocene and Pliocene. The phylogenetic trees also showed that a number of endemic species on Mount Kinabalu are possible remnants from the Pleistocene climate fluctuations.


 

Oral -15

 

Fossils of terrestrial turtles indicate the Late Pleistocene mass extinction

in the East Asian Islands

 

Akio Takahashi

 

Faculty of Science, University of the Ryukyu, Nishihara, Okinawa 903-0213, Japan

 

Extant terrestrial turtle fauna of the East Asian Islands consists of seven species (six geoemydids and one trionychid). Of these, Geoemyda japonica and Mauremys japonica are endemic to the Okinawa Group of the Ryukyu Archipelago and Japan mainland, respectively, whereas Cuora flavomarginata and M. mutica are distributed in the Yaeyama Group of the southern Ryukyus, Taiwan, and the eastern part of the continent. The southern Ryukyu populations of the latter two species are distinguished from their conspecific Taiwanese and continental populations as endemic subspecies (C. f. evelynae and M. m. kami). Chinemys reevesii and Pelodiscus sinensis occur in Japan mainland, Taiwan, and the continent. The remaining species, Ocadia sinensis, ranges from southeastern continent to Taiwan. Based on the zoogeographic and physical information, it is very likely that Taiwan was connected to the continent in the Last Glacial Maximum in the Late Pleistocene, whereas the other islands remained isolated from the continent, as well as from each other during this period. Terrestrial turtles do not seem to be tolerant to seawater for oversea dispersals, because their natural ranges do not include oceanic islands at all. Thus, it is obvious that the ancestors of the current terrestrial turtles of the East Asian Islands had colonized from the continent to these islands through landbridges.

Recently, taxonomic studies on terrestrial turtle fossils from the Quaternary of the East Asian Islands have been rapidly progressing, showing that the turtle fauna in this region was much more diverse in the Pleistocene than in the present. For example, from the Upper Pleistocene of the central Ryukyus (i.e., the Amami and Okinawa Groups, and a few southern islands of the Tokara Group), two extinct geoemydids (i.e., Cuora sp., obviously different from C. flavomarginata; G. amamiensis, endemic to the Amami Group and closest to G. japonica) have recently been found. Besides these, one more geoemydid species, for which generic status has not yet been determined with certainty, but obviously different from extant turtles of the archipelago, was also found from one island (Kumejima) of the central Ryukyus. From the southern Ryukyus, one extinct geoemydid, Mauremys sp. has been discovered from comparable deposits on Miyakojima Island. Moreover, an endemic testudinid (Manouria oyamai) was recently described from both the southern and central Ryukyus. In Japan mainland, three extinct endemic geoemydids, C. miyatai, M. yabei, and O. nipponica, have been recorded from the Middle to Late Pleistocene deposits. These Pleistocene turtles of Japan mainland and the Ryukyus had probably been differentiated through insular isolation mainly caused by sea level changes during the Pleistocene. Majority of such terrestrial turtles of the East Asian Islands had gone extinct in the latest Pleistocene, leaving only a few species surviving to the present. The abrupt extinction of those turtles is most likely a part of the mass extinction of terrestrial vertebrates during this period, which seems to have been caused by prominent climate change, or human activities, or both.

 

 

Oral -16

 

The Late Pleistocene snake fauna (Reptilia: Squamata) of the Ryukyu Archipelago, Japan, as inferred from recently discovered fossils

 

Tadahiro Ikeda

 

Tropical Biosphere Research Center, University of the Ryukyus, Nishihara,

Okinawa 903-0213, Japan

 

The Ryukyu Archipelago is a chain of continental islands located in the subtropical East Asia between Japan mainland and Taiwan. This archipelago is usually divided into three regions, the northern Ryukyus, the central Ryukyus, and the southern Ryukyus, by the Tokara Tectonic Strait in northeast and the Kerama Gap in southwest. These regions show sets of extant terrestrial animals distinct from each other. Formation process of such distinct geographic pattern in the current Ryukyu fauna yields a number of questions to be answered. Fossil studies often offer good clues to such questions. Indeed, a number of fossil vertebrae of snakes has been collected from the Upper Pleistocene cave and fissure filling deposits on several islands of the Ryukyus (Tokunoshima, Okinawajima, Miyakojima, Ishigakijima, and Yonagunijima Islands), and these may possibly contribute to the solution of some of these questions. However, due to the difficulties in their reliable identifications, many of these fossil snake vertebrae have been left unidentified, or were identified but without any concrete justifications, offering little biogeographical information. Keeping this problem in mind, I have been working to establish a reliable identification system of snake vertebrae on the basis of extant snake specimens from East and Southeast Asia. I have also attempted to apply this system to the identification of fossil snake vertebrae excavated from the Ryukyu Archipelago.

As a result, fossil snake vertebrae excavated from each island of the Ryukyus were identified to four genera of three families, such as the genus Dinodon of the family Colubridae and the genus Protobothrops of the family Viperidae. These fossils suggest that Late Pleistocene snake fauna on each of Tokunoshima, Okinawajima, Ishigakijima, and Yonagunijima Islands is very similar to that at present, and these fossil snakes are therefore considered as the ancestor forms of the extant snakes on each island. In contrast, the Late Pleistocene snake fauna of Miyakojima Island was considerably different from the extant snake fauna of the same island: some fossil vertebrae of the Colubridae, for example, clearly differ in size and several other morphological characters as compared with extant colubrids of Miyakojima and other islands of the Ryukyu Archipelago. Moreover, fossil vertebrae of the viperid taxa, such as Protobothrops cf. P. elegans, were also excavated from Miyakojima Island, but not a single viperid species currently occurs on this island. These and other fossil evidences clearly indicate that on Miyakojima Island a number of snake taxa has gone extinct since the Late Pleistocene.

