Craniodental body mass estimators in the dwarf bushbaby (Galagoides)

This study reports data on 17 craniodental body mass estimators in a sample (n = 38) of dwarf galagos (Galagoides). Correlation coefficients (r) range from a high of 0.64 for bizygomatic breadth and body mass to a low of 0.10 for M(3) length and body mass. Of the 17 variables studied, 7 exhibit significant (P < 0.05) correlation coefficients, with 5 of the 7 being multitooth (i.e., tooth row) or cranial variables. In contrast to the correlation coefficients of greater than 0.90 (e.g., Martin [1980] Z Morphol Anthropol 71:115-124; Steudel [1981] Int J Primatol 2:81-90; Gingerich et al. [1982] Am J Phys Anthropol 58:81-100; Conroy [1987] Int J Primatol 8:115-137) published for higher taxonomic level analyses (i.e., all-primate or prosimian) for many of the same variables studied here, the current data indicate weaker relationships when analyzed at the generic level. Possible explanations for the contrast in correlation coefficients between the current and many previous studies include the following: 1) individual variation due to a geographically dispersed sample, 2) individual body mass fluctuations due to seasonal food availability, and 3) individual variation within the sample due to variation in life-history parameters. Because the overall size range of the individuals in a specific or generic level analysis is smaller than that in an ordinal or subordinal sample, the individual variation normally masked when using species means represents a larger proportion of the total variation in a more limited sample. This may then be a cause of these weaker correlations.     

Three acoustic forms of Allen's galagos (Primates; Galagonidae) in the Central African region

This study identifies populations currently classified as Allen's galago (Galago alleni) at ten locations in Gabon, Cameroon and Bioko Island. Morphological diversity was evident both within and between populations. Attention to the loud calls revealed three distinct vocal profiles which are consistent within biogeographical regions. This work is based on the Recognition Concept of Species which refers to a Specific Mate Recognition System. Galagos rely less on visual signals than diurnal primates and recognise each other principally by means of auditory and olfactory signals. Galagos possess repertoires of loud calls relating to contact and alarm which are thought to be species-specific. Other studies of nocturnal prosimians (galagos, tarsiers) have demonstrated that the unique loud call repertoires are reliable indicators of species boundaries; whereas characters such as body size and pelage coloration are highly variable, even within populations. The vocal data in this study provide evidence of at least three acoustic forms of galago within the Allen's group which are predicted to represent three distinct species: the Allen's form on Bioko Island and south-west Cameroon, the Gabon form in southern Cameroon and northern Gabon and the Makandé form in Gabon south of the Ogooué river. Some populations may be vulnerable to extinction due to limited distributions and habitat destruction. Electronic Publication     

Body size and scaling of the hands and feet of prosimian primates

The hands and feet of primates fulfill a variety of biological roles linked with food acquisition and positional behavior. Current explanations of shape differences in cheiridial morphology among prosimians are closely tied to body size differences. Although numerous studies have examined the relationships between body mass and limb morphology in prosimians, no scaling analysis has specifically considered hand and foot dimensions and intrinsic proportions. In this study, we present such an analysis for a sample of 270 skeletal specimens distributed over eight prosimian families. The degree of association between size and shape was assessed using nonparametric correlational techniques, while the relationship between each ray element length and body mass (from published data and a body mass surrogate) was tested for allometric scaling. Since tarsiers and strepsirrhines encompass many taxa of varying degrees of phylogenetic relatedness, effective degrees of freedom were calculated, and comparisons between families were performed to partially address the problem of statistical nonindependence and "phylogenetic inertia." Correlational analyses indicate negative allometry between relative phalangeal length (as reflected by phalangeal indices) and body mass, except for the pollex and hallux. Thus, as size increases, there is a significant decrease in the relative length of the digits when considering all prosimian taxa sampled. Regression analyses show that while the digital portion of the rays scales isometrically with body mass, the palmar/plantar portion of the rays often scales with positive allometry. Some but not all of these broadly interspecific allometric patterns remain statistically significant when effective degrees of freedom are taken into account. As is often the case in interspecific scaling, comparisons within families show different scaling trends in the cheiridia than those seen across families (i.e., lorisids, indriids, and lemurids exhibit rather different allometries). The interspecific pattern of positive allometry that appears to best characterize the metapodials of prosimians, especially those of the foot, parallels differences found in the morphology of the volar skin. Indeed, relatively longer metapodials appear to covary with flatter and more coalesced volar pads, which in turn slightly improve frictional force for animals that are at a comparative disadvantage while climbing because of their larger mass. Despite the essentially isometric relationship found between digit length and body mass across prosimians, examination of the residual variation reveals that tarsiers and Daubentonia possess, relative to their body sizes, remarkably long fingers. Such marked departures between body size and finger length observed in these particular primates are closely linked with specialized modes of prey acquisition and manipulation involving the hands.     

