Notes on the dry season roosting and foraging behaviour of Epomophorus gambianus and Rousettus aegyptiacus (Chiroptera :Pteropodidae)

We studied the movements and foraging behaviour of Epomophorus gambianus and Rousettus aegyptiacus during the dry season in Rhodesia. The nightly activity of both species was concentrated in the riparian forest where they fed on the fruits of Diospyros senensis. Epomophorus gambianus roosted during the day high in the thick canopy of Trichelia emetica or Kigelia africana along the river banks and began foraging, each one in a preferred D. senensis shrub, before 1845 hrs. Rousettus aegyptiacus arrived in the study area approximately one hour later and appeared to forage in groups. The temporal separation of the feeding times of the two species of bats may provide a basis for the partitioning of a single species food resource.     

A reassessment of the taxonomic status and phyletic relationships of Papio baringensis and Papio quadratirostris (Primates: Cercopithecidae)

Comparison of the skulls of Papio baringensis Leakey 1969 from the Chemeron Formation and P. quadratirostris Iwamoto 1982 from the Usno Formation with those of Theropithecus gelada, T. brumpti, T. darti, T. oswaldi, and several species of Papio indicate that the species from Chemeron and Usno exhibit all, or most, respectively, of the shared derived characters of Theropithecus. We propose that they be removed from Papio and placed in Theropithecus as T. baringensis and T. quadratirostris. Comparison of the specimens of T. baringensis and T. quadratirostris with those of T. brumpti indicate that the former two species have some of the derived characters of T. brumpti but are primitive in others. We propose that the three species form the following phyletic lineage: T. baringensis-T. quadratirostris-T. brumpti. With these referrals, there are now six species of the genus Theropithecus. Based on geologic grounds, the specimens from Chemeron are about 4.0 million years (m.y.), that from Usno between 3.3 and 3.4 m.y., and those of T. brumpti between 2.0 and 2.8 m.y. in age. We also show that the most complete specimen of Papio sp. nov. from Olduval Gorge belongs to T. oswaldi. With the removal of these specimens from Papio, the East African fossil record of this genus, apart from isolated teeth, comprises only 21 specimens, while that of Theropithecus comprises at least 300 specimens.     

Phylogenetic relations between microbats, megabats and primates (Mammalia: Chiroptera and Primates)

We examine the paraphylectic hypothesis of bat origins, both in the light of previous discussions, and in the light of new evidence from our analyses of neurological traits and wing morphology. Megabats share with primates a variety of complex details in the organization of neural pathways that have not been found in any other mammalian group, particularly not in microbats. The features previously used to link microbats and megabats have been examined and found to be questionable bases for support of a monophyletic origin. In particular, morphological analyses of the musculoskeletal adaptations associated with the flight apparatus are consistent with two separate origins of the mammalian wing. Taken together, these analyses suggest that megabats evolved from an early branch of the primate lineage. This branch was comprised of moderate-sized, phytophagous gliders, of which the other living descendants are the dermopterans. Microbats, in contrast, probably evolved much earlier from small, agile insectivores whose forelimbs had long metacarpals in relation to their phalanges.     

Seasonal variation in growth of Mastomys natalensis (Rodentia: Muridae) in Morogoro, Tanzania

The paper describes seasonal growth variation in a free living population of Mastomys natalensis (Smith, 1834) from Morogoro, Tanzania. Growth patterns are associated with rainfall patterns. Young animals enter a growth stop at the end of the dry season (October-November) and growth is only resumed after the first heavy rains. Reproduction is more related to size than to age. If the heavy rains come early in the rainy season, animals start reproducing in the beginning of the year. The resulting young reach their maximal size without growth stop and start reproducing immediately. Possible causes for the growth stop are discussed. Growth phenomena are thought to explain at least partially the relation between rainfall and reproduction in Mastomys .

Résumé

Cet article décrit la variation de croissance saisonnière d'une population de Mastomys natalensis (Smith, 1834) vivant en libertéà Morogoro, en Tanzanie. Les graphiques de croissance sont associés à ceux des chutes de pluie. Les jeunes animaux connaissent un arrêt de la croissance à la fin de la saison sèche (octobre-novembre) et la croissance ne reprend qu'après les premières fortes pluies. La reproduction est plus liée à la taille qu'à l'âge. Si les fortes pluies surviennent tôt en saison des pluies, les animaux commencent à se reproduire au début de l'année. Les jeunes atteignent alors leur taille maximale sans avoir connu d'arrêt de croissance et commencent à se reproduire immédiatement. On pense que les phénomènes de croissance expliquent au moins partiellement la relation entre les chutes de pluie et la reproduction chez Mastomys .     