The vertebrae found from those Ryukyu islands as the Pleistocene fossils were distinctly larger in size than those of their extant putative descendants of the same islands (see above). Such prominent size differences between fossil and extant snake vertebrae suggest that in each lineage of snakes, the body size has rapidly reduced during the last few hundred thousand years, probably due to the reduction in size and density of available prey, such as the frogs and birds.

 

 

Oral -17

 

Cynocephalus variegatus (Dermoptera) and Manis javanica (Pholidota): examples of neglected mammalian orders

 

Norman Lim

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Even though most biologists feel that mammals is the most well-studied group of animals, there is still a great gap in our knowledge on the basic ecology of many tropical nocturnal species. For instance, what we know of the biology of the 37 species of cats is far from being complete. The Cynocephalus variegatus and Manis javanica are two examples of such animals, which belong to very unique mammalian orders and still exist on the largely urbanized island of Singapore. I will present on the natural history of these two very different animals and also discuss the characters that render them and others species being neglected in mammalogy


Oral -18

 

The Late Pleistocene-Holocene changes in the distribution and body size of amphibians on Okinawajima Island, the Ryukyu Archipelago, Japan

 

Yasuyuki Nakamura

 

Graduate School of Engineering and Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa 903-0213, Japan

 

The fossil study is one of the most effective ways to uncover the past temporal changes of organismal diversity at a given locality and in a given evolutionary lineage. For the Quaternary insular fauna, this approach is known to be particularly fruitful in that it sometimes clarifies various historical biological phenomena in a given clade, such as the evolutionary changes in body size and other morphological characters, and diversification and extinction caused by environmental changes. To take advantage of such paleontological approaches, however, there are at least two strict preconditions as follows: (1) soil of the area in problem should be favorable to fossilization of dead bodies of organisms; and (2) organisms in problem should have hard body parts, such as bony elements, which can be easily fossilized. The southern part of Okinawajima Island, the Ryukyu Archipelago, is one of the major sources of the Quaternary terrestrial animal fossils in Japan, because this area is broadly covered by the Pleistocene limestone, and, therefore, infills of fissures developed in the limestone cliffs and floor deposits of the limestone caves, both usually dated back to the Late Pleistocene, contain numerous fossil remains. However, very few studies have yet been conducted on the fossils from this region, and this situation is particularly true with amphibians despite high abundance of their fossils at some fissures and caves. I have examined morphological features of amphibian fossils collected from two chronologically different fissures in the southern part of the island. Detailed comparisons using skeletal specimens of various extant species revealed that these southern Okinawajima fossils represent no less than eight species that also occur on Okinawajima at present. Of these species, five, Rana holsti, R. ishikawae, R narina, R. sp., and Limnonectes namiyei, do not currently occur in the southern part of the island, where vegetation is relatively open and the surface waters are limited and mostly temporary at present: these five species are currently confined to the northern part on this island, where the deep subtropical broad-leaf forest predominates with a number of constantly running streams on the floor. Because all these five species require the year-round existence of running waters for reproduction and completion of larval growth, discovery of their fossils from the southern part strongly suggests that the Late Pleistocene natural environment of this region was distinctly different from that in the same region, but similar to that in the northern part at present. These frogs seem to have disappeared from the southern part during the last 20,000 years, as a result of deterioration of the natural vegetation, which was caused by the climatic change and, presumably, also by the anthropogenic environmental changes. Moreover, our studies have revealed that in several frog species body size is statistically significantly larger in the fossil individuals than in the extant animals. The body size in some species also differed between the two different fossil sites (see above).  Possible factors responsible for such body size variations are discussed.

 

 

O-19

 

The unique biodiversity of Pulau Tioman, Malaysia

 

Tan Heok Hui

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

 

Pulau Tioman is the largest island off the East coast of Peninsular Malaysia and is home to many interesting botanical and zoological organisms. Of interest here, the endemic freshwater brachyurans, ichthyological and herpetological examples are highlighted. Recent papers and unpublished results are also incorporated as further evidence of TiomanŐs uniqueness.


O -20

 

Plant distribution patterns in the Ryukyu Archipelago, Japan

in the light of seed dispersal abilities

 

Koh Nakamura1, Tetsuo Denda2, and Masatsugu Yokota2

 

1The 21st Century COE Program, and  2Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

The Ryukyu Archipelago is an assemblage of continental islands that lie between Taiwan and mainland Japan for approximately 1300 km. The climate is subtropical and moderate throughout the year and the islands are covered by well developed broad-leaved evergreen forests. On the basis of its submarine topography, the Ryukyu Archipelago is subdivided into three areas (the northern, central, and southern Ryukyus) at the Tokara tectonic strait (the Tokara Gap) and the Kerama Gap, where the sea bottom is more than 1000 m deep. These two gaps are the oldest channels in the Ryukyu Archipelago, which first segmented the land bridge connecting the Asian continent, via Taiwan and the Ryukyu Archipelago, with mainland Japan in the Pliocene or early Pleistocene. In consideration of this geographical characteristics, preceding floristic geographic studies in the Ryukyu Archipelago placed demarcation lines between the northern and central Ryukyus, and/or between the central and southern Ryukyus, based on distribution records of a few particular elements of the flora, such as endemics, mangrove plants and sea grasses (e.g., Hara, 1959; Good, 1974; Maekawa, 1974; Takhtajan, 1986; Kitamura et al., 1994). Also, we conducted more quantitative analysis on the floristic demarcations, collecting distribution records of all the seed plants (approximately 1800 species) on major islands from several literature sources into a data matrix, and revealed that the flora of the Ryukyu Archipelago is hierarchically structured as (northern Ryukyus, (central Ryukyus, southern Ryukyus)).

