Nanorana laojunshanensis Tang, Liu & Yu, 2023

The case of Nanorana laojunshanensis Tang, Liu & Yu, 2023 and another new taxon of the genus.

Tang et al. (2023) described N. laojunshanensis from the Hengduan Mountains in Yunnan province, China, as the sister lineage of the lineage leading to Nanorana pleskei Günther, 1896 and Nanorana ventripunctata Fei & Huang, 1985 . Morphologically, N. laojunshanensis exhibits a distinct combination of characteristics from known congeners, such as the presences of a tympanum, equal lengths of fingers I and II, a small body size, a yellow ventral surface of limbs, distinct vomerine teeth, indistinct subarticular tubercles, a head width greater than head length, slender supratympanic fold, the absence of the dorsolateral fold, the presence of nuptial spines on fingers I and II in adult males, the absence of a vocal sac, and paired brown spines on the chest. Within the nominal subgenus Nanorana , this new taxon is distinguished by indistinct subarticular tubercles and by “ lacking dark blotches on ventral surface and ventral surface of limbs yolk yellow ” ( Tang et al. 2023).

Coincidently   GoogleMaps , another species, Nanorana huangi Ji, Shi, Ma, Shen, Chang & Jiang, 2023 , was described from the exact same area and published by a different team ( Ji et al., 2023) during the same period ( Autumn   GoogleMaps 2023). The   GoogleMaps type locality of N. huangi (26.874593° N, 99.544008° E; 3389 m a. s. l) is distanced by only about 30 km (by air line; Fig. 1C View Figure ) from the type locality of N. laojunshanensis ( Mt. Laojun   GoogleMaps , Lijiang   GoogleMaps , Yunnan, China; 26°37’ N, 99°42’ E, 3982 m a.s.l.) and both populations are morphologically similar. In   GoogleMaps this respect, the morphological assessment of N. huangi is based on a greater sample size than N. laojunshanensis , and accordingly captures higher intraspecific variability (particularly for quantitative traits), which challenges the characteristics previously reported as diagnostic for N. laojunshanensis (e.g., body size, shape of supratympanic fold, coloration). Our   GoogleMaps re-analysis of 16S and COI also reveals strong similarities, with both species sharing identical or closely related haplotypes ( Fig. 1A, B View Figure ) with low level of genetic diversity (π= 0.2 %), and we therefore consider N. huangi and N. laojunshanensis as subjective synonyms ( Fig. 1A, B View Figure ). Since   GoogleMaps the description of N. huangi was published on September 28, 2023, [vs. November 7, 2023, for N. laojunshanensis ], N. huangi is treated as the oldest available name. The   GoogleMaps genetic distances highlighted by Tang et al. (2023) to justify the split of the new taxon from its closest relatives N. ventripunctata and N. pleskei , are relatively low, namely 1.6 % for 16S and 7.4 % for COI, suggesting a young divergence (see also comment in Dufresnes and Litvinchuk 2022). These   GoogleMaps distances are typically lower than those presented for other species of the genus at the same loci (i.e., Liu et al. 2021). In   GoogleMaps addition, the study lacks a comparative analysis for a nuclear, biparentally inherited marker alone, although sequences of the nuclear gene RAG1 were included. Given   GoogleMaps the relatively low observed genetic distances for the mtDNA markers, we expect the RAG1 variability in the investigated sequences between taxa to be also low. Here, we found little differentiation in RAG1 (for comparison with other species pairs, see Hofmann et al. 2023a), namely 0.18 % between N. laojunshanensis and N. pleskei , 0.43 % between N. laojunshanensis and N. ventripunctata , and 0.18 % between N. pleskei and N. ventripunctata (all individual sequences were homozygous). Besides, the sequence KY172605 View Materials specified by the authors in their RAG1 dataset is a tyrosinase fragment. Drawing from these points, we advise caution towards the distinction of N. huangi as a separate species (see the topology in Fig. 1 View Figure ) without additional genetic (ideally genomic) evidence. This example is paradigmatic of hasty species descriptions and represents a certain trend observed in current taxonomic research that is not always beneficial for taxonomy/species conservation itself.