Nanorana bangdaensis Rao, Hui, Zhu & Ma, 2022

The additional case of Nanorana bangdaensis Rao, Hui, Zhu & Ma, 2022

In addition to the above-mentioned four cases, our re-analysis of the 16S data available on GenBank also offer the opportunity to discuss the status of the recently described N. bangdaensis Rao, Hui, Zhu & Ma, 2022 , which is nested within Nanorana parkeri ( Stejneger, 1927) ( Fig. 1A, D View Figure ). Since the sequences of the latter originated from very different localities across the Tibetan Plateau ( Fig. 1E View Figure ), we suspect that N. bangdaensis might be conspecific with N. parkeri . This alpine species has been intensively studied by population genomics and standard single barcoding-gene approaches using sampling that covers its entire distribution range ( Zhou et al. 2014, Wang et al. 2018). These studies revealed major populations [(E)ast and (W)est], defining them as evolutionarily significant units, and up to four subpopulations (E1-E4) with only low whole-genomic differentiation among them. A similar east-west population structure has been previously identified in the endemic Tibetan snake Thermophis baileyi (Wall, 1907) ( Hofmann et al. 2014) , consistent with a scenario of range expansion from different refugia during interglacial and post-glacial times. Since one of the eastern N. parkeri subpopulation (E4; KJ811207 and KJ811261 ) corresponds to the type locality of N. bangdaensis ( Bangda , [Baxoi County], Qamdo Prefecture , Tibet Autonomous Region, China), we used the COI-sequence data of N. bangdaensis and of the N. parkeri (sub)populations W and E1 ― E4, comprehended by N. bangdaensis / N. parkeri sequence data of Ji et al. (2023) and Tang et al. (2023), to assess their respective sequence divergence ( Fig. 1D, E View Figure ). As suspected, the COI sequences of N. bangdaensis are identical to sequences representatives of the East lineage of N. parkeri suggesting that N. bangdaensis and N. parkeri are weakly differentiated and likely belong to the same species. The lack of clear morphological diagnostic features further supports this assessment (https://www.amphibiachina.org as cited from Rao et al. 2020; original in Chinese : “ The length of the head is approximately equal to the width of the head; the tympanic membrane is not obvious; the skin on the back is smooth, with a few short warts or skin folds on the back; the back is gray-green in life, with no obvious dark spots; the sides of the body are light in color, mixed with irregular spots. ”). While examples of “super-cryptic species” (i.e., cryptic species that experienced a mitochondrial capture, thus necessitating nuclear data for their detection; Dufresnes et al. 2019) do exist, and notwithstanding the possibility for an unusually young speciation event, it appears more parsimonious to assume that N. bangdaensis is part of the high intraspecific variability of N. parkeri , and might either be synonymized or be distinguished as a subspecies (see genetic distances, Fig. 1D View Figure ).