This time, we use subsets of the floristic data in the light of different seed dispersal abilities and further investigate the influence of these deep oceanic channel divisions on the floristic differentiation in this archipelago, taking account of the influence of isolation by mere geographic distances among islands. We examined local patterns of the correlation between pairwise floristic dissimilarity and geographic distance among the islands; if floristic dissimilarity distance is not correlated with geographic distance locally, barriers (not isolation by geographic distance) are likely causing the differentiation of floras. Analysis on the influence of the deep oceanic channel divisions on the floristic differentiation is expected to advance our understanding of floristic plant geography in such island chains.

 

 

Oral -21

 

Population genetics of the Joey palms, Johannesteijsmannia H.E.Moore (Palmae)

 

Look Su Lee

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Johannesteijsmannia is a palm genus of four tropical rain forest understorey species. Only Jt. altifrons is widespread, ranging from southern Thailand, Peninsular Malaysia, Sumatra to western Borneo while Jt. lanceolata, Jt. magnifica and Jt. perakensis are endemic to Peninsular Malaysia. Their increasing commercial exploitation as ornamental plants makes conservation a priority. To conserve effectively, more understanding is needed about their genetics variation within and between populations of each species.

AFLP fingerprinting was generated using six primer combinations on DNA samples from 222 individuals collected from 27 populations throughout the distribution of Johannesteijsmannia. Jt. altifrons exhibited the highest genetic diversity of all. Populations of each species exhibited moderate genetic diversity (NeiŐs genetic diversity values ranged from 0.0861–0.1968 and the Shannon information index, from 0.0677–0.2355). Results of the Analysis of Molecular Variance (AMOVA) showed that all congeners partition higher genetic diversity within population (63%–88%) than between populations (12%–37%). The population differentiation measure, the Fst value, was highly significant (P < 0.001) and ranged from 0.1235 (Jt. magnifica) to 0.3277 (Jt. altifrons) indicating that there is gene flow between populations of each species. AMOVA results were corroborated by Bayesian analysis with significant Fst values for all species. The best model selected was f = 0 (f being the inbreeding coefficient), suggesting all congeners are outcrossing species. Results from Mantel test demonstrated there is a significant correlation between geographical and genetic distance in Jt. altifrons but insignificant for the others.

 

 

Oral -22

 

Cytological diversity of the genus Hydrangea (Saxifragaceae)

in the Ryukyu Archipelago of Japan

- On the origin of tetraploid Hydrangea liukiuensis endemic to Okinawajima Island –

 

Tetsuo Denda

 

Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

Despite corresponding to roughly 1 % of the area of Japan, the Ryukyu Archipelago support more than 1600 seed plant species. This marvelous plant diversity in the current Ryukyu Archipelago must have been established due to the influence of the paleogeographical dynamics of this area. In addition, such speciation processes as interspecific hybridization and polyploidization appear to play an important role in creating plant diversity in the Ryukyus. Some examples of the intraspecific polyploidy have been reported from the Hydrangea chinensis-complex that comprises five species distributed in the Ryukyu - Taiwan region. Of the five species, H. chinensis, H. grosseserrata and H. kawagoeana are diploid (2n=36), while H. liukiuensis has diploid (2n=36) and tetraploid (2n=72) cytotypes, and H. yayeyamensis has octoploid (2n=144) and decaploid (2n=180) cytotypes. In this workshop, I will focus on the origin of tetraploid H. liukiuensis inferred from chloroplast and nuclear DNA sequences.

Hydrangea liukiuensis is a small shrub endemic to Okinawa-jima Island of the central Ryukyus. In a preliminary cytogeographical survey of this species, only diploids were found in 15 of 18 populations investigated, whereas tetraploids occurred at remaining three populations (Mt. Nekumachiji, Taiho Riv., Mt. Yae). Intra-population variation in the ploidy level was observed in Taiho Riv., in which diploids were dominant and only four tetraploids grew next to each other. Ten diploids and six tetraploids of H. liukiuensis, together with H. chinensis (Taiwan), H. grosseserrata (Yaku-shima Isl.) and H. yayeyamensis (Ishigaki-jima and Iriomote-jima Isls.) were used for molecular analysis. Cardiandra alternifolia (Hyogo Pref.) was also used as an out-group. The trnS/trnG intergenic spacer region (trn S-G region) of the chloroplast DNA and the internal transcribed spacer region (ITS) of nuclear ribosomal DNA were PCR amplified and sequenced. Most parsimonious (MP) and maximum likelihood (ML) trees were then constructed based on the nucleotide sequence of each region. On the MP and ML trees of trn S-G region, H. liukiuensis was monophyletic with high bootstrap values (97% and 95%, respectively) and this clade was sister to one composed of remaining three Hydrangea species. On the other hand, tetraploids of H. liukiuensis were nested with H. chinensis, H. grosseserrata and H. yayeyamensis to construct a monophyletic clade on the MP and ML trees of ITS region (bootstrap values of 60% and 55%, respectively). This clade was sister to a monophyletic clade composed of all diploids of H. liukiuensis. This incongruence between chloroplast and nuclear DNA phylogenies of H. liukiuensis seem to suggest an allopolyploid origin of tetraploid H. liukiuensis. However, no other Hydrangea species except H. liukiuensis are distributed on Okinawa-jima Island. Past interspecific hybridization event(s) between diploid H. liukiuensis and an extinct parent may have caused the origin of tetraploid H. liukiuensis.

