# Museum Specimens Reveal the Taxonomic Distinctions Among South Asian Treeshrews

## TL;DR

This study uses museum specimens to clarify the taxonomic distinctions among South Asian treeshrew species based on morphological analysis.

## Contribution

The study provides new morphological evidence supporting species differentiation and synonymy among South Asian treeshrews.

## Key findings

- Three treeshrew species show clear cranial differentiation despite slight morphospace overlaps.
- Five subspecies of T. belangeri and two of A. ellioti are synonymized based on morphological data.
- Diagnostic traits enhance understanding of treeshrew taxonomy in South Asia.

## Abstract

South Asian treeshrews include the Madras Treeshrew
Anathana ellioti
, the Northern Treeshrew
Tupaia belangeri
, and the Nicobar Treeshrew
Tupaia nicobarica
, each occupying distinct and non‐overlapping geographical areas in India and Southeast Asia. In this study, we investigated the morphological variation among these species using museum specimens collected over a wide spatial and temporal range of India and Myanmar and combined with existing published datasets. We analyzed 22 cranial measurements and four external traits to evaluate inter‐ and intraspecific morphological differentiation, employing distance‐based morphometric approaches validated by multivariate analyses. Our findings revealed considerable heterogeneity in cranial morphology, with three species exhibiting clear differentiation, despite slight overlaps in morphospace. Furthermore, our results support the synonymy of the five previously recognized allopatric subspecies of
T. belangeri
and the two subspecies of
A. ellioti
. The additional diagnostic characteristics identified in this study enhance the understanding of morphological distinctions among the South Asian treeshrews and contribute to broader taxonomic knowledge of treeshrew diversity.

In this study, we investigated the morphological relationships among the treeshrew species found in South Asia using museum specimens collected over a wide spatial and temporal range in India and Myanmar, combined with existing published datasets, contributing to broader taxonomic knowledge of treeshrew diversity.