Saturday, November 2, 2024

[Mammalogy • 2024] Typhlomys taxuansis • A New Species of the Genus Typhlomys (Rodentia: Platacanthomyidae) from Vietnam

 

Typhlomys taxuansis
Balakirev, Phuong & Rozhnov, 2024 

 
Abstract
Background: The paper presents novel findings of little-known species of rodents, the blind tree mice Typhlomys in Son La Province, Vietnam, with the first morphological and genetic characterisation and taxonomical description of the new species, T. taxuansis. The study also summarises all the data available on this genus species distribution, museum collections and notes on its taxonomy, which are important to establish the proper conservation status of the species. An exhaustive map of the findings is provided, along with a refined taxonomic key for all six currently morphologically characterised species of the genus. It is shown that, based on the data available to date, the genus is still far from complete. Most species, apparently, do not need a special conservation measure; their status may be established as Least Concerns and Near Threatened (B1a+2a) and the current population trend is stable (IUCN).

New information: The paper introduced innovative findings regarding lesser-known rodents, the blind tree mice Typhlomys in Son La Province, Vietnam, along with the primary morphological and genetic identification and taxonomic explanation of the novel species T. taxuansis.

Keywords: Southeast Asia, Vietnam, rodents, taxonomy, biodiversity

The holotype of Typhlomys taxuansis, skull, ZMMU S-210284 (field number: BY-60, adult female).
A Dorsal view; B Ventral view; C Lateral view; D Lower jaw, dorsal view; E Lower jaw, lateral view; H M1-M3 upper molars, occlusal pattern, enlarged scale; I m1-m3 lower molars, occlusal pattern, enlarged scale.

A new species of Typhlomys from Ta Xua Nature Reserve, specimen BY-60, adult female, external view.
A Dorsal view; B Ventral view; C Lateral view; D Belly, enlarged scale; E Head and backside, enlarged scale; F Distal half of tail with brush; G Hind foot, dorsal view.
Photo of Alexander E. Balakirev. 

Typhlomys taxuansis sp. nov.

Diagnosis: The new species, morphologically, is most similar to T. daloushanensis, but can be distinguished, based on its dental and skull morphology. Based on genetic diversity, the most relative genetic lineage is T. fengjiensis. It obviously differs from geographically most adjacent species T. chapensis and T. nanus by a more flattened braincase; from all known Typhlomys species, except for T. cinereus, by zygomatic arch with deeper incurve; from T. cinereus by mesofossette on M1 open on both buccal and lingual sides rather than open on the buccal side only; and from T. nanus by posterofossettid on M1 present. The new species further differs from other species, except T. daloushanensis, by anterofossette on M2 present.

Etymology: The specific Latin name taxuansis composed as an adjective refers to its type locality in Ta Xua Nature Reserve, Son La Province, Bac Yen District, Vietnam. Due to the sampling location being the southernmost location currently known for this genus, we suggest “southern blind tree mouse” as the English common name.


Alexander E. Balakirev, Bui Xuan Phuong, Viatcheslav V. Rozhnov. 2024. Typhlomys taxuansis (Rodentia, Platacanthomyidae): New Species of the Genus from northern Vietnam with Notes on conservation status and distribution. Biodiversity Data Journal. 12: e133363.  DOI: doi.org/10.3897/BDJ.12.e133363