# Revisiting the Species Delimitation Within Amolops mantzorum (David, 1872), with a Description of a New Subspecies (Anura, Ranidae)

## TL;DR

This study identifies a new subspecies of the Sichuan torrent frog, clarifying its taxonomy and emphasizing the importance of accurate species delimitation for conservation.

## Contribution

The discovery and description of a new subspecies of Amolops mantzorum, supported by mitochondrial phylogeny and morphological analysis.

## Key findings

- A new subspecies, Amolops mantzorum feiye, was identified based on mitochondrial and morphological data.
- Four distinct lineages within A. mantzorum were clearly divided for the first time using phylogenetic analysis.
- Morphometric differences confirmed the uniqueness of the Yalong River population compared to existing subspecies.

## Abstract

Currently, controversy about the intraspecific taxonomy of Amolops mantzorum remains unresolved. The Litang population was overlooked for several years in recent phylogenetic studies. We revisited this population and described the third subspecies of A. mantzorum, clearly dividing the four recognized lineages within A. mantzorum for the first time based on mitochondrial phylogeny. Our findings highlighted the importance of clear delimitation and naming of subspecies for biological conservation and taxonomic description, and provided insights for future investigations into the taxonomy of the Amolops mantzorum species group.

Accurate species delimitation benefits detailed biological descriptions and conservation practices. In this study, we focus on a frog species distributed throughout the western edge of Sichuan Basin, China, the Sichuan torrent frog—Amolops mantzorum. Currently, A. mantzorum is recognized as comprising two subspecies—the nominate subspecies A. m. mantzorum and A. m. xinduqiao. We investigated a population from along the Yalong River, Sichuan Province, China which was previously overlooked in phylogenetic studies. Combining multiple mitochondrial genes (16S, CO1, cytb), we identified four distinct lineages within A. mantzorum using Bayesian inference and maximum likelihood phylogeny. Principal Component Analysis based on morphometrics revealed significant differences between the population from along the Yalong River and the other two subspecies for which morphological data were available. Combined with detailed morphological descriptions and comparisons, here we describe this population as the third subspecies of A. mantzorum—Amolops mantzorum feiye ssp. nov.