Speciation in the greater galagos (Prosimii: Galaginae): review and synthesis*

A marked morphological and genetical discontinuity among the greater galagos points to the existence of two genetical species within the taxon, Galago crassicaudatus E. Geofl'roy 1812. This contribution investigates the conditions surrounding this speciation event, and places it within a phylogenetic context. Information pertaining to body size, litter size, sexual dimorphism, locomotor mode and karyotypic structure is assessed. It is hypothesized that G. crassicaudatus diverged from its more gracile sibling, G. garnettii, approximately 2 million years ago, in respotise lo the increasing aridification of Africa that accompanied the Northern Hemisphere Pleistocene glaciations.     

An assessment of gum-based environmental enrichment for captive gummivorous primates

In the wild, many primates consume gums exuded from trees, and many species are gum specialists. In spite of this, few data exist concerning gum feeding in captivity. Using a web-based survey of 46 zoos in 12 countries, we evaluated the extent to which zoos feed gum to primates. We found that although callitrichids and galagos receive gum-based enrichment, cercopithecines generally do not. Environmental enrichment is important for stimulating naturalistic behavior to promote the psychological wellbeing of animals. Thus, gum-based enrichment is important for captive gummivores. Our study highlights the need to improve environmental enrichment for captive gummivores, in particular that of cercopithecines. This is most striking for the patas monkey (Erythrocebus patas), an obligate gummivore. The exchange of ecological data between field research and captive settings is crucial, and is just one way primate caretakers can contribute to the conservation and welfare of some of our closest living relatives.     

Lack of congruence between morphological and molecular data in reconstructing the phylogeny of the galagonidae.

Published cladistic reconstructions of galagonid phylogeny based on morphological, behavioral, and genetic data have had few elements in common. A recent molecular study indicated that 2 of the 3 generic groupings derived from morphological data were not consistent with tree topologies constructed from the analysis of mitochondrial DNA sequences. In this study, we compiled and analyzed a data set based on craniodental morphology in 13 galagonid and 8 outgroup taxa, comprising 3 dwarf-lemur and 5 loris species, and subjected it to cladistic analysis. Our aim was not only to generate a new phylogenetic hypothesis based on these data, but also to investigate the conditions under which congruence could be achieved between these results and those obtained previously. The data set was found to be highly sensitive to the choice of outgroup, with the lorises showing high interspecific variability in cranial structure. Congruence between the craniodental and molecular trees could be achieved only if Arctocebus was used as the outgroup and two characters were preferentially weighted. Further progress in the reconstruction of galagonid phylogeny will require seeking consensus in a variety of other data sets, including postcranial morphology, behavior, and additional gene sequences. The effect of different outgroups on molecular analysis needs attention.     