 


Oral -23

 

CTFS and the Bukit Timah Project

 

Shawn Lum

 

National Sciences and Science Education Academic Group, National Institute of Education, 1 Nanyang Walk, Singapore 637616

 

 

Oral -24

 

Biodiversity and conservation of non-vascular plants in Asia

- what lessons can we learn from mosses?

 

Benito Tan

 

The Herbarium, Singapore Botanic Gardens, Nparks, Singapore

 

A review of the moss biodiversity in selected countries in Asia at different latitudes is presented with consideration of the area size of the country. It appears that the moss biodiversity at high latitudes is as diverse in term of number of species as in the tropics near the equator. Recent studies also show tht mosses, as a group of land plants, can survive longer in their microhabitats, after the original forest vegetation is seriusly disturbed. Having still undiscovered economic values, it is proposed that the moss diversity in Asia be best preserved together with other groups of plants and animals in protected nature reserves.

 

 

Poster -1

 

A systematic study of crustose coralline algae (Corallinales, Rhodophyta)

 in the Ryukyu Islands

 

Aki Kato1, Masasuke Baba2, and Shoichiro Suda3

 

1Graduate School of Engineering and Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan, 2Marine Ecology Research Institute, Kashiwazaki, Niigata 945-0017, Japan, and 3Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan

 

Crustose coralline algae (Corallinales, Rhodophyta) are widely distributed from the polar to tropical regions all over the world. Crustose coralline algae (CCA) are completely calcified and play very important roles as reef-building organisms. CCA are biogeographically and paleoecologically unique, because the present distribution pattern of CCA are less likely to reflect recent dispersal by human activity, and because fossil records are available for paleoenviromental studies.

In the Ryukyu Islands, approximately 20 crustose coralline species have been reported in eight genera of three families, more than half of which are also known in the tropical Indo-Pacific region. However, some of these species have unclear species definitions. Moreover, there have been few molecular studies of CCA at the species level, and no study using molecular data of CCA from Japan have been conducted so far. The reason for this lack of molecular studies on CCA is that species identification requires observation of anatomical structures of vegetative and reproductive organs of calcified specimens, which takes a longer time than for non-calcified and non-crustose algae.

The present study is being undertaken to determine DNA sequences of small subunit ribosomal RNA (18S rDNA) of six CCA species commonly found in the Ryukyu Islands to confirm that these species are the same as species that are distributed in the other regions, with the aim of ultimately providing clues to taxonomically revising CCA species and elucidating the biogeographic relationships of CCA in the Indo-Pacific region.

In our preliminary results, five CCA species exhibited high genetic variation compared to one other species, Pneophyllum conicum. 18S rDNA sequence divergences of P. conicum from Japan (n=1) and Hawaii (n=5) ranged 0.1-0.6%. In contract to P. conicum, sequence divergences of Lithophyllum kotschyanum from Japan (n=1), Hawaii (n=2) and Fiji (n=1) were 0.6-2.0%; Hydrolithon onkodes from Japan (n=1) and Australia (n=1), 3.7 %; H. reinboldii from Japan (n=1) and Hawaii (n=4), 0.1-3.2%; Neogoniolithon brassica-florida from Japan (n=1), Australia (n=1) and Hawaii (n=2), 0.1-3.7%; and Mesophyllum erubescens from Japan (n=1) and Hawaii (n=2), 1.1%.

What causes such different levels of genetic variation? First, the true species diversity is likely to be underestimated because of the limited number of the morphological characters. In recent taxonomic studies of CCA, species circumscriptions focus on reproductive structures rather than gross morphology and vegetative structures. For example, N. brassica-florida was synonymized with several previously described species that are now considered to be growth forms of N. brassica-florida. However, this species may include some genetically and morphologically different species. Secondly, the lower levels of genetic variation in P. conicum may be caused by a reduced mutation rate, although it seems unlikely that such a large difference in mutation rate exists between algae occupying similar ecological niches within the same order. Thirdly, P. conicum from Japan and Hawaii is apparently genetically conspecific. To confirm whether species examined consist of either several cryptic species or even different species, further morphological and molecular studies of several specimens of each species need to be conducted.

