[Mammalogy • 2024] Callosciurus concolor & Tamiops barbei • Lost in Synonymy: Integrative Species Delimitation reveals Two unrecognized Species of Southern Asian Tree Squirrels (Rodentia: Sciuridae: Callosciurinae)

  

 the skins of (A) Callosciurus caniceps (NHMUK 41.1817, lectotype);
live images of (B) C. caniceps caniceps taken by Natthaphat Chotjuckdikul (Te’) in Bangkok, Thailand;
(C) C. caniceps bimaculatus taken by Pattaraporn Vangtal in Railay Bay Beach, Krabi, Thailand; and
(D) C. concolor taken by Cheong Weng Chun in Fraser’s Hill, Pahang, Malaysia.

in Hinckley, Maldonado, Tamura, Leonard & Hawkins, 2024. 

DOI: doi.org/10.3897/vz.74.e133467

Abstract

We present a comprehensive integrative taxonomic review of Callosciurus caniceps and Tamiops mcclellandii as they are currently defined. This review combines published molecular evidence, craniodental morphometrics, pelage and bacular variation, evaluations of potential hybrid zones using museum specimens and citizen science photographs, and, for C. caniceps, bioacoustic evidence. Our findings lead to the recognition of two species that had been lost in synonymy and highlight future perspectives on species delimitation in Sciuridae. By comparing phenotypic differentiation across climatic and vegetation transitions and contextualizing our results with the evolutionary history of our study systems, we provide insights into distribution, ecogeographical patterns, and speciation drivers in Southeast Asian vertebrates.

Keywords: Baculum, bioacoustics, biodiversity, citizen science, Mammalia, morphometrics, Southeast Asia, speciation, taxonomy

Taxonomic revision: 

Based on our findings, which unite molecular phylogenetic (Hinckley et al. 2023a), morphological evidence described below and in previous studies (Pocock 1923; Moore and Tate 1965; Hayashida et al. 2006), and bioacoustic data (in C. caniceps sensu lato), we conclude that the populations of Callosciurus caniceps sensu lato inhabiting Sundaland, and Tamiops mcclellandii sensu lato populations to the east of the Himalayas and Arakan range, should be recognized as distinct species. We revalidate the specific status of Callosciurus concolor (Blyth, 1855) and Tamiops barbei (Blyth, 1847), as these names represent the earliest descriptions of these separately evolving lineages. Additionally, we provide emended diagnoses and detailed species comparisons for both taxa and their sister species.

Dorsal and ventral views of the skins of (A) Callosciurus caniceps (NHMUK 41.1817, lectotype); live images of (B) C. caniceps caniceps taken by Natthaphat Chotjuckdikul (Te’) in Bangkok, Thailand; (C) C. caniceps bimaculatus taken by Pattaraporn Vangtal in Railay Bay Beach, Krabi, Thailand; and (D) C. concolor taken by Cheong Weng Chun in Fraser’s Hill, Pahang, Malaysia.

Callosciurus caniceps (Gray, 1842)

Common name: Northern gray-bellied squirrel

กระรอกปลายหางดำเหนือ

Callosciurus concolor (Blyth, 1855)

Common name: Southern gray-bellied squirrel

กระรอกปลายหางดำใต้

Tamiops mcclellandii (Horsfield, 1839)

Common name. Himalayan striped squirrel

กระเล็นขนปลายหูสั้น

Tamiops barbei (Blyth, 1847)

Common name. Southeast Asian striped squirrel

กระเล็น

 Arlo Hinckley, Jesús E. Maldonado, Noriko Tamura, Jennifer A. Leonard and Melissa T. R. Hawkins. 2024. Lost in Synonymy: Integrative Species Delimitation reveals Two unrecognized Species of Southern Asian Tree Squirrels (Rodentia: Sciuridae: Callosciurinae). Vertebrate Zoology. 74: 683-707. DOI: doi.org/10.3897/vz.74.e133467