Last exit before the brink: Conservation genomics of the Cambodian population of the critically endangered southern river terrapin.

The southern river terrapin, Batagur affinis is one of the world's 25 most endangered freshwater turtle species. The major portion of the global population is currently found in peninsular Malaysia, with the only remnant Indochinese population in southern Cambodia. For more than a decade, wild nests in this remnant Cambodian population have been fenced and hatchlings reared in captivity. Here we amplified 10 microsatellite markers from all 136 captive individuals, obtained 2,658 presumably unlinked and neutral single nucleotide polymorphisms from 72 samples with ddRAD-seq, and amplified 784 bp of mtDNA from 50 samples. Our results reveal that the last Indochinese population comprised only four kinship groups as of 2012, with all offspring sired from <10 individuals in the wild. We demonstrate an obvious decrease in genetic contributions of breeders in the wild from 2006-2012 and identify high-value breeders instrumental for ex-situ management of the contemporary genetic stock of the species.

DISEASE SCREENING IN SOUTHERN RIVER TERRAPINS ( BATAGUR AFFINIS EDWARDMOLLI) IN CAMBODIA.

Southern River terrapins ( Batagur affinis) are among the most critically endangered turtles in the world. To augment the Cambodia population, a head-start program was established for the endemic subspecies Batagur affinis edwardmolli in 2006, and in 2015, prerelease health assessments were performed on 70 subadults (hatch years, 2006-2011). Combined choanal/cloacal swab samples ( n = 70) were collected and screened by polymerase chain reaction (PCR) for Mycoplasma, herpesvirus, and ranavirus. Cloacal samples ( n = 50) were also collected and cultured for Salmonella sp. Of 70 tested samples, six (8.6%) were positive for Mycoplasma, and all other PCR and culture test results were negative. Phylogenetic analysis of the 16S ribosomal RNA gene placed the Mycoplasma sp. from B. affinis edwardmolli in the chelonian Mycoplasma cluster that groups within the Mycoplasma pulmonis clade. This mollicute was not associated with clinical disease (defined as observable clinical abnormalities, such as depression, lethargy, respiratory signs, and anorexia) and is likely part of the endemic microbial flora of these terrapins.