Mormopterus acetabulosus

6.

Mauritian Little Mastiff Bat

Mormopterus acetabulosus

French: Molosse de Port-Louis / German: Mauritius-Mastino-Fledermaus / Spanish: Mormoptero de Port-Louis

Other common names: Mauritian Free-tailed Bat, Natal Free-tailed Bat

Taxonomy. Vespertilio acetabulosus Hermann, 1804,

Port Louis, Mauritius.

Because the holotype could not be located in the Muséum national dhistoire naturelle in Paris, S. M. Goodman and colleagues in 2008 designated Field Museum of Natural History (FMNH) 1984-368, from Palma Cave, Palma, Black River District, Mauritius, 20° 16 -405’ S, 57° 27 -147’ E,as the neotype of M. acetabulosus. A. S. Cheke in 2009 reported on drawings of the type specimen that were referred to in the original description, suggesting that the designation of a neotype was unnecessary. Nevertheless, because a physical specimen is necessary for formal revision according to the International Code for Zoological Nomenclature, validity of the neotype is here affirmed. M. francoismoutoui from Réunion Island was until 2008 considered part of M. acetabulosus, but the two species differ genetically and based on several morphological characteristics, including larger size of M. acetabulosus and its more widely spaced ears compared with M. francoismoutour, in which the ears are closer together and joined by flap of skin that is absent in M. acetabulosus. Although the subspecies name M. acetabulosus natalensis by A. Smith in 1847 is available for the two specimens recorded from Durban in South Africa, the fact that these individuals were vagrants and that there is no viable population in South Africa makes recognition of subspecies redundant. Monotypic.

Distribution. Restricted to Mauritius; there are two isolated records attributed to this species from the Durban region on E coast of South Africa. Previous authors considered it to occur on Madagascar, but Goodman and coworkers found no evidence for its occurrence there.

Descriptive notes. Head-body 49-52 mm, tail 43-50 mm, ear 15-18 mm, hindfoot 6-7 mm, forearm 38-43 mm; weight 6-8-2 g. The Mauritian Little Mastiff Bat has slightly flattened head, no facial ornamentation, and tail protruding beyond hind margin of uropatagium. Dorsal fur is short, uniformly dark brown, and unicolored above; fur becomes paler on abdomen. Wings and uropatagium are dark brown. Ears are small, erect, subtriangular, without complex folds, and separated at bases, with distinct sickle-shaped emargination below tips. Tragus is small but not concealed by antitragus. Adult males have distinct throat gland that is absent in females. Upperlips have several deep wrinkles, few spoon-hairs, and many fine hairs. Hindclaws have fine hairs and many stout bristles. Braincase is slightly flattened, palatal emargination is wide, and basisphenoid pits are poorly developed. Third ridge of M? is longer than second. Dental formulaisl 1/3, Cl1/1,P1/2 M3/3 (x2) = 30.

Habitat. Scrubland, woodland, and agricultural areas.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. Mauritian Little Mastiff Bats are nocturnal and roost in lava tunnels at apparently less than five sites on Mauritius.

Movements, Home range and Social organization. Colonies of Mauritian Little Mastiff Bats have up to tens of thousands of individuals.

Status and Conservation. Classified as Endangered on The IUCN Red List. The few roosting sites of Mauritian Little Mastiff Bats are threatened by human disturbance. Populations have declined 80% in the past 18 years. Based on visits to five cave sites between 2005 and 2012 when no obvious declines were observed,it is possible that notall sites are declining as substantially as indicated on The IUCN Red List, and there might be additional unsurveyed cave sites that are not yet impacted. Nevertheless, the fact that this species does not seem to have adapted to roosting in human structuresis cause for concern.

Bibliography. Bergmans, Hutson, Oleksy & Taylor et al. (2017), Cheke (2009), Goodman, Jansen van Vuuren et al. (2008), Smith (1847).