2004

Asiatic Herpetological ResearchVol. 10, pp. 22-27

Rediscovery of the Philippine Forest Turtle, Heosemys leytensis(Chelonia; Bataguridae), from Palawan Island, Philippines
ARVIN C. DIESMOS1,2,3, GENEVIEVE V. A. GEE3, MAE L. DIESMOS3, 4, RAFE M. BROWN2,3,5,
PETER J. WIDMANN3,6, AND JUDELINE C. DIMALIBOT7
1National Museum of the Philippines, Padre Burgos Avenue, Ermita 1000, Manila, Philippines;

Current address: Department of Biological Sciences, National University of Singapore,
Block S3 14 Science, Drive 4, Singapore 117543; E-mail: kaloula@i-manila.com.ph
2Angelo King Center for Research and Environment Management; Marine Laboratory,
Silliman University, Bantayan, Dumaguete City, Negros Oriental, Philippines 6200.
3Wildlife Conservation Society of the Philippines, Room 106 Institute of Biology, University of the Philippines,
Diliman 1101, Quezon City, Philippines; E-mail: jutisha@yahoo.com
4Department of Biological Sciences, College of Science, University of Santo Tomas
España, Manila; E-mail: msleonida@lycos.com
5Section of Integrative Biology, University of Texas, Austin Texas, 78712;
Current address: Museum of Vertebrate Zoology, 3101 Valley Life Science Building,
University of California, Berkeley, CA 94720; Email: rafe@mail.utexas.edu
6KATALA Foundation, Jacana Road, Bancao-Bancao, P.O. Box 390, Puerto Princesa City 5300,
Palawan, Philippines; E-mail: widpeter@yahoo.com
7Palawan Council for Sustainable Development, Sta Monica, Puerto Princesa City 5300,
Palawan, Philippines.
Abstract. - We report new observations from natural populations of the critically endangered Philippine forest turtle,
Heosemys leytensis. Previously known from two cotypes (reportedly from Leyte Island) that were destroyed during
World War II, a lone specimen in a U.S. collection, and a specimen purchased on Palawan Island in the late 1980s,
its status in the wild has been uncertain since its discovery. Our recent surveys of Palawan and nearby Dumaran
islands have documented natural populations that are under immediate threat due to over-harvesting and loss of habitat. Records of captive animals and interviews with residents from these islands suggest that this species is heavily
exploited for food, pet trade, and ornamental fish pond curiosities. There is an urgent need to establish a conservation
program to study and protect remaining natural populations.
Key words. - Heosemys leytensis, Asian freshwater turtles, turtle trade, Philippine forest turtle, Palawan Island,
Philippines.

Introduction
Taylor (1920) described the Philippine forest turtle,
Heosemys leytensis, on the basis of two specimens thatwere collected by Gregorio Lopez. These specimens
were reportedly collected from a swamp at theMunicipality of Cabalian, southern Leyte Province,
Leyte Island, Philippines (Fig. 1). The cotypes (a maleand a female) were eventually deposited in thePhilippine Bureau of Science (Taylor, 1944) but weredestroyed during the World War II firebombing of
Manila (Brown and Alcala, 1978; Buskirk, 1989).
Between Taylor’s (1920) description and the late1980s, no additional specimens or information became
available for this species, although its status as a valid
species has never been challenged (e.g., Pritchard, 1979;© 2004 by Asiatic Herpetological Research

Ernst and Barbour, 1989; Iverson, 1992). In 1988,
Timmerman and Auth reported on a specimen purchasedfrom a local resident of the Municipality of Taytay,
northern Palawan Island (Fig. 1). Buskirk (1989)
described a neotype for the species (CAS 60930) basedon a single specimen also reportedly from Cabalian,
Leyte.
Since these reports, numerous herpetologists,
including us, have searched for H. leytensis at Cabalian,
Leyte (Fig. 1) without success. The apparent rarity of thespecies formed the basis of its listing under CITES
Appendix II and by IUCN as a Critically Endangered
species (Hilton-Taylor, 2000). Chelonian biologists
questioned whether the species was really rare or justunstudied, extinct or extirpated, and whether the specimen reported by Timmerman and Auth (1988) was from

