Integrative Taxonomy of Southeast Asian Snail-Eating Turtles (Geoemydidae: Malayemys) Reveals a New Species and Mitochondrial Introgression

Abstract

Based on an integrative taxonomic approach, we examine the differentiation of Southeast Asian snail-eating turtles using information from 1863 bp of mitochondrial DNA, 12 microsatellite loci, morphology and a correlative species distribution model. Our analyses reveal three genetically distinct groups with limited mitochondrial introgression in one group. All three groups exhibit distinct nuclear gene pools and distinct morphology. Two of these groups correspond to the previously recognized species Malayemys macrocephala (Chao Phraya Basin) and M. subtrijuga (Lower Mekong Basin). The third and genetically most divergent group from the Khorat Basin represents a previously unrecognized species, which is described herein. Although Malayemys are extensively traded and used for religious release, only few studied turtles appear to be translocated by humans. Historic fluctuations in potential distributions were assessed using species distribution models (SDMs). The Last Glacial Maximum (LGM) projection of the predictive SDMs suggests two distinct glacial distribution ranges, implying that the divergence of M. macrocephala and M. subtrijuga occurred in allopatry and was triggered by Pleistocene climate fluctuations. Only the projection derived from the global circulation model MIROC reveals a distinct third glacial distribution range for the newly discovered Malayemys species.

Diversity of North American map and sawback turtles (Testudines: Emydidae: Graptemys)

“…It is obvious that such conflicts occur in taxa with weak genetic divergence having either wide and overlapping or abutting distributions ( G. ouachitensis , G. pseudogeographica , G. sabinensis ) or inhabiting neighbouring drainage basins ( G. flavimaculata , G. nigrinoda and G. oculifera ; G. ernsti , G. gibbonsi , G. pearlensis and G. pulchra ). The mitochondrial similarity of G. sabinensis to G. ouachitensis , despite being distinct in PCAs of nuclear data, suggests that mitochondrial introgression could play a role here, as known for many animal species (cf., for instance, the review in Currat, Ruedi, Petit, & Excoffier, ), among them also freshwater turtles (Fritz et al., ; Ihlow et al., ; Vamberger et al., ). Graptemys sabinensis and G. ouachitensis occur in neighbouring drainage basins (Figure ), and such introgression events could easily occur during flood events or stream capture.…”

The first complete mitochondrial genome of the Indian Tent Turtle, Pangshura tentoria (Testudines: Geoemydidae): Characterization and comparative analysis

“…Molecular data have been widely employed in Testudines systematics research and conservation genetics (Murphy et al, ; Spitzweg, Praschag, DiRuzzo, & Fritz, ). Mitochondrial genes, nuclear genes, and microsatellite marker have been used for identifying new species (Fritz et al, ; Ihlow et al, ), recognizing the genetic diversity and population structure (Fritz, Gemel, Kehlmaier, Vamberger, & Praschag, ), and estimating the phylogeny and evolutionary relationships of Testudines (Le, Raxworthy, McCord, & Mertz, ). Complete mitogenomes have also been examined to understand the evolution of Testudines and provide evidence to suggest a sister relationship between turtles and archosaurs among amniotes (Kumazawa & Nishida, ; Zardoya & Meyer, ).…”

Pet and turtle: DNA barcoding identified twelve Geoemydid species in northeast India

“…The utility of mtCOI gene also successfully tested to identify the Geoemydid species (Reid et al 2011;Kundu et al 2016). Therefore, having found the competency of this molecular tool in accurate species identification and delineation, it is essential to generate DNA barcode data (Ihlow et al 2016). The pet turtles are generally kept alive inside the small artificial water tank, barrel or aquarium without proper management and the shells are often intensely tinted by colours or chemicals for recreation purposes or high demanding commercial value.…”