Saturday, February 3, 2018

[Mammalogy • 2018] Tylonycteris malayana eremtaga • A New Subspecies of the Malayan Bamboo Bat (Chiroptera: Vespertilionidae) from the Andaman Islands, India

Tylonycteris malayana eremtaga
Srinivasulu, Srinivasulu, Srinivasulu & Jones, 2018

 The bamboo bats belonging to the genus Tylonycteris are unique due to their morphology and ecology, and are known from few locations in South Asia. We collected voucher specimens of Tylonycteris malayana from North Andaman Island, which forms the basis of the first specimen-based record of this species from the Andaman & Nicobar Islands, and the second record from India. Our analyses based on morphometrics, craniodental measurements, bacular morphology and molecular phylogeny based on cytochrome c oxidase subunit I gene indicate that the insular population of T. malayana may have diversified in isolation to differ from the mainland forms, and could represent putative new subspecies, described herein. In light of the new findings, we discuss the importance of conducting detailed study on the specimens of the Lesser Bamboo Bat earlier reported from the Andaman & Nicobar Islands to ascertain their taxonomic status.

Keywords: Bamboo Bat, cryptic diversity, molecular phylogeny, North Andaman Island, Tylonycteris pachypus.

Tylonycteris malayana eremtaga ssp. nov.
Andaman Bamboo Bat

Holotype: NHMOU.CHI.151.2015, adult male, 06.xi.2015, near Bamboo Tekri, Chipo Village, Diglipur, North Andaman Island, Andaman & Nicobar Islands, India; coll. A. Gopi & Tauseef Hamid Dar.

Diagnosis: A small bat with a forearm length up to 23.3–26.25 mm. Dorsal pelage uniformly grey-brown, venter slightly paler; wings and interfemoral membrane dark brown. Although the new subspecies is essentially similar to nominotypic T. m. malayana (see Tu et al. 2017), it varies from the nominate form slightly in having smaller craniodental features (GTL: 11.5 in T. m. eremtaga ssp. nov. vs 11.73–12.90 in T. m. malayana). The rostrum is robust in T. m. eremtaga ssp. nov., shorter and broader than that of the nominate subspecies (CM3: 3.7–4.1 in T. m. eremtaga ssp. nov. vs 3.74–4.31 in T. m. malayana; RW: 5.7–6.1 in T. m. eremtaga ssp. nov. vs 5.3–5.6 in T. robustula sensu lato (see Bates & Harrison 1997). Externally, the fur color of T. m. eremtaga ssp. nov. appears to be uniform grey-brown while that of T. m. malayana is dark brown.

Description: A small bat with a forearm length up to 26.25mm. Head characteristically flat, projecting forwards and downwards (Image 1a). Ears roughly triangular with broadly rounded tips. Tragus short and broad. Base of the thumb and the soles of the feet have broad fleshy pads (Image 1b). Wings short with 3rd, 4th and 5th metacarpals roughly equal in length. Wing and interfemoral membranes dark brown (Image 1a,b), pelage fine and dense, uniformly grey-brown on the dorsum, slightly paler on the ventral surface. ....

Etymology: The subspecific epithet, ‘eremtaga,’ is a Latinized noun derived from the Aka-Kora dialect of the Great Andamanese language, meaning ‘forest-dweller’.

Ecological notes: The presence of multiple males in the area suggests the existence of a colony of these bats in the near vicinity of the village. The specimens collected from Chipo Village, Diglipur, North Andaman Island were found to share their habitat with other species such as the Greater Short-nosed Fruit Bat Cynopterus sphinx, the Lesser Short-nosed Fruit Bat Cynopterus brachyotis, Tickell’s Bat Hesperoptenus tickellii, and the Andaman Intermediate Horseshoe Bat Rhinolophus affinis andamanensis. This subspecies is currently known only from Chipo Village, Diglipur, North Andaman Island, Andaman & Nicobar Islands, India.

Chelmala Srinivasulu, Aditya Srinivasulu, Bhargavi Srinivasulu and Gareth Jones. 2018. A New Subspecies of the Malayan Bamboo Bat (Chiroptera: Vespertilionidae: Tylonycteris malayana eremtaga) from the Andaman Islands, India.  Journal of Threatened Taxa. 10(1); 11210–11217.   DOI: 10.11609/jott.3906.10.1.11210-11217

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