Vol. 10, p. 23

Asiatic Herpetological Research

Figure 1. - Map of Palawan Island group in relation to thePhilippines (inset) and Leyte Island. The type locality(Taylor, 1920) of H. leytensis is indicated with a star;recent trade or captive animal locations include (1)Brooke’s Point, (2) Rizal, (3) Aborlan, and (4) Puerto
Princesa and known natural populations include (5)Taytay, and (6) Dumaran Island.

a natural population on Palawan or the result of interisland trade (Ernst and Barbour, 1989; Iverson, 1992; Das,
1995; Gaulke, 1995). The question remained whether H.
leytensis occurred on Leyte Island or whether the original type locality data were in error.
In late 2001, as part of a comprehensive statusassessment of Palawan’s endemic amphibians and reptiles, we began a survey of forested sites throughout theisland. We soon became aware of three nonmarine turtle species present in some local wet markets and in thepossession of local wildlife traders. Two species Cuora
amboinensis and Cyclemys dentata, are common on
Palawan (Taylor, 1920; Alcala, 1986; Gaulke and Fritz,
1998; Widmann, 1998; ACD and RMB, pers. obs.). A
third species, frequent in the wildlife and food trade, wasidentified as Taylor’s (1920) Heosemys leytensis.
New observations. - The live specimens we examinedmatch published descriptions of H. leytensis (Taylor,
1920; Buskirk, 1989; Ernst and Barbour, 1989): carapace unkeeled except for posterior vertebrals; vertebrals
broader than long; anterior marginals projecting beyond
cervicals, rendering anterior rim from slightly to strongly serrated; plastron much smaller than carapace, nar-

2004

Figure 2. - Live H. leytensis from natural population on
Dumaran Island, northern Palawan: (A) An individual ofundetermined sex in a small stream on Dumaran Island;(B) close up of the head.

rowing anteriorly and posteriorly; angular notch
between gulars deep and distinct; notch between gulars
and humerals present, less distinct; anal notch deep andcircular; three to four enlarged transverse scales present
on anterior side of each foreleg; coloration rusty brownwith darker margins on anterior scutes; narrow white topale yellow line crosses head just behind auricular openings, medially divided in some specimens (Figs. 2-5). A
full technical redescription of the morphology of H.
leytensis will be published elsewhere (Diesmos et al.,unpublished data).
We located captive animals for sale in markets at
the Municipalities of Brookes Point, Aborlan, Rizal,
Puerto Princesa City, and Taytay (Fig. 1). The animals
were for sale as pets, ornamental fish pond curiosities,
and for food. Additionally, H. leytensis individuals were
found in public restaurants in the capital city of Puerto
Princesa (Fig. 4b). In many areas, residents expressed
the belief that the keeping of pet H. leytensis specimens
brings the owner good luck.
We found natural populations in the vicinity of Lake
Manguao, Municipality of Taytay, Palawan Island andon Dumaran Island (Fig. 2). Exact localities are notgiven to protect these populations. Several individualsof each natural population were observed in slow-mov-

2004

Asiatic Herpetological Research

Figure 3. - (A) Dorsal view of carapace and (B) ventral
view of plastron of a subadult H. leytensis of undertermined sex (captive pet, reportedly wild-caught locally)
from Dumaran Island, N. Palawan.

ing streams, quiet side pools, and nearby disturbed
gallery forests (Fig. 4a), at most a few meters from thewater’s edge. Residents in these localities reported to us
that turtles are always located in the general vicinity ofwater, but that they can be found many meters awayfrom water as well. Residents also report that H. leytensis burrows in stream banks and retreats under large
nearby limestone boulders in the dry season when
streambeds run dry.
Interviews with Tagbanwa tribe members in the
Municipality of Taytay suggest that in some areas thisspecies is fairly common. Reports of natural populations in the southern localities of Rizal and Brookes
Point will need to be confirmed. In these areas interviewed persons claimed that H. leytensis was present innearby forests but we were unable to locate wild animals
ourselves.

Discussion
Our recent field observations confirm that H. leytensis
occurs naturally on Palawan and at least on one of its
northern satellite islands. Despite numerous surveys ofsuitable habitat at Cabalian, Leyte conducted by E.

