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