Morphological and functional differentiation in the lumbar spine of lorisids and galagids

The striking contrast in positional behavior exhibited by lorisids (slow quadrupedalism/suspension) and galagids (leaping/quadrupedalism) is well reflected in their postcranial morphology, particularly in the limbs. Although they exhibit very different spinal postures and movements, vertebral adaptations have been less well explored in these taxa. This study addressed morphological and functional differentiation in the lumbar vertebrae of four species of lorisids and five species of galagids. Linear and angular measurements of lumbar vertebrae were compared among taxa using canonical variates analysis (CVA) in conjunction with pairwise comparisons among selected variables. The results were interpreted in the context of a broader comparative sample, including the addition of indriids to the CVA. Compared to galagids, lorisids have relatively shorter lumbar spinous processes that are more perpendicularly (to caudally) oriented relative to a coronal plane. Lorisids also have relatively wider laminae and more transversely oriented prezygapophyses. These features promote lumbar stability and reflect antipronogrady, multiplane spinal movements, and upside-down suspension. Within lorisids, vertebral body length and height vary with body size, reflecting the additional resistance to bending that is required for larger body sizes. Galagid lumbar shape is influenced by body size, but does not show strong variation in accordance with positional behavior differences as defined here. Galagids, indriids, and lorisids are distinct in lumbar morphology and function, but their similarities in lumbar length reduction are suggestive of antipronograde postures in the common ancestor of the galagids, including those who have shifted to a more quadrupedal locomotor repertoire.     

Morphological Correlates of Speciation in Bush Babies

Morphology is not a reliable specific indicator in nocturnal animals. Nevertheless, because species are genetically independent, appropriate analytic methods should reveal subtle and consistent morphological differences among them. Until recently, the diversity of living bush babies was underrated, and new species have been recognized on the basis of genetic, behavioral and soft tissue data. This has placed museum curators in a quandary as to how to sort their skin and skull collections according to the new specific designations.We conducted multivariate analyses of 6 morphologically similar pairs of bush baby taxa: Otolemur crassicaudatus and O. garnettii; Galagoides demidoffand G. thomasi; Galago gallarumand G. senegalensis; G. moholi and G. senegalensis; Euoticus elegantulus and E. pallidus, and Galagoides zanzibaricus and G. granti. We also compared subspecies within the taxa Otolemur crassicaudatus, O. garnettii, Galagoides demidoff, and Galago senegalensis. Five out of six species pairs were discriminated with a high level of reliability (88.5–99%) on the basis of 2–5 morphological variables. Only Euoticus elegantulus and E. pallidus did not show this pattern. All strongly supported specific discriminations share two features: (a) ear length is a highly significant factor, while the involvement of other characters is variable; (b) the greater the reliability of the discrimination, the fewer variables necessary to effect it. Euoticus elegantulus and E. pallidus behaved more like subspecies in the discrimination, while Galago senegalensis sspp. showed a pattern of variation similar to that in the specific analyses.     

Highly repeated DNA sequences as phylogenetic markers among the galaginae

Highly repeated DNA sequences were investigated as potential phylogenetic indicators among five species of galagines. One lorisine, one cheirogaleid, and two lemurid species were also investigated as progressively more distant outgroups. The lorisids displayed strong conservatism with regard to these sequences, to the point where the galegine species proved difficult to differentiate. When restriction fragment differences were observed, the galagine species fell into two groups: one containing the greater galagos and G. alleni and the other comprising the lesser galagos. The sequences of the cheirogaleid Microcebus murinus were found to be highly species-specific, bearing little resemblance to those of the galagines or the lemurids. Common sequences detected between M. murinus and G. senegalensis may be ancient sequences shared by all strepsirhines. © 1994 Wiley-Liss, Inc.     

Progressive improvement in the transfer of maternal antibody across the order Primates

Antibody levels were determined in adults and newborn offspring of five primate species. This cross-species comparison of intant IgG levels indicated that prosimians and New World monkeys transfer lower levels of maternal antibody via placental transmission than do Old World monkeys, apes, and humans. The evolutionary trend toward an increased reliance on prenatal antibody transfer in the higher primates appears to be most pronounced in the human infant, because our placenta has evolved an active transport process that elevates IgG in the full-term fetus over maternal levels. Higher IgG levels in the young infant ensure a more prolonged and successful period of passive immunity against pathogens previously encountered by the mother. © 1994 Wiley-Liss, Inc.