Vol. 10, p. 24

Figure 4. - (A) Preferred stream habitat of H. leytensis
from Dumaran Island, northern Palawan; (B) Heosemys
leytensis, Cuora amboinensis, and Cyclemys dentata
specimens alive in captivity in restaurant of Puerto
Princesa City, Palawan Island.

Taylor, A. Alcala, and ourselves, no additional specimensof H. leytensis have been collected there. Interviews
with residents in the vicinity of Cabalian, have failed tofind verbal accounts of fresh-water turtles that fit thedescription of H. leytensis. We suspect that the species
does not and never has naturally occurred on Leyte. We
prefer the use of the common name “Philippine forest
turtle” given that we have only observed animals in remnant old-growth forests and our sense is that this species
is forest dependent.
It is possible that Taylor or Lopez mislabeled or otherwise confused locality information assigned to theoriginal co-types on Leyte and the third specimen at
CAS (Buskirk, 1989). Taylor (1920) also reported
Cyclemys dentata from Cabalian, Leyte (see also
Iverson, 1992). This species has not since been reported
from Leyte and is otherwise restricted in the Philippines
to Palawan and the Sulu archipelago (Fig. 1; Taylor,
1920; Gaulke, 1995; Gaulke and Fritz, 1998). The factthat another conspicuous Palawan turtle species wasreported at the same time and from the same site on
Leyte (Taylor, 1920) suggests that a group of specimensfrom Palawan were mixed into collections from Leyte orVol. 10, p. 25

Asiatic Herpetological Research

2004

Figure 5. - A live Heosemys leytensis from the Municipality of Taytay, northern Palawan Island, Philippines.
Watercolors by Mr. Rene Aquino.

were mislabeled. Based on information from the CAS
herpetological registry, it is clear that G. Lopez also collected on Coron and Busuanga (Fig. 1) which would
appear to be a likely source of the presumably erroneous“Leyte” specimens of C. dentata and H. leytensis. Thus,
we suspect that a locality error is the basis of the specific epithet and the long-held belief that H. leytensis naturally inhabits the island of Leyte. Whether H. leytensis
has ever been introduced outside of Palawan or thecountry, remains to be documented.
Finally, given the geological history and the
Pleistocene formation of isolated paleoislands in thePhilippines (Heaney, 1985; Hall, 1996, 1998) it is not
surprising that H. leytensis may be restricted to Palawan
and satellite islands. Based on available informationfrom other groups of Philippine endemics, it is somewhat rare for a species to be shared between both the
Palawan (Palawan + Busuanga + Coron + Culion +Dumaran) and the Mindanao (Mindanao+Bohol+Leyte+
Samar) Pleistocene Aggregate Island Complexes(PAICs). That is, based on previously-elucidated patterns of biogeography (Brown and Alcala, 1970; Brown

and Diesmos, 2001; Brown and Guttman, 2002; Evanset al., 2003), we would expect to find Philippine
endemics with restricted distributions on the Palawan
PAIC or the Mindanao PAIC, but not necessarily both.
There are some exceptions to these apparent trends, butthey appear to be rare and limited to non-endemic widespread species that are also shared with the islands of the
Sunda Shelf (Borneo, Java, Sumatra, etc.), or widespread Philippine endemics that are also found throughout the rest of the archipelago (Inger, 1954; Alcala and
Brown, 1998; Brown and Alcala, 1970, 1978, 1980)
Recommendations. - We recommend that an immediate
exhaustive survey of the Palawan PAIC (including
Balabac, Coron, Busuanga, Culion, and Dumaran) be
undertaken to determine the status of natural H. leytensis populations. Basic knowledge of the species’ distribution, habitat requirements, and natural population size
will be a necessary requirement for designing effective
conservation strategies. To combat illegal hobbyist, consumptive, and/or medicinal trade, wildlife managers willneed to have reasonable estimates of numbers of animals

2004

Asiatic Herpetological Research

Table 1. - Standard measurements of H. leytensis specimens from captivity (Nos. 1-20) and a natural population(Nos. 21-24; Dumaran Isl.). Carapace Length and Width
are straight-line distances; Carapace Width measured atwidest point; Tail Length measured from posterior edgeof cloaca to tip of tail. Sex undetermined; all measurements are in mm.
Number Carapace Carapace Plastron Tail Length
LengthWidth
Length
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.