 

 

Poster -2

 

Species diversity and potential growth rates of common scorpaenids found in coastal Singapore shores

Jeff T. B. Kwik1, T. M. Sin2 and Peter K. L. Ng1

1Department of Biological Science, National University of Singapore, 14 Science Drive 4, Singapore 117543, and
2Tropical Marine Science Institute, National University of Singapore, 14 Kent Ridge Rd, Singapore 119223

 

The ecology of scorpaenids is poorly studied. Present information stems primarily from venom studies and a few taxonomic descriptions which have dealt with the toxicity and biochemistry of stonustoxin. In general, little much has been done with regards to studying the general biology and ecology of stonefish and other scorpaenids. In determining the growth rates of common scorpaenids found in Singapore, a two month sampling census at 24 sites around coastal Singapore indicated that there are eight species of scorpionfish found locally thus far. The most common species included long spine scorpionfish, Paracentropogon longispinnus, the stargazer waspfish, Trachycephalus uranoscopus and estuarine stonefish, Synanceja horrida respectively. The largest scorpaeind found in Singapore was S. horrida while the smallest was P. longispinnus. Otoliths extracted from these three common species indicate that the relative growth rates could potentially be determined using otolith weight in relation to body size for P. longispinnus, T. uranoscopus and S. horrida. However, validation of age using electron microscopy of otoliths for these species will be required to confirm this finding.

 

 

Poster -3

 

The union of Barcoding and Taxonomy: A case study in the commercially valuable blue swimming crab, Portunus pelagicus species complex
 
Joelle C.Y. Lai1 and Peter F. Davie2

 

1Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore, and 2Queensland Museum, Brisbane, Australia

 
Whilst DNA barcoding has been shown to uncover hidden pockets of biodiversity in different animal groups, species discovery via barcoding should nevertheless be carried out in tandem with careful morphological analysis, knowledge of biogeographic information and judicious checking of historical literature to maximise its full value to the scientific community as well as in practical situations. In our case, analyses of COI sequences and morphology of the marine swimming crab Portunus pelagicus showed that it is in fact a complex of at least four species. However, while unique Molecular Operational Taxonomic Units (MOTUs) may be morphologically indistinguishable, we also have what would be considered as a single MOTU comprise of two species with pronounced morphological differences between them. Using a complement of various methods, we have clarified the systematics of this commercially important group of species group. In the process, we have maintained nomenclatural stability as far as possible yet assign pre-existing names to each “rediscovered” species.

 

 

Poster -4

 

A new cavernicolous freshwater crabs from Samar, Island, Philippines

 

Daniel Edison M. Husana1*, Tomoki Kase1** and Tohru Naruse2

 

1National Science Museum, Tokyo, *Department of Natural Environmental Studies, Graduate School of Frontier Science, The University of Tokyo, Japan, **Department of Evolutionary Biology, Graduate School of Science, The University of Tokyo, Japan, and 2Department of Biological Sciences, National University of Singapore

 

A new cavernicolous freshwater crab of the genus Sundathelphusa is described from Langun-Gobingob cave in Samar, Island, Philippines. The new species has greatly reduced eyes, absence of body pigmentation and noticeably elongated ambulatory legs typical to cave obligate crabs. The new species is clearly distinct from all known cavernicolous Sundathelphusa by its spiny pereiopods. The cave is located in one of the archipelagoŐs largest karst formation (about 2970 hectares) situated in the Western Samar province. Specimens of the new species were collected from two separate locations of the cave system. One is in the very big chamber of the cave, about the size a football field stadium, approximately 100 meters from the opening. Here, the new species was collected from the water trapped in mud holes caused by footsteps along the bank of small subterranean stream. Others were collected from the shallow pools of subterranean river located in another chamber approximately 150 meters from the outside which could only be accessed through a small hole. The two chambers were separated by a huge limestone wall and are both in complete darkness.

 

 

Poster -5

 

Updating records of zooxanthellate scleractinian corals in Singapore

 

D. Huang, K. P. P. Tun, and L. M. Chou

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Singapore's hard coral species records have not been updated in the last 12 years. We present an inventory of zooxanthellate scleractinian species through field surveys at eight reef sites, and consolidation of past work, RMBR reference collection and recent publications. Species assessment surveys and recent literature revealed a total of 165 species, 30 of which are new records, increasing the number of species ever found in Singapore from 189 to 258. Raffles Lighthouse registered the largest number of species and represents the most undisturbed reefs of the sites studied. Taking into account reef area, the number of species in Singapore is comparable to reefs in neighbouring countries. Only 64.0% of total species recorded have been found in recent years, but this study is not exhaustive in terms of sampling effort and site coverage. As 11.6% of all species have been newly recorded in the last three years, and only 52.0% of species with distribution ranges encompassing Singapore have been found, a larger inventory can be expected with more rigorous assessments.

 

 

Poster -6

 

History of taxonomic recognition of reptile diversity in the East Asian Islands

 

Hidetoshi Ota

 

Tropical Bioshere Research Center, University of the Ryukyus, Nishihara,

Okinawa 903-0213, Japan

 

The East Asian Islands consists of several hundred of inhabited islands and uninhabited islets of Japan and Taiwan, and is located in the eastern off-shore of the Eurasian continent. It extends from the cool-temperate zone in northeast to the subtropical zone in southwest. Such topography, along with its diverse geomorphology, makes the climate of this region highly variable, offering diverse temperature, humidity and precipitation environments to its terrestrial organisms. Geologically the East Asian Islands is characterized by radical and complicated tectonic movements, which often lead to heavy earthquakes and cause remarkable uplifting and subsidence of localized crusts. To the terrestrial animals with limited ability of oversea dispersals, formation of a landbridge and its subsequent fragmentaion, involved by such tectonic movements and also by the eustatic sea level changes, offer good opportunities of range extension and vicariance. Indeed, terrestrial fauna of the East Asian Islands is characterized by a high degree of endemism and distinct difference in species composition even between neighboring areas, when they are separated by long standing straits.

