Rhinopoma muscatellum, Thomas, 1903

Don E. Wilson & Russell A. Mittermeier, 2019, Rhinopomatidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 164-176 : 174

2.

Muscat Mouse-tailed Bat

Rhinopoma muscatellum

French: Rhinopome de Muscat / German: Muscat-Mausschwanzfledermaus / Spanish: Rhinopoma de Mascate

Other common names: Small Mouse-tailed Bat

Taxonomy. Rhinopoma muscatellum Thomas, 1903 ,

“Wadi Bani Ruha,” Muscat, Arabia ( Oman).

Rhinopoma muscatellum was considered a subspecies of R. hardwickii until A. F. De-Blase and colleagues in 1973 convincingly demonstrated differences between them, supporting their status as distinct species. With regard to larger size of individuals from eastern Iran and Afghanistan, they proposed separate subspecific status of seicanum. Molecular analyses revealed that divergence between muscatellum and hardwickii was even deeper than expected: muscatellum and hadramauticum form a common clade with microphyllum and quite distant from the clade of other forms of Rhinopoma . Large genetic distance between samples of R. muscatellum from Oman and those from Iran (4-9-5-4% based on cytochrome-b), together with data on phenotype homogeneity of all Iranian samples including topotypic seianum, suggest a split of R. muscatellum into two distinct clades. Correspondingly, two subspecies recognized.

Subspecies and Distribution.

R.m.muscatellumThomas,1903—EArabianPeninsulaatAl-HajarMts(EUnitedArabEmiratesandNEOman).

R. m. secanum Thomas, 1913 — W & S Iran, S Afghanistan, and S Pakistan, up to 34° N; perhapsalso India, but records from Genji in Rajasthan and Gingee in Tamil Nadu are doubtful (suspected misidentification).

Descriptive notes. Head—body 53-64 mm, tail 56-75 mm, ear 18-3-22-4 mm, hindfoot 12-13 mm, forearm 48-5-55-4 mm; weight 4-6-14 g. The Muscat Mouse-tailed Bat is a small form of Rhinopoma (greatest lengths of skull 15-5-17-5 mm and lengths of tooth row from C' to M? 5-3-6-1 mm), with tail longer than forearm. Pelage is unicolored, pale gray without brownish tint typical for other species of Rhinopoma and lighter on belly. Shape of nasal plate of the Muscat Mouse-tailed Bat differs from the Lesser Mouse-tailed Bat ( R. hardwickii ) and the Arabian Mouse-tailed Bat ( R. cystops ), particularly by lack of inflationsof lateral ridges and flat dorsal ridge sometimes having slight medial depression instead of triangular noseleaf structural characteristic of the latter species. Anterior part of skull of the Muscat Mouse-tailed Bat is narrower than in the Arabian Mouse-tailed Bat and more parallelsided, so that the outline as seen from above runs backward and then abruptly turns outward at zygomatic bone; in the Arabian Mouse-tailed Bat and other species of Rhinopoma , general outline diverges evenly to the broadest point of zygomatic bone. Nasal prominences are large, thin, and inflated and project forward in front of anterior end of middle line of nasals. Hind edge of palate is distinctly behind level oflast molar. Bullae are conspicuously larger than in congeners. Nasal inflations are conspicuously large in lateral view, with angular anterior expansion attaining plain anterior to mesial base of canine. In adult Muscat Mouse-tailed Bats, lateral and distal margins of nasal inflations tend to form bony crest of pentagonal shape,typically accompanied by deep slit-like medial groove in posterior part of internasal surface. Palatal incision is distinctly V-shaped and terminates posterior to plane of last molars. Least breadths of post-palatal projection of the Muscat Mouse-tailed Bat are 1-6-2-2 mm compared to 2:2-2-7 mm in the Lesser Mouse-tailed Bat. Sagittal crest is moderately high in frontal region and indistinct in parietal part. Further differences from other species of Rhinopoma , partly shared with the Greater Mouse-tailed Bat ( R. microphyllum ), are dental characteristics: C' has distinct distal cingular cusp; upper molariform teeth are delicately build; talons are much narrower than in other species; and their palatal wall is low, with no talonal cusp on P* but a separate, mesially tapered, cingular protuberance at buccal crown axis. Talons of molars, particularly M', are quite narrow and tapered distally, with low palatal margin and shallow hypoconal undulation without cusp-like termination (as appears in R. hardwickii group). Distinct rudimentary metacrista of M? is turned distally. Mesial cingular ridge on palatal side of C,is present, P,is relatively small, and P, is elongated, typically with broad distal basin.