177.0
183.8
189.6
192.5
192.7
196.4
200.1
203.6
210.2
215.9
222.3
231.2
248.5
261.7
266.3
269.9
271.7
275.3
278.0
280.0
290.6
297.8
299.6
299.9

134.3
139.6
144.5
142.4
148.4
152.2
148.1
151.8
157.3
160.8
171.2
172.2
191.5
191.0
195.5
196.4
198.3
200.5
200.4
201.6
207.8
211.4
212.4
212.9

153.8
151.6
157.2
158.1
150.8
151.4
165.9
171.4
118.1
179.7
186.6
185.2
206.8
210.3
201.5
213.0
206.7
205.6
208.9
205.2
216.3
208.5
212.1
213.0

15.9
17.6
19.8
18.3
19.1
20.4
22.2
19.2
35.6
19.9
35.1
22.8
18.6
25.5
26.2
23.4
21.7
19.7
27.1
29.1
27.7
30.9
28.2
35.0

being illegally harvested. Legislative protection of thespecies will need to be adjusted to recognize its current
known distribution on Palawan and not Leyte. We
expect that a specific conservation strategy will be necessary to protect this species from unchecked exploitation. The fact that the entirety of Palawan is officiallydesignated a national protected area provides someassurance, but we suspect additional measures will need
to be undertaken to protect this species while promoting
its study. The legal “Protected Area” status of Palawan
Island clearly is not deterring local exploitation of thisspecies. Local education programs and public awarenesscampaigns targeting both the general public and local
environmental authorities may be the key to insuringthat H. leytensis does not become another casualty of the“Asian turtle crisis” (van Dijk et al., 2000). Many basic
questions regarding the distribution, demography, ecology, reproductive biology, and phylogenetic affinities of
H. leytensis remain to be answered.

Vol. 10, p. 26

Acknowledgments
This publication is a contribution of HerpWatch
Palawan 2001, a project funded by the BP Conservation
Programme (Silver Award No. 1554). ACD, MLD,
GVAG, and JCD wish to thank their former institutions
for supporting this work: De La Salle UniversityDasmariñas, Haribon Foundation, and Palawan State
University. The Protected Areas and Wildlife Bureau of
the Philippine Department of Environment and Natural
Resources and the Palawan Council for Sustainable
Development facilitated research permits. We especiallythank Althea Lota, Anson Tagtag, Marlynn Mendoza,
Carlo Custodio, Mundita Lim, Wilfrido Pollisco, Linda
Bacosa, Joselito Alisuag, Adelwisa Sandalo, and Rene
Villegas. Indira Widmann, Siegfred Diaz, Deborah
Villafuerte, Rolito Dumalag (Philippine Cockatoo
Conservation Project), and Sabine Schoppe (State
Polytechnic College of Palawan) extended much appreciated assistance and shared relevant information. We
thank C. R. Infante for help during initial field survey
work on Palawan and I. Das and M. Gaulke for providing some critical reference material. We thank James
Parham (University of California, Berkeley) and Bryan
Stuart (Field Museum, Chicago) for providing references and for applying just the right amount of pressure
to help us finish this report, and we thank Greg Pauly,
Jen Weghorst, George Zug, and Bryan Stuart for criticalreviews of earlier drafts of the manuscript. Special
thanks are due to Rene Aquino (National Museum of thePhilippines) for use of his painting of H. leytensis in life.