Structure and function of pilosebaceous units on the heads of small mammals (Insectivora, Chiroptera, Rodentia)

Haffner, M. 2000. Structure and function of pilosebaceous units on the heads of small mammals (Insectivora, Chiroptera, Rodentia). —Acta Zoologica (Stockholm) 81 : 195–203 The cranial integument of 32 species was examined for increased sebum production and structures serving sebum storage and expulsion by means of light and scanning electron microscopy. The head is rich in sebaceous glands in all species. Some have no further specializations other than regions with enlarged sebum production. These regions either need extra protection per se or they are situated where they can be used for fur grooming directly or be easily reached by the forepaws. The water shrew stores sebum that it can possibly apply as a water‐repellent lipid coating for the fur if required. All vespertilionid bats not only have huge glandular complexes with storage chambers, but also structures for the retaining and application of sebum. Stabilizing elements reflect the extent of external pressure on the specialized pilary canal during sebum discharge. Originally simple hair follicles evolved highly adapted pilosebaceous complexes that possibly produce scent themselves or at least a carrier substance for scent secreted by the many apocrine glands on the snout.     

Primates are an important food resource for leopards (Panthera pardus) in Mahale,Tanzania

Leopard diets in the Kasoje area of the Mahale Mountains National Park, Tanzania, were analysed by inspecting prey remains in 256 scats. This area is unique as leopard density is high despite a relatively low density of medium-sized ungulates, regarded as the most preferred prey of leopards. At least eleven prey mammal species were confirmed in the scats. Small prey mammals up to 10 kg comprised 91.4% of the relative biomass consumed; the mean prey biomass in each scat was 7.6 kg. Blue duiker (31.2%) was the most dominant prey species, followed by the red colobus (29.2%), semi-terrestrial Cercopithecinae (the vervet monkey and yellow baboon combined) (10.5%) and the red-tailed monkey (9.9%). At the order level, the most consumed prey taxon was Primates (53.8%), followed by Cetartiodactyla (39.6%) and Rodentia (5.8%). Among primates, the blue monkey was the most preferred prey species, followed by the red colobus and semi-terrestrial Cercopithecinae. High consumption of primates is a unique characteristic of the leopards in Mahale. This trend exemplifies the flexibility of leopards in their choices of prey, and such flexibility may be one of the underlying reasons for leopards exhibiting the broadest global distribution among all wild felid species.     

Cranial ontogeny of Papio baboons (Papio hamadryas)

Cranial form in subspecies of Papio baboons (Papio hamadryas) varies in relation to size, geography, and sex. However, knowledge about this variation is based mainly on adults, precluding direct assessments of the evolutionary factors that are ultimately responsible for adult shape variation. Consequently, this study tests hypotheses about the development of size and shape differences among subspecies of Papio baboons, anticipating limited evolutionary divergences in the ontogenetic pathways leading to adult endpoints. Geometric morphometric and bivariate allometric analyses are used to explore developmental size and shape variation. Allometric scaling in adult Papio baboons occurs because both sexes and all subspecies follow similar developmental pathways to a variety of adult forms. However, complex allometry contributes to form differences, producing potentially important shape differences that emerge during development. Modest shape differences that are statistically independent of size distinguish chacma baboons (P. h. ursinus) from other forms. A small-headed subspecies, the Kinda baboon (P. h. kindae), also presents a distinctive ontogeny, and may provide insights into the evolution of size change in this species. Variation among subspecies that is statistically independent of size involves the rostrum, zygomatic breadths, and cranial flexion. These features may be related to diet, but the precise biomechanical correlates of baboon form variation remain unclear.     

Occurrence of Hylonycteris underwoodi (Chiroptera,Phyllostomidae) and Thyroptera tricolor (Chiroptera,Thyropteridae) in Honduras

The geographic distributions of Hylonycteris underwoodi and Thyroptera tricolor in Honduras have been established with specimens collected more than 50 years ago. Here, we describe the occurrence of these bat species captured in the historic city of Ciudad Blanca, Gracias a Dios in northeastern Honduras.     

