|Batagur affinis affinis (Cantor, 1847) || เต่ากระอาน, River Terrapin|
Batagur affinis edwardmolli Praschag, Holloway, Georges, Päckert, Hundsdörfer & Fritz, 2009
|| เต่ากระอานเขมร, Cambodian River Terrapin
(c) west coast form of B. affinis, male, Klong La-ngu River, Satun Province, Thailand – photo: B. Horne; (d) west coast form of B. affinis, female, Perak River, Malaysia – photo: E.O. Moll;
(e) east coast form of B. affinis, male, Dungun River, Malaysia – photo: E.H. Chan; (f) east coast form of B. affinis, female, Terengganu River, Malaysia – photo: E.O. Moll; (g) Cambodian Batagur male, Sre Ambel River system, Cambodia – photo: R. Holloway; (h) Cambodian Batagur female, Sre Ambel River system, Cambodia – photo: B. Horne.
Note differences in head shape, soft part and iris coloration.
Estuarine Batagur are among the most critically endangered chelonian species. We assess the taxonomic status of the recently discovered Cambodian relic population of Batagur by phylogenetic analyses of three mitochondrial (2096 bp) and three nuclear DNA fragments (1909 bp) using sequences from all other Batagur species and selected allied geoemydids. Furthermore, we calculated haplotype networks of the mitochondrial cytochrome b gene for Cambodian terrapins, B. affinis, B. baska, and B. kachuga and compare external morphology of estuarine Batagur populations. Genetically, Cambodian Batagur are closely related with, but distinct from B. affinis from Sumatra and the west coast of the Malay Peninsula. Morphologically, Cambodian Batagur resemble the distinctive B. affinis populations from the eastern Malay Peninsula that were not available for genetic study. We suggest that the Batagur populations from the eastern Malay Peninsula and Cambodia represent a new subspecies of B. affinis that once was distributed in estuaries surrounding the Gulf of Thailand (Batagur affinis edwardmolli subsp. nov.). Its patchy extant distribution is most probably the result of large-scale habitat alteration and century-long overexploitation. In addition, our phylogenetic analyses suggest repeated switches between riverine and estuarine habitats during the evolution of the extant Batagur species.
Key words: Southeast Asia, South Asia, Batagur affinis affinis, Batagur affinis edwardmolli subsp. nov., Batagur baska, Batagur kachuga, endangered species
Batagur affinis edwardmolli
Etymology. The new subspecies is named in recognition of Professor Edward O. Moll, one of the foremost experts on river turtles, who substantially contributed to the knowledge of Batagur affinis and its natural history.
Diagnosis. Adults differ from nominotypical subspecies of Batagur affinis by their distinctly more
elongated head with upturned snout; males with chocolate brown to almost black head (east coast of peninsular Malaysia) or sometimes rusty brown to reddish head (Sre Ambel River system, Cambodia), edges of mouth orange; iris golden or bright yellow. Females and juveniles with conspicuous whitish grey to silvery blotches in temporal and parietal region; hatchlings with distally yellow marginal scutes. For corresponding characters of B. a. affinis, see Table 2.
Description of holotype. Specimen slightly macerated; some epidermal scutes detached from shell. Carapace roundish when viewed from above, with weakly serrated central and posterior marginal scutes; medial keel distinct, with posteriorly directed, slightly pointed spines. Plastron anteriorly truncated, posteriorly with anal notch. Straight line carapace length approximately 86 mm, carapace width 84 mm; medial plastron length 74 mm, maximum plastron length (to tips of anal scutes) 78 mm.
Range: East coast of peninsular Malaysia and adjacent Thailand; Sre Ambel River system, Cambodia (Fig. 5).
Peter Praschag, Rohan Holloway, Arthur Georges, Martin Päckert, Anna K. Hundsdörfer and Uwe Fritz. 2009. A New Subspecies of Batagur affinis (Cantor, 1847), One of the World’s Most Critically Endangered Chelonians (Testudines: Geoemydidae). Zootaxa. 2233: 57–68.