Literature Cited
Alcala, A. C. 1986. Guide to Philippine Flora and Fauna.
Vol. X, Amphibians and Reptiles. Natural Resource
Management Center, Ministry of Natural Resources
and the University of the Philippines, Manila,
Philippines.
Alcala, A. C., and W. C. Brown. 1998. Philippine
Amphibians: an Illustrated Field Guide. Bookmark
Press, Makati City, Philippines.
Brown, R. M., and A. C. Diesmos. 2001. Application of
lineage-based species concepts to oceanic island
frog populations: the effects of differing taxonomic
philosophies on the estimation of Philippine biodiveristy. The Silliman Journal 42:133-162.
Brown, R. M., and S. I. Guttman. 2002. Phylogenetic
systematic of the Rana signata complex ofPhilippine and Bornean stream frogs; reconsidera-

Vol. 10, p. 27

Asiatic Herpetological Researchtion of Huxley’s modification of Wallace’s Line at
the Oriental-Australian faunal zone interface.
Biological Journal of the Linnean Society 76:393461.
Brown, W. C., and A. C. Alcala. 1970. The zoogeography of the Philippine Islands, a fringing archipelago. Proceedings of the California Academy of
Science 38:105-130.
Brown, W. C., and A. C. Alcala. 1978. Philippine
Lizards of the Family Gekkonidae. Silliman
University Press, Dumaguete City, Philippines.
Brown, W. C., and A. C. Alcala. 1980. Philippine
Lizards of the Family Scincidae. Silliman
University Press, Dumaguete City, Philippines.
Buskirk, J. R. 1989. A third specimen and neotype of
Heosemys leytensis (Chelonia: Emydidae). Copeia
1989:224–227.
Das, I. 1995. Status of knowledge on the biology andconservation of non-marine turtles of thePhilippines. International Congress of Chelonian
Conservation, Gonfaron, France.
Ernst, C., H., and R. W. Barbour. 1989. Turtles of theworld. Smithsonian Institution Press, Washington,
DC.
Evans, B. J., R. M. Brown, J. A. McGuire, J. Supriatna,
N. Andayani, A. C. Diesmos, D. Iskandar, D. J.
Melnick, and D. C. Cannatella.
2003.
Phylogenetics of fanged frogs: testing biogeographical hypotheses at the interface of the Asian andAustralian faunal zones. Systematic Biology
52:794-819.
Gaulke, M., 1995. On the distribution of emydid turtles
and the anuran genus Microhyla in the Philippines.
Asiatic Herpetological Research 6: 49-52.
Gaulke, M. and U. Fritz. 1998. Distribution patterns ofbatagurid turtles in the Philippines. Herpetozoa
11:3-12.
Hall, R. 1996. Reconstructing Cenozoic SE Asia. Pp.
153-184 In: Tectonic evolution of southeast Asia.
Hall, R., and D. Blundell (eds). Geological Society,London.
Hall, R. 1998. The plate tectonics of Cenozoic SE Asiaand the distribution of land and sea. Pp 99-132 In:

2004

Biogeography and geological evolution of southeast
Asia Hall, R., and J. D. Holloway (eds). Brackhuys,
Leiden.
Heaney, L. R. 1985. Zoogeographic evidence for middle
and late Pleistocene land bridges to the Philippines.
Modern Quaternary Research of SE Asia 9:127143.
Hilton-Taylor, C. (Compiler) 2000. 2000 IUCN Red Listof Threatened Species. IUCN, Gland, Switzerland
and Cambridge.
Inger, R. F. 1954. Systematics and zoogeography ofPhilippine Amphibia. Fieldiana 33:181-531.
Iverson, J. B. 1992. A revised checklist with distribution
maps of the turtles of the world. Privately published, Richmond, IN.
Pritchard, P. C. H. 1979. Encyclopedia of turtles. TFH
Publications, Neptune, NJ.
Taylor, E. H. 1920. Philippine turtles. Philippine Journalof Science 16:111–144.
Taylor, E. H. 1944. Present location of certain herpetological and other type specimens. University of
Kansas Science Bulletin 30, No. 11:160
Timmerman, W. W., and D. L. Auth. 1988. Geographic
distribution: Heosemys leytensis. Herpetological
Review 19:21.
van Dijk, P. P., B. L. Stuart, and A. G. J. Rhodin. 2000.
Asian Turtle Trade. Proceedings of a Workshop on
Conservation and Trade of Freshwater Turtles andTortoises in Asia. Chelonian Research Monographs,
2.
Widmann, P. 1998. A Guide to the Ecosystems of
Palawan Philippines. ViSCA-GTZ and Times
Edition, Singapore.