Sauromys petrophilus (Roberts, 1917)

Don E. Wilson & Russell A. Mittermeier, 2019, Molossidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 598-672 : 664

105.

Roberts’s Flat-headed Bat

Sauromys petrophilus

French: Tadaride de Roberts / German: Roberts-Flachkopf-Bulldogfledermaus / Spanish: Sauromis de Roberts

Other common names: Flat-headed Free-tailed Bat, Rock-dwelling Flat-headed Bat, Rock-loving Flat-headed Bat

Taxonomy. Platymops (Sauromys) petrophilus Roberts, 1917 ,

“Bleskop, near Rustenburg,” North West Province, South Africa . Although some authors, such as J. A. J. Meester and colleagues in 1986, have recognized up to five subspecies, these are not well defined geographically or morphologically and have not been recognized by recent authorities such as N. B. Simmons in 2005 or A. Monadjem and colleagues in 2010. The species is here considered monotypic, although the disjunct nature of the western and eastern populations, separated by 800 km, might lead to future genetic studies showing them to be distinct taxa. Monotypic.

Distribution. Two geographically disjunct ranges, including arid parts of extreme SW Angola, W Namibia, and W South Africa S to Western Cape Province, and N Mozambique, E & S Zimbabwe, extreme E Botswana, and N South Africa; an 800km-gap separates the two parts of the species’ range between Augrabies Falls on the Orange River in W South Africa and the Magaliesberg of North West and Gauteng provinces in N South Africa.

Descriptive notes. Head-body c¢.60-82 mm, tail 29-49 mm, ear 13-22 mm, hindfoot 6-10 mm, forearm 37-50 mm; weight 6-22 g. Males are slightly smaller than females. Roberts’s Flat-headed Bat is distinguished by extremely flattened head and body, as in Platymops . Fur is soft and dense, and variable in color above, from dark brown, medium yellowish brown or grayish brown to dark gray or pale gray; dark grayish brown to pale gray to whitish below. Wings are long, narrow and blackish brown to semi-translucent grayish-brown. Upper lip is smooth and with few coarse bristles (not spoon-hairs). Ears are quite large and simple, lacking fold, inner margins separated by narrow gap. Tragus is very small, and antitragus is indistinct. Interaural crest and gular gland are absent. Anterior palatal emargination is wide, and basisphenoid pits are shallow but large. As in Mormopterus and Platymops , lacrimal ridges form distinct tubercle on each side of rostrum. M® has two ridges of equal length. P? is relatively large, reaching cingulum of P*. Dentdl formulas 11/2, C 1/1, P 2/2. M 3/5 (x2) = 30. Chromosomal complement in Namibia and South Africa has 2n = 48 and FNa = 62.

Habitat. Dry woodland, mountain fynbos or arid scrub, associated with rocky areas. Elevational range up to 2000 m.

Food and Feeding. Roberts’s Flat-headed Bat is adapted for foraging in open spaces, and has long, narrow wings, with high wing loading (11-2 N/m?) and intermediate aspect ratio (7-2). Based on fecal pellets from 51 individuals collected in the Cederberg of Western Cape Province, South Africa, the diet comprised mostly Diptera (38% by volume), Hemiptera (33%), Coleoptera (20%), and Hymenoptera (8%), with much smaller proportions (under 1%) of Lepidoptera , Trichoptera , and Neuroptera .

Breeding. Pregnancy and lactations were recorded in the warm-wet season in mid-November in Zimbabwe, but not during the cool-dry season.

Activity patterns. Roberts’s Flat-headed Bats have a specialized flat head and body for roosting in narrow crevices under exfoliated layers, and in fissures in granite cliffs. Echolocation calls have low frequency (peak frequency ¢.30 kHz), narrow bandwidth (c.14 kHz), and medium-long duration (c.5 milliseconds).

Movements, Home range and Social organization. Roberts’s Flat-headed Bats roost communally in groups numbering usually up to four individuals.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. ACR (2017), Cotterill (2013h), Crawford-Cabral (1989), Jacobs & Fenton (2001, 2002), Meester et al. (1986), Monadjem, Jacobs, Cotterill, Hutson, Mickleburgh, Bergmans & Griffin (2017), Monadjem, Taylor et al. (2010), Peterson (1965a), Rautenbach (1982), Schoeman (2006), Schoeman & Jacobs (2003, 2008, 2011), Simmons (2005), Skinner & Chimimba (2005).

Figures

On following pages: 105. Roberts's Flat-headed Bat (Sauromys petrophilus); 106. Brazilian Free-tailed Bat (Tadarida brasiliensis); 107. European Free-tailed Bat (7adarida teniotis); 108. Egyptian Free-tailed Bat (7adarida aegyptiaca); 109. Kenyan Big-eared Free-tailed Bat (Tadarida lobata); 110. African Giant Free-tailed Bat (Tadarida ventralis); 111. Malagasy Free-tailed Bat (7adarida fulminans); 112. East Asian Free-tailed Bat (7adarida insignis); 113. La Touche's Free-tailed Bat (Tadarida latouchei); 114. New Guinea Free-tailed Bat (Austronomus kuboriensis); 115. White-striped Free-tailed Bat (Austronomus australis); 116. East Coast Free-tailed Bat (Micronomus norfolkensis); 117. Beccari's Free-tailed Bat (Ozimops beccaril); 118. Northern Coastal Free-tailed Bat (Ozimops cobourgianus); 119. Cape York Free-tailed Bat (Ozimops hall); 120. South-western Free-tailed Bat (Ozimops kitchener); 121. Loria’s Free-tailed Bat (Ozimops loriae); 122. Lumsden'’s Free-tailed Bat (Ozimops lumsdenae); 123. Inland Free-tailed Bat (Ozimops petersi); 124. Southern Free-tailed Bat (Ozimops planiceps); 125. Ride's Free-tailed Bat (Ozimops ride); 126. Hairy-nosed Free-tailed Bat (Setirostris eleryi).

Distribution. Two geographically disjunct ranges, including arid parts of extreme SW Angola , W Namibia , and W South Africa S to Western Cape Province, and N Mozambique , E & S Zimbabwe , extreme E Botswana , and N South Africa ; an 800km-gap separates the two parts of the species’ range between Augrabies Falls on the Orange River in W South Africa and the Magaliesberg of North West and Gauteng provinces in N South Africa .