Bats of Southern and Central Africa. Ara Monadjem
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| TRAGUS | TAIL | CLAWS ON WING | OTHER |
|---|---|---|---|
| absent | small or absent, not contained in tail membrane | 1st + 2nd fingers | cheek-teeth without w-pattern of cusps |
| absent; well-developed anti-tragal lobe | moderate length tail enclosed within membrane | 1st finger | - |
| absent | moderate length tail enclosed within membrane | 1st finger | - |
| absent | moderate length tail enclosed within membrane | 1st finger | - |
| well-developed; divided | tail absent | 1st finger | 2nd finger has one phalanx, the 3rd has two phalanges |
| well-developed | moderate length tail enclosed within membrane ending in a T-shape | 1st finger | - |
| well-developed | tail protrudes from upper half of membrane near mid-point | 1st finger | pocket-like skin pouch between base of 5th finger and forearm (except Coleura afra and Saccolaimus peli) |
| absent or small; well-developed anti-tragus | terminal portion of tail protrudes beyond hind margin of tail membrane | 1st finger | - |
| well-developed | long tail fully enclosed within membrane | 1st finger | 2nd phalanx of 3rd digit not particularly lengthened |
| well-developed | long tail fully enclosed within membrane | 1st finger | conspicuous gland in each wing membrane; fur long, soft with yellow wash and without curled tips |
| well-developed | long tail fully enclosed within membrane | 1st finger | 2nd phalanx of 3rd digit three times longer than 1st phalanx |
Foraging ecology: Prey items, foraging behaviour and other relevant data (e.g. wing loading and aspect ratio) are included when available for southern Africa, or when data from elsewhere in Africa are likely to be true for southern Africa. Wing loading and aspect ratio are described as low if they are lower than 7, intermediate if they lie between 7 and 10.9, and high if they are greater than 10.9. Information on prey items and feeding behaviour is based on a number of studies of southern African species. These studies have generally described prey contents from the droppings of different species of bats, and related the findings to comparative observations of echolocation, wing morphology and feeding behaviour (e.g. Aldridge and Rautenbach 1987, Bowie et al. 1999, Jacobs 1999, Schoeman and Jacobs 2003, 2011, and numerous papers by M. B. Fenton). However, recent studies have applied molecular techniques to determine diet of southern African bats (Bohmann et al. 2011, Taylor et al. 2017, Weier et al. 2019a).
Reproduction: Gestation, litter size, birth season and any other relevant details are given when data are available for southern Africa, or when available only for other parts of Africa and likely to be true for the subregion.
Systematic notes: Recent taxonomic studies and points of taxonomic debate are discussed at the end of each species account.
Measurements: Means, standard deviations and ranges of each species are given for males and females separately (but have been combined where small sample sizes do not allow for this), for mass (in grams) and for the following linear measurements (in millimetres): forearm length, total body length, tail length, tibia length and condylo-incisive skull length. Other measurements are occasionally presented for certain species (e.g. greatest skull length) where these measurements are important in identifying the species. To reduce variability, most of the measurements presented in this book were taken by two authors (P. J. Taylor and A. Monadjem). As far as possible, only measurements of adults have been used: FA = forearm length; Total = total length (including tail); Tail = length of tail; Tibia = length of tibia; Ear = length of ear; CI = condylo-incisive length; GSL = greatest skull length.
SUBORDER PTEROPODIFORMES
Family Pteropodidae
Fruit bats
The Pteropodidae encompass a diverse assemblage of fruit-eating bats, represented by over 30 species in mainland Africa (Happold and Happold 2013, Nesi et al. 2013, Hassanin et al. 2015), of which 21 species in 11 genera occur in southern Africa. The only mainland genera not recorded in southern Africa are Nanonycteris and Scotonycteris, which are restricted within the rainforest zone. Nevertheless, museum records of Scotonycteris bergmansi Matschie 1894 mapped by Bergmans (1990) extend nearly to 4°S in the Congo basin. So, it is likely that S. bergmansi occurs in our area, if not resident, then possibly as a migrant.
Furthermore, several species of Pteropus breed on islands in the Indian Ocean, some very close to the mainland (at Pemba and Zanzibar).
The Pteropodidae are a distinctive group, readily distinguished from other bats by the possession of two claws on the wing (all other bats have only one wing claw, which is the homologue of our thumb) (Figure 43b). Traditionally, they are also viewed as being larger than ‘microbats’, but this is not always so. For example, at 13 g, the diminutive pteropodid Megaloglossus woermanni is smaller than many ‘micro-bat’ species. However, it is true that the largest bats belong to this family. In Africa, Hypsignathus and Eidolon may have forearm lengths of over 120 mm, and a large male of the former can exceed 400 g. By comparison, the largest ‘microbats’ weigh less than 200 g. The other typical features of the Pteropodidae are their dog-like faces with elongated muzzles and large eyes (Figure 43a), and their diet of fruit. In contrast to the ‘microbats’, eyesight is important in the Pteropodidae – they rely on this sensory organ for perception of their environment. A distinctive form of echolocation has developed in only one genus, Rousettus (Neuweiler 1990).
Figure 43. A typical Pteropodidae species: (a) head showing the large eyes and absence of noseleafs, and (b) wing showing the presence of claws on the first and second digits.