Insect and meat eating among infant and adult baboons (Papio cynocephalus) of Mikumi National Park, Tanzania

It has been suggested that baboon predation upon vertebrates may tend to peak in the dry season because insect food is then less available, and that males obtain animal nutrients primarily from vertebrates whereas other troop members obtain them primarily from invertebrates. The development of meat and insect eating by 22 male and 24 female infants studied for 25 months was compared with that of 18 male and 46 female adults studied for 37 months. Systematic sampling allowed quantitative comparisons between meat and insect eating, infants and adults, and males and females. Infants ate no meat, but their insect eating began early and increased steadily during the first year of life. In comparison with insect foods, meat was a minor ingredient of the adult's diet. Insect eating occurred less during dry than during rainy months, but meat eating was spread across the year. Reliable sex differences in insect eating did not occur. The findings were related to theories offered to explain the attractiveness of animal foods to primates and to the suggestion that a sex difference in predatory inclinations of hominid ancestors may have been a preadaptation underlying the eventual emergence of male hunting and female gathering.     

Hepatocystis in populations of baboons (Papio hamadryas s.l.) of Tanzania and Ethiopia

Bloodsmears from 119 yellow baboons (Papio hamadryas cynocephalus) in six groups in Mikumi National Park, Tanzania, and from 189 olive (P.h. anubis) hamadryas (P.h. hamadryas) and hybrid baboons in three groups in Awash National park, Ethiopia showed differing levels of infection with Hepatocystis simiae. 0% to 42% in the Tanzanian groups were carriers of the parasite but none of the Ethiopian baboons was positive. The remarkable absence of H. simiae in the Ethiopian baboons is believed to be related to environmental factors that exclude transmission in the absence of the Culicoides vector.     

Chromosomal and molecular characterization of Aethomys kaiseri from Zambia and Aethomys chrysophilus from Tanzania (Rodentia, Muridae)

Aethomys is a common and widespread rodent genus in the African savannas and grasslands. However, its systematics and taxonomy are still unclear as no study has covered the entire range. In fact it might not be a monophyletic genus and perhaps should be split into two subgenera, Micaelamys and Aethomys. In this paper, we present findings based on the cytogenetics and the entire cytochrome b sequence of two species from Zambia (A. kaiseri) and Tanzania (A. chrysophilus), and we compare them with the sequences of a South African species (A. namaquensis) and other allied muroid genera. Comparison of the banded chromosomes revealed complete G-band homology between the autosomes of the two species. However, the X and Y chromosomes clearly differ in size and in C- and G-banding, being much larger in A. kaiseri. Comparison of the cytochrome b sequences places the separation between A. kaiseri and A. chrysophilus at 4.49 Mya, a period of intense speciation in other African muroids. The resulting phylogeny strongly supports the idea of a paraphyletic group, suggesting the need to elevate the previously described subgenera to the genus rank.     

Digit Ratios and Dominance in Female Baboons (Papio hamadryas and Papio ursinus)

A growing body of literature suggests that the ratio between the second and fourth digits of the hands (2D:4D ratio) is associated with exposure to prenatal sex hormones in a variety of animals including primates. Female baboons form dominance hierarchies composed of matrilines of related individuals, and the social mechanisms contributing to the structure of these hierarchies have been well studied. We here investigated the relationship between inferred prenatal androgen effects (PAE) and female rank in a captive troop of Hamadryas baboons (Papio hamadryas) with a typical social structure and three captive groups of chacma baboons (Papio ursinus) made up entirely of unrelated orphans. Low 2D:4D ratios (high inferred PAE) were associated with higher-ranking females and high 2D:4D ratios (low inferred PAE) with lower-ranking females in both focal species. This negative correlation between 2D:4D ratio and rank suggests prenatal androgens are linked with the maintenance of female ranks within matrilines in troops with a natural social structure and to the ranks acquired by orphan females.     

First occurrence ofXerus cf.inauris (Rodentia,Sciruridae) at Olduvai Bed I (Lower Pleistocene,Tanzania)

PalZ - Some bonodont molars of a ground squirrel are attributed toXerus cf.inauris. Coming from Olduvai Bed I fossiliferous deposits they could represent an intermediate stage between the Laetoli...