Friday, February 21, 2020

[Mammalogy • 2020] Mirostrellus joffrei • A New Genus of Vespertilionid Bat: The End of A Long Journey for Joffre’s Pipistrelle (Chiroptera: Vespertilionidae)

Mirostrellus joffrei (Thomas, 1915)

in Görföl, Kruskop, Tu, Estók, Son & Csorba, 2020. 

Knowledge as to the taxonomic status of enigmatic bat species often is hindered by limited availability of specimens. This is particularly true for aerial-hawking bats that are difficult to catch. One such species, “Hypsugojoffrei, was originally described in Nyctalus due to its long and slender wings, but subsequently transferred to Pipistrellus, and most recently to Hypsugo, on the basis of morphology. Analysis of newly available material, which more than doubles the known specimens of this taxon, demonstrates that it is morphologically and genetically distinct from all other bat genera. We accordingly describe it as belonging to a new, monotypic genus. We provide a detailed description of its external and craniodental traits, measurements, and assessment of genetic relationships, including barcode sequences to facilitate its rapid identification in future. The new genus belongs to a group that includes the recently described Cassistrellus, as well as Tylonycteris, and its closest relative, Philetor. We also describe the echolocation calls emitted by members of the taxon in different situations, which may facilitate finding them in previously unsampled locations. Based on the new data, the species occurs from Nepal to North Vietnam and China, which suggests that it could be more widespread than previously thought.

Keywords: Indomalayan region, mtDNA, nuDNA, phylogeny, systematics, Vespertilionini

Habitus of a live adult female Mirostrellus joffrei from Mu Cang Chai, Vietnam (HNHM 26034). Note the coloration of the dorsal and ventral side, which is unique for this species.

Close up of the head of an adult male Mirostrellus joffrei from Mu Cang Chai, Vietnam (HNHM 26040).

Mirostrellus gen. nov.

Type species: Nyctalus joffrei Thomas, 1915.

Etymology: From the Latin “mirus” meaning “surprisemarvel,” which reflects that both the systematic position and the wide distribution of this bat (previously thought to be extremely rare) were pleasant surprises for the authors.

Diagnosis: A medium-sized vespertilionid, with a FA of 35.7–40.2 mm. The fifth finger of the wing is shortened (on average 20 mm shorter than the fourth finger) and the pelage is sparse and velvety. The supraorbital tubercles are well-developed, protruding for 1.47–1.76 mm measured from the lachrymal opening; the sagittal crest is barely visible, being only approximately 0.1 mm high. The upper canine is characterized by a developed posterior secondary cusp. The taxon has two upper and lower premolars and its lower molars are myotodont.

Lateral view of skull of Mirostrellus joffrei from Mu Cang Chai, Vietnam (HNHM 26041).

Dorsal, ventral, and lateral views of the skull and mandible of a male Mirostrellus joffrei from Tram Ton forest station, Vietnam (ZMMU S-186691). Scale bar =5 mm.

Lateral views of skulls of a) Mirostrellus joffrei (ZMMU S-186691); b) Philetor brachypterus (ROM 102019); c) Pipistrellus stenopterus (ZMMU S-103149); d) Hypsugo pulveratus (ZMMU S-167186); e) H. macrotis (MHNG 1486.94); f) H. alaschanicus (ZMMU S-108373); g) Tylonycteris malayana (ZMMU S-186637); h) Cassistrellus dimissus (MHNG 1926.053); i) Nyctalus leisleri (ZMMU S-176068). Scale bar =5 mm.

Penis of Mirostrellus joffrei from Mu Cang Chai, Vietnam (HNHM 26041). Not to scale.

Geographic distribution: The only known species of Mirostrellus gen. n. has an Indomalayan distribution, ranging from Nepal, NE India (Sikkim, Meghalaya), through the northern part of Myanmar, to North Vietnam (Saikia et al. 2017). In the National Museum of Prague (Czech Republic), four hitherto unreported specimens from western Yunnan, China (Zao Teng He, ..., 1,451 m a.s.l.), were revealed by SVK. The species probably also occurs between these localities as it is difficult to capture and so may be missed during faunal surveys (Fig. 10).

Tamás Görföl, Sergei V. Kruskop, Vuong Tan Tu, Péter Estók, Nguyen Truong Son and Gábor Csorba. 2020. A New Genus of Vespertilionid Bat: The End of A Long Journey for Joffre’s Pipistrelle (Chiroptera: Vespertilionidae). Journal of Mammalogy. gyz202. DOI: 10.1093/jmammal/gyz202