Tadpole identification and description of Marten’s Oriental Frog Occidozyga martensii based on marker 16S rRNA in Di Linh Plateau, Vietnam

Tóm tắt

The tadpole identification can support providing important information on the larval stage of amphibian species, which helps for studying the conservation, ecology, and life history of them. Based on morphological and molecular data, this study accurately identified the tadpoles of Marten’s Oriental Frog Occidozyga martensii which had been recorded in the Di Linh Plateau, Lam Dong province. These tadpole specimens were collected in the wet season, July and August 2022. Analyzing the morphology and molecule of the tadpoles, amplifying the 16S rRNA marker by using a pair of primers AH-16S_S and AH-16S_R. Their 16S rRNA sequences matched to those collected at the type locality of O. martensii in Bangkok (Thailand) and closely related to those of O. laevis collected in Philippines. The results provided detailed morphological description of O. martensii tadpoles at stage 37 and the morphological changes from stage 37 to 41, with diagnostic characteristics: upper fin originates far posterior to trunk-tail junction, at approximately 17% of tail length, with black short-stripes in front of eyes and black short-stripe behind mouth, brown belly with many white spots. The tadpole morphology of O. martensii most resembles tadpole of O. laevis when compared with all congeners in genus Occidozyga. O. martensii differs from O. laevis in only having black short-stripes in front of eyes. It is easily confused when identifying these two species by their morphological characteristics. However, the molecular data from this study and previous studies suggested that O. martensii is a different taxon from O. laevis. These results from this study indicated the necessity of molecular methods in the identification of amphibians. The morphological and molecular data of O. martensii tadpole are helpful for the next taxonomic studies and management of Oriental Frog Occidozyga species in the future.