The taxonomic description of terrestrial animals in the East Asian Islands was first started in the early 19th Century by a few European naturalists. Since then, nearly two centuries have passed. Nevertheless, a huge number of new and newly recorded taxa are still reported from this region every year. On this opportunity, I review the history of taxonomic recognition of reptile diversity in this region.

Over 160 native species and subspecies of terrestrial reptiles have been reported from the East Asian Islands. From Japan, 80 are currently recognized, of which nearly 3/4 are endemic to this region. With respect to Taiwan, more than 80 species and subspecies are also reported, of which, however, less than half are endemic. The difference in the ratio of endemic taxa between the two regions seems to reflect the difference in their history as isolated islands: many of the Japanese islands are considered to have been consistently isolated from the continent for more than one million years, whereas the main island of Taiwan, where most Taiwanese species and subspecies occur, seems to have connected to the continent around 15,000—20,000 years ago, when the sea level lowered by ca. 120 m as a result of continental glaciation.

Of the native taxa of terrestrial reptiles in the East Asian Islands, more than 2/3 were described or recorded from this region by the middle of the 20th Century, and over 9/10 by the early 1980s. However, with the progress and prevalence among taxonomists of molecular and cytogenetic techniques that are quite effective in detecting morphologically poorly diverged but genetically distinct or reproductively isolated species, the number of taxa newly discovered from the East Asian Islands have started to increase again during the last two decades. The temporal pattern of increase of the reptile taxa recognized from this region predicts that a substantial portion of the cryptic taxonomic diversity still remains to be appropriately recognized.

 

 

Poster -7

 

Taxonomy, biogeography, and conservation of tarsiers

 

Myron Shekelle

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Hill (1955) classified tarsiers into three species, each from a distinct biogeographic region: Tarsius bancanus from island areas of Sundaland, T. syrichta from islands of the southern Philippines, and T. tarsier (=spectrum) from Sulawesi and nearby islands.  Multiple species and/or subspecies have been described from each region, and each of these three taxa may be a cluster of related taxa. The distribution of T. syrichta conforms well to the Ice Age landmass Greater Mindanao. The distribution of the T. tarsier-complex covers the Ice Age landmass of Sulawesi, and extends to discontiguous island groups, possibly indicating a relatively ancient dispersal throughout the proto-Sulawesi archipelago.  The distribution of T. bancanus is limited to a greatly reduced subset of Sundaland, and may indicate a Holocene range expansion from a Pleistocene refuge in Borneo. The alpha-level taxonomy of the T. tarsier-complex is reviewed.  Acoustic evidence provides a hypothesis of at least 17 distinct taxa, 16 known acoustic forms plus the enigmatic T. pumilus. The distribution of tarsier acoustic forms conforms to empirical biological and geological data to form a compelling biogeographic hypothesis for Sulawesi. Congruence among tarsier acoustic, genetic, and morphologic data is reviewed. One implication for conservation is that biodiversity in Sulawesi may be underestimated by as much as an order of magnitude. Rigorous testing of the hypothesis of so many new taxa will require a large investment of resources and time, but regrettably, current rates of deforestation indicate that time may be of short supply.

 

 

Poster -8

 

Cryptic species: What we donŐt know might hurt us

 

David Bickford

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

The taxonomic challenge posed by cryptic species has been recognized for nearly 300 years, but the advent of relatively inexpensive and rapid DNA sequencing has given biologists a powerful new tool for detecting and differentiating morphologically similar species. Here, we synthesize the literature on cryptic and sibling species and discuss trends in their discovery. However, a lack of systematic studies leaves open the tantalizing questions such as whether cryptic species are more common in particular habitats, latitudes or taxonomic groups. Such uncertainties could have profound implications for evolutionary theory, biogeography planning and conservation planning.

 

 

Poster -9

 

Text Box: Insular biogeography of web-building spiders on small tropical islands surrounding Singapore

 

Adrian L. Lim and Daiqin Li

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

The main objective of this study was to investigate biogeographical effects that influenced the distribution and assemblage of web-building spiders on small tropical islands off Singapore in order to understand how this group of arthropods responded to biogeographical, environmental and human factors. Fifteen islands were sampled for web-building spiders. Correlation analysis, simple linear and multiple regressions, nestedness index and choros (K) model were used to test the six specific predictions that (1) area is the best predictor of species/genus richness at both community and specific/generic levels; (2) there is no correlation between island size and population density; (3) web-building spiders are non-randomly distributed on the islands and exist as nested subsets; (4) there is a correlation between environmental variables and web-building spider species/genus distribution; (5) body size (chelicerae to end of abdomen) of female insular Nephila pilipes increases with increasing island area; and (6) the choros (K) (Triantis et al., 2003) model offers a better-fit than the classic species-area one.

      Area per se was found to be the most significant factor accounting for web-building spider assemblage at both community and specific/generic levels. Contrary to the theory of Island Biogeography, there was a positive correlation between island size and population density. Web-building spiders were also found to be non-randomly distributed on islands, suggesting that smaller islands were sustained in a subset of a more complete one found on larger islands. CCA results showed that spiders were associated with specific environmental variables. A majority of them apparently preferred sites with bigger trees with more canopy cover. Furthermore, the body size of N. pilipes females was significantly correlated to island area and distance from Malaysia, the assumed source island for web-building spiders. A larger island and sites found closer to Malaysia harboured greater species richness. Finally, the K model provided an improved goodness-of-fit to account for the spider data.