Habitat. Arid semi-desert habitats from sea level to elevations of 1190 m (750 m on average). The Muscat Mouse-tailed Bat roosts in small caverns and rocky niches, narrow crevices in rocky cliffs, and dark areas in spacious karst caves, often in mixed colonies with the Greater Mouse-tailed Bat. Foraging areas of the Muscat Mouse-tailed Bat are treeless arid landscapes, often along rivers.

Food and Feeding. The Muscat Mouse-tailed Bat regularly eats small-sized beetles and definitely prefers winged ants in autumn. Ants (Formicoidea) dominated seven of nine diet samples from Oman, and beetles dominated two. Ants also dominated (up to 95%) three of seven diet samples in Iran (all from October and early November); a late November sample had diverse prey, with predominant representation of Heteroptera (62%) not recorded in other samples; two April samples had high proportions of beetles (mostly smaller Scarabaeidae and Carabidae ) and increased representation of Lepidoptera (10%) not recorded in autumn diets.

Breeding. In Oman, pregnant Muscat Mouse-tailed Bats were recorded in June-July, and lactating females were recorded in August and early September.

Activity patterns. Spring and autumn records suggest foraging activity in that time. Whether it continues in winter period is not clear. Field records of echolocation calls revealed frequency ranges of second harmonic: 30-37 kHz in Iran and 31-33 kHz in Oman.

Movements, Home range and Social organization. Most data about the Muscat Mousetailed Bat are anecdotal and mostly from autumn (October-November) and spring (April-May). A few reports on female maternity colonies suggest sexual segregation in summer, while in autumn, winter, and spring samples, both sexes appear together in equal proportions. In many cases, one orjust few individuals were found in a daytime roost, typically hidden in rocky crevices. Size of colonies occupying walls of caverns or spacious caves varies from few to 50 individuals. Muscat Mouse-tailed Bats often share roost with Greater Mouse-tailed Bats, Egyptian Rousettes ( Rousettus aegyptiacus), Geoftroy’s Trident Leaf-nosed Bats (Asellia tridens), and Egyptian Tomb Bats ( Taphozous perforatus). An aggregation of 200 Muscat Mouse-tailed Bats found in Sistan (Iranian Balochistan) in late November indicated a tendency to form large winter colonies. Frequent appearance ofsingle bats or small groups in close vicinity to a larger colony roost suggests a fission—fusion pattern of roost occupancy at least in spring and autumn.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Although the Muscat Mouse-tailed Bat is rarely recorded,it has a relatively wide distribution, occurs in a broad variety of habitats, and is unlikely to be declining fast enough to qualify for listing in a more threatened category. It is considered near threatened in Pakistan.

Bibliography. Akmali et al. (2017), Bates & Harrison (1997), Benda & Gaisler (2015), Benda etal. (2012), DeBlase (1980), DeBlase et al. (1973), Dookia & Singh (2017), Ghalib et al. (2007), Harrison & Bates (1991), Hill (1977), Hulva, Horacek & Benda (2007), Judas et al. (2018), Kock (1969d), Largen et al. (1974), Lay (1967), Molur et al. (2002), Qumsiyeh & Jones (1986), Shahabiet al. (2017), Thomas (1903b, 1913a), Van Cakenberghe & De Vree (1994).

Figures

1. Greater Mouse-tailed Bat (Rhinopoma microphyllum), 2. Muscat Mouse-tailed Bat (Rhinopoma muscatellum), 3. Hadramaut Mouse-tailed Bat (Rhinopoma hadramauticum), 4. Lesser Mouse-tailed Bat (Rhinopoma hardwicku), 5. Arabian Mouse-tailed Bat (Rhinopoma cystops)

Subspecies and Distribution. R.m.muscatellumThomas,1903—EArabianPeninsulaatAl-HajarMts(EUnitedArabEmiratesandNEOman). R. m. secanum Thomas, 1913 — W & S Iran , S Afghanistan , and S Pakistan , up to 34° N; perhapsalso India , but records from Genji in Rajasthan and Gingee in Tamil Nadu are doubtful (suspected misidentification).