Читать книгу Bats of Southern and Central Africa - Ara Monadjem - Страница 51

SPECIES ACCOUNTS

Оглавление

This section contains species accounts for 125 species of bats known to occur in the southern African region, accompanied by identification matrices, distribution maps, spectrograms (also called sonograms), photographs of bats and their skulls, and tables of measurements.

Rather than using dichotomous keys, which can be misleading, especially when characters are missing, we provide identification matrices throughout, providing important characters for all species. Table 4 presents an identification matrix for distinguishing between the 11 families of bats found in southern Africa.

The families are arranged phylogenetically within the two orders Pteropodiformes and Vespertilioniformes. Each family account starts with a general description of the family and genera, followed by one or more identification matrices to the genera and species. Within each identification matrix, taxa are arranged according to ascending size (FA length). Species accounts are arranged alphabetically within each family. Each species account covers the following aspects.

Name: Scientific and common names are given (following Simmons 2005, except as stated), together with the author and date of description of each genus and species.

Conservation status: Global Red List categories appear after the name in each account. These are sourced from the 2017 IUCN Red List of Threatened Species (www.iucnredlist.org); the original ratings were based on mutual consensus among bat biologists at the January 2004 Global Mammal Assessment meeting in London.

Description: External, cranial and dental characters are described. Where known, the dental formula of each species is presented as follows: 2132/2133 = 34, where the numbers before the slash refer to the teeth in half of the upper jaw and the ones after it to half the teeth in the lower jaw. In this example, the species has four upper incisors, two canines, six premolars and four molars in the upper jaw – a total of 34 teeth. Figure 40 illustrates the dental and osteological features referred to in this book.





Figure 40. (a) Dorsal, (b) ventral, and (c) lateral views of the skull, and (d) lateral view of the mandible of a typical bat showing the osteological features that are referred to in this book. Grid squares represent 2 mm × 2 mm in all skull and mandible photographs, except where a note in the caption states otherwise.

Key identification features: Diagnostic species characteristics useful for identification are provided, as well as comparisons between closely related species that may be easily confused. These features are also summarised in the relevant identification matrices provided for each family and genus. In some cases, diagnostic traits are visible from the species photographs and skull photographs (dorsal, ventral and lateral views of the cranium and lateral view of the mandible).

Echolocation call: We provide spectrograms and call parameters of time-expanded or full spectrum (.WAV) calls for at least 60 species for which we have data, because these have been shown to be superior to those obtained with zero-crossing using the ANABAT system (Fenton et al. 2001). Nevertheless, given the large user base of bat workers using the ANABAT system, we provide relevant species call parameters for 29 species in Table 3. For more information, see Echolocation.

Distribution, habitat and roosting: We plotted the provenance of all known museum specimens as locality records. We also included photographic distribution records for a small number of easily identifiable species, for example, Taphozous mauritianus and Eidolon helvum. Where possible, we have given the museum accession number for the type specimen of each species, and have stated in which museum the specimen is deposited.

The distribution maps in the first edition included the predicted potential distribution of each species in southern Africa based on MaxEnt models (Elith et al. 2006). Because these models obscured the actual distribution points, and some political boundaries, we have removed them in this edition.


Figure 41. Anatomy of a typical bat.


Figure 42. Measurements used in bat identification: Fa forearm length; Tib tibia length; Ear length of ear from notch to tip; Trag length of tragus in the ear; 3 met length of metacarpal in the third finger of the wing; 5 met length of metacarpal in the fifth finger of the wing; Tail tail length from tip to anus; HB head and body length from nose tip to anus; Foot hindfoot length, heel to toe tips, excluding claws; P1 length of first phalanx of the third finger of the wing; P2 length of second phalanx of the third finger of the wing; P3 length of third phalanx of the third finger of the wing.

TABLE 4.

TABLE 4. IDENTIFICATION MATRIX FOR SOUTHERN AFRICAN CHIROPTERAN FAMILIES

FAMILY FACE EYES NOSELEAF EARS
Pteropodidae dog-like large absent simple, edge forming an unbroken ring
Rhinolophidae not dog-like tiny complex – pointed tip large – triangular
Hipposideridae not dog-like tiny complex – half-moon shape; sella and connecting process absent large – triangular
Rhinonycteridae not dog-like tiny complex – tridentate (three-pronged) large – triangular
Megadermatidae not dog-like large enveloped by pointed spike very long, rabbit-like
Nycteridae not dog-like tiny vertical slit in face, covering noseleaf beneath very long, rabbit-like
Emballonuridae not dog-like large absent intermediate length
Molossidae not dog-like small absent intermediate to large, co-joined
Vespertilionidae not dog-like small absent simple, usually separate
Cistugidae not dog-like small absent simple, separate
Miniopteridae not dog-like small absent simple, separate
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.

Bats of Southern and Central Africa

Подняться наверх