      We concluded that many factors could account for the distribution of web-building spiders on these small tropical islands but island area per se is the most important factor. Habitat diversity was not shown to play a major role until the usage of choros (K) which superceded island area as the best predictor of species distribution. Moreover, conservational strategies should accorded highest protection priority to the bigger islands, i.e. Pulau Ubin as it not only has the highest species richness but also contains many other species not recorded on other islands, and the responses of individual species must also be studied before embarking on a conservation project.   

 

 

Poster -10

 

Resolving species limits within Dicranosepsis

 

Hwang Wei Song

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Dicranosepsis is the most speciose genus of black scavenger fly (Sepsidae) in South-east Asia. Species limits are problematic for species with few morphologically diagnostic features and cases of cryptic species are suspected to exist within the species currently listed as ÔwidespreadŐ. Here the use of morphology, DNA and reproductive isolation tests is adopted to help resolve species limits and to test recently proposed methods in DNA taxonomy. The overall level of congruence between morphological and molecular data is low due to greatly differing rates of speciation in different Dicranosepsis species. The different rates are not well reflected in COI sequences. DNA taxonomy methods are thus not satisfactory in delimiting species. In contrast, consistent results between morphology and reproductive isolation support the relevance of foreleg morphology for species delimitation within Dicranosepsis. Cases of peripatric speciation and rapid speciation are discussed and widespread species are documented that have few morphological modifications but large COI divergences. Cryptic species are not described here because of a lack of reproductive isolation evidence.

 

 

Poster -11

 

Biogeographical patterns of molluscs on tropical limestone karst ÔislandsŐ

 

Reuben Clements

 

Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Limestone karst outcrops are de facto terrestrial islands because they are isolated from one other by non-calcareous substrates. This spatial structure restricts gene flow between isolated karsts, with the result that certain taxonomic groups exhibit high endemicity via allopatric and/or parapatric modes of speciation. For terrestrial molluscs, tropical karsts are generally considered evolutionary hotspots for speciation. However, there is a paucity of biogeographical studies on karst malacofaunas in general. Using molluscan species data we: (1) identified correlates of endemism from a set of important biogeographical factors (i.e., karst area, isolation, surrounding soil type and geological age); and (2) investigated how species compositions varied among different karsts in two biogeographical regions (Peninsular Malaysia and Sabah, Malaysian Borneo). Generalized linear mixed-effect models (GLMM) were used to determine correlates of endemism, while non-metric multi-dimensional scaling (NMDS) was used to investigate species compositional variations. Sampling yielded a total of 198 terrestrial mollusc species. GLMMs revealed an important contribution of karst area and surrounding soil type on mollusc endemic richness, while NMDS showed that karsts separated by vicariant barriers in different parts of Peninsular Malaysia and Sabah had distinct malacofaunas. These results have important conservation implications: planners should take karst area and surrounding soil type into account, together with the effects of vicariant barriers such as mountains, when designing karst reserves in order to maximize the protection of invertebrate diversity.

 

 

Poster -12

 

First inventory of the aquatic and semi-aquatic bugs (Heteroptera: Nepomorpha & Gerromorpha) of Langkawi Island, West Malaysia

 

H. Zettel1 and A.D. Tran2

 

1International Research Institute of Entomology, Natural History Museum Vienna, Austria, and 2Department of Biological Science, National University of Singapore, 14, Science Drive 4, Singapore 117543, Republic of Singapore

 

Langkawi Island (Pulau Langkawi) is situated off the northwest coast of Peninsular Malaysia, in the southern Andaman Sea. Although the water bug fauna of the Malay Peninsula is relatively well known, knowledge on the fauna of Langkawi is almost none, except for three reliable species records from Langkawi in the literature: Halobates hayanus White, 1883, Haloveloides sundaensis Andersen, 1992 and Xenobates murphyi Andersen, 2000. In 2006, we and Dr Tohru Naruse visited Langkawi for three days to explore the diversity of water bugs. The intensive collections primarily focused on habitat diversity (freshwater habitats, mangroves, and rocky shores) to record as many species as possible. Additional specimens collected from the island by Dr Damir Kovac in 1993 (deposited in Raffles Museum of Biodiversity Research, Singapore) are also included in this study. This survey unveils 52 species (47 species identified) belonging to 31 genera and 11 families from the island. Most of the species belong to two families, the Gerridae (19 species) and the Veliidae (12 species), while the remaining nine families together contain only 21 species. This agrees proportionally with the species numbers known from the Malay Peninsula. Three species are new to science, they are of the genera Hydrotrephes (Helotrephidae), Strongylovelia and Microvelia (both Veliidae). Another nine species are recorded from Malaysia for the first time. The fauna of Langkawi Island is compared with those of Tioman Island, where intensive surveys were carried out in the past, and of the Malay Peninsula.

