Rhinolophus denti, Thomas, 1904

Burgin, Connor, 2019, Rhinolophidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 280-332 : 286-287

13 . Dent’s Horseshoe Bat

Rhinolophus denti

French: Rhinolophe de Dent / German: Dent-Hufeisennase / Spanish: Herradura de Dent

Taxonomy. Rhinolophus denti Thomas, 1904 ,

“ Kuruman , Bechuanaland [Northern Cape Province, South Africa]. Alt. 1300 m. ”

Rhinolophus denti is in the capensis species group and seems to be sister to a clade including A gorongosae , R rhodesiae , R simulator, and a Liberian specimen of R landeri according to a recent phylogenetic study. Specimens from Zambia and Mozambique have been misidentified as R denti but are now known to represent R rhodesiae , and a specimen from The Gambia previously attributed to R denti has been shown to represent R landeri . Two subspecies recognized.

Subspecies and Distribution. R d. denti Thomas, 1904 - SW Angola, N Namibia, NW & SW Botswana, and N South Africa (Northern Cape Province). There is an unconfirmed record from SW Republic of the Congo.

R d. knorri Eisentraut, 1960 - scattered records across W Africa in SE Senegal, Guinea-Bissau, W Guinea, N Sierra Leone, N Ivory Coast (but possibly representing Lander’s Horseshoe Bat, R landeri ), NE Ghana, S Burkina Faso, and Nigeria. There is apparently a specimen from S South Sudan that might represent this subspecies, although its identity needs to be validated.

Descriptive notes. Head-body c. 44-60 mm, tail 17-24 mm, ear 14—21 mm, hindfoot 9 10 mm, forearm 37-44 mm; weight 4—9 g. Pelage is pale brown or buff to pale gray or cream dorsally (hairs are almost unicolored or very pale, with brown/gray tips) and white, off-white, or pale gray ventrally; orange morph is bright orange dorsally and slightly paler ventrally. Color is usually darker in subspecies knorri. Males lack axillary tufts. Ears are comparatively short (38-48% of forearm length). Noseleaf has subtriangular and relatively short lancet that is covered in fine hairs, being slightly concave on sides, with bluntly pointed tip; connecting process is rounded and about the height of sella tip; sella is naked, with almost parallel to slightly concave sides and broad and rounded top; lobes at base of sella are comparatively low; horseshoe is narrow at 6-8— 7- 5 mm, nearly covers muzzle, and has no lateral leaflets; and anterior emargination is a distinct notch. Lower lip has three grooves. Wings and uropatagium are grayish black or brown. Skull is delicately built, with thin zygomatic arches, and zygomatic width is equal to or slightly larger than mastoid width; nasal swellings are rounded; frontal depression is shallow and supraorbital ridges are weakly developed; and sagittal crest is poorly developed anteriorly and absent posteriorly. P 2 is small but in tooth row, well separating C1 and P4; C1 is conspicuously shorter and smaller than C1; and P3 is minute and fully displaced labially, allowing contact between P2 and P4. Chromosomal complement has 2n = 58 and FNa = 62 ( South Africa).

Habitat. Variable woodland habitats, including undifferentiated and Isoberlinia (Fabaceae) woodlands, and rainforest-savanna mosaic habitats in West Africa, and desert and semiarid habitats such as Bushy Karoo-Namib shrubland, Kalahari Acacia (Fabaceae) wooded grasslands, and areas of the Namib Desert in southern Africa. Presence of roosts seems to be an indicator of which habitats Dent’s Horseshoe Bats are found in. Roosts in southern Africa are found primarily in deep parts of caves, where colonies have been found hanging from stalactites (Drotsky’s Caves, Botswana) and in complete darkness. Roosts have also been found in thatched roofs and culverts under roads. In Western Africa, roosts have been reported in caves, under a bridge, and in a hollow Kapok tree ( Ceiba pentandra , Malvaceae ).

Food and Feeding. Dent’s Horseshoe Bats are insectivorous.

Breeding. No information.

Activity patterns. Dent’s Horseshoe Bats are nocturnal. At low temperatures (mean of 24 - 4°C), they enter daily torpor in Namibia, sheltering in humid cave microclimates. Call shape is FM /CF/ FM, with mean F component of 110-9 kHz in South Africa recorded by D. S. Jacobs and colleagues in 2007; all previous echolocation data attributed to Dent’s Horseshoe Bats actually were from Roberts’s Horseshoe Bat ( rhodesiaé ).

Movements, Home range and Social organization. Dent’s Horseshoe Bats roost alone or in groups of two to dozens of individuals. They hang in open clusters in which a few individuals hang near one another but do not touch. One individual was found roosting with a group of Nycteris .

Status and Conservation. Classified as Least Concern on The IUCN ed List. Dent’s Horseshoe Bat has a wide but fragmented distribution and is not well documented. Although no major threats have been identified, it might be threatened by roost disturbance and overall habitat destruction.

Bibliography. ACR (2018), Bates eta/. (2013), Churchill eta/. (1997), Cotterill (2013a), Csorba eta/. (2003), Decher et al. (2010), Herkt et al. (2017), Jacobs et al. (2007), Monadjem, Griffin et al. (2017a), Rautenbach (1986), Stoffberg étal. (2010),Taylor, Macdonald eta/. (2018).

Figures

On following pages: 4. Lander's Horseshoe Bat (Rhinolophus landeri); 5. Guinean Horseshoe Bat (Rhinolophus guineensis); 6. Blasius's Horseshoe Bat (Rhinolophus blasii); 7. Peters's Horseshoe Bat (Rhinolophus lobatus); 8. Swinny's Horseshoe Bat (Rhinolophus swinnyi); 9. Cape Horseshoe Bat (Rhinolophus capensis); 10. Gorongosa Horseshoe Bat (Rhinolophus gorongosae); 11. Roberts's Horseshoe Bat (Rhinolophus rhodesiae); 12. Bushveld Horseshoe Bat (Rhinolophus simulato/); 13. Dent's Horseshoe Bat (Rhinolophus denti); 14. Cameroon Horseshoe Bat (Rhinolophus alticolus); 15. Mehely's Horseshoe Bat (Rhinolophus mehelyi); 16. Mediterranean Horseshoe Bat (Rhinolophus euryale); 17. Hildebrandt's Horseshoe Bat (Rhinolophus hildebrandtii); 18. Mount Mabu Horseshoe Bat (Rhinolophus mabuensis); 19. Cohen's Horseshoe Bat (Rhinolophus cohenae); 20. Smithers's Horseshoe Bat (Rhinolophus smithersi); 21. Mozambican Horseshoe Bat (Rhinolophus mossambicus); 22. Rüppell's Horseshoe Bat (Rhinolophus fumigatus); 23. Eloquent Horseshoe Bat (Rhinolophus Bloquons).

Subspecies and Distribution. R d. denti Thomas, 1904 - SW Angola , N Namibia , NW & SW Botswana , and N South Africa (Northern Cape Province). There is an unconfirmed record from SW Republic of the Congo . R d. knorri Eisentraut, 1960 - scattered records across W Africa in SE Senegal , Guinea-Bissau, W Guinea , N Sierra Leone , N Ivory Coast (but possibly representing Lander’s Horseshoe Bat, R landeri ), NE Ghana , S Burkina Faso , and Nigeria . There is apparently a specimen from S South Sudan that might represent this subspecies, although its identity needs to be validated.