 

 

Poster -13

 

Comparative studies on woody species diversity and structure in subtropical evergreen broadleaf forests along a latitudinal thermal gradient of the Ryukyu Archipelago

 

S. M. Feroz, Akio Hagihara, and Masatsugu Yokota

 

 Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan

 

In order to compare woody species diversity and stand structure on the basis of the architectural stratification of subtropical evergreen broadleaf forests along a latitudinal thermal gradient of the Ryukyu Archipelago, tree censuses in a 750 m2 plot in Okinawa Island and a 400 m2 plot in Ishigaki Island were performed. The number of layers increased along a latitudinal thermal gradient from four in the forest of Okinawa Island to five in the forest of Ishigaki Island. The values of ShannonŐs index  and PielouŐs index  tended to increase from the top layer downward in the forest of Okinawa Island. However, in the forest of Ishigaki Island, these values tended to increase from the bottom layer upward. High woody species diversity depended on small-sized trees in the forest of Okinawa Island, whereas it depended on large-sized trees in the forest of Ishigaki Island. The forest of Okinawa Island (= 4.83 bit) showed higher woody species diversity than the forest of Ishigaki Island (= 4.36 bit). According to successively decreasing height of layers from the top downward, the value of increased continuously from the top layer downward in the forest of Okinawa Island. This increasing trend was different from the forest of Ishigaki Island, where the value of  increased up to the second layer and then decreased downward. In the forest of Okinawa Island, the expected number of species increased continuously from the top toward the bottom layer, i.e. the bottom layer contained the highest potential number of species (65). However, in the forest of Ishigaki Island, it increased from the top to the fourth layer, and then decreased to the bottom layer, i.e. the fourth layer contained the highest potential number of species (90). The species composition in the forest of Okinawa Island was different from that in the forest of Ishigaki Island, though approximately half of the species were common between the forests. The highest degree of similarity in species composition was between the second and third layers in the forest of Okinawa Island, whereas it was between the third and bottom layers in the forest of Ishigaki Island. The degree of similarity in species composition between the top and the lower three layers was high in the forest of Okinawa Island, whereas it was very low between the top and the lower four layers in the forest of Ishigaki Island. Except the top and the bottom layer respectively for the forests of Okinawa Island and Ishigaki Island, the spatial distribution of trees was random in each layer. The degree of overlapping in the spatial distribution of trees among layers in the forests suggested that light can not penetrate easily to the lower layers. For both of the forests, mean tree weight of each layer decreased from the top toward the bottom layer, whereas the corresponding tree density increased from the top downward. This trend resembled the mean weightdensity trajectory of self-thinning plant populations.

 

 

Poster -14

 

Preliminary examination of zooxanthellate zoanthid (Hexacorallia, Zoantharia) and associated zooxanthellae (Symbiodinium spp.) diversity in Singapore

 

James Davis Reimer1, 2

 

1 Department of Chemistry, Biology and Marine Science, Faculty of Science,

University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan

2Research Program for Marine Biology and Ecology, Extremobiosphere Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan

 

The order Zoantharia (=Zoanthidea, Zoanthiniaria) remains one of the most taxonomically neglected and least examined orders of Cnidaria despite a worldwide distribution in marine environments. In particular, zooxanthellate zoanthids from the genera Palythoa (family Sphenopidae) and Zoanthus (Zoanthidae) are very common in tropical and subtropical shallow waters. Confusion surrounding the taxonomy and species diversity in these two families is largely attributable to the morphological plasticity (i.e. polyp shape and size, oral disk color, etc.) within species, the lack of accurate morphological markers to properly discern species, and the paucity of accurate species descriptions in past literature. However, recent examinations utilizing mitochondrial 16S ribosomal DNA (mt 16S rDNA), mitochondrial cytochrome oxidase subunit I (COI) and the internal transcribed spacer of ribosomal DNA (ITS-rDNA) data from Zoanthus and Palythoa spp. specimens from Japan combined with more traditional morphological methods have begun to bring taxonomic order to these two genera. Other studies utilizing ITS-rDNA from symbiotic zooxanthellae (Symbiodinium spp.) from these two genera have shown varying levels of symbiont specificity and flexibility between zoanthid species. Here, we utilize the ŇcombinedÓ molecular and morphological methodology to examine the species diversity of these two genera in the waters of Singapore. 44 zooxanthellate zoanthid specimens representing a wide range of morphotypes were collected from three locations (Raffles Lighthouse, Lazarus Island, Kusu Island) in November-December 2006. Upon collection, specimens were assigned tentative species identifications based solely on morphology. Further examinations of mt 16S rDNA, COI, as well as ITS-rDNA from Symbiodinium, allowed us to 1) identify specimens to the species level, and 2) examine the accuracy of morphological identifications. Our results show collected specimens represent five species of zooxanthellate zoanthids; Zoanthus sansibaricus (n=11), Zoanthus vietnamensis (n=17), Palythoa tuberculosa (n=13), Palythoa mutuki (n=2), and a potentially undescribed Palythoa species (n=1) closely related to Palythoa heliodiscus. Species identifications are somewhat tentative due to the almost complete lack of previous reports of zoanthids in Singapore. Based on morphology alone, we were able to identify only 35 of 44 specimens (=80%) correctly. Acquired Symbiodinium ITS-rDNA sequences reflect previously seen patterns of association in Zoanthus, with Zoanthus sansibaricus (Symbiodinium subclade C1z) and Zoanthus vietnamensis (C15-related) both showing identical zooxanthellae types as seen in Japan and other Indo-Pacific locations. Unexpectedly, the majority of Palythoa tuberculosa (n=9) associated with Symbiodinium clade E, not previously seen in zoanthids, and only a few specimens (n=4) associated with clade C1/C3 as observed in most previous studies. The results of this study highlight the need for further sampling and examination of zooxanthellate zoanthids from other locations to help complete the global picture of zoanthid and associated zooxanthellae distribution patterns and diversity.

L to R; potential new Palythoa species, Zoanthus vietnamensis, and Palythoa tuberculosa.


Edited by:

Hidetoshi Ota and Peter A. Todd