Subspecies differences in hormonal and behavioral responses after group formation in squirrel monkeys

The behavioral and hormonal responses of squirrel monkeys of the Bolivian and Guyanese subspecies were compared after a group formation procedure. Two groups of each subspecies, consisting of five females and three males (later reduced to two) were observed daily during the week of group formation and for nine weeks following removal of a single male from each group. Measures of plasma cortisol were examined in the females after the initial group formation and after the groups were reduced by one male. The levels of plasma testosterone were assessed in all the males during the initial week of group formation. Linear dominance hierarchies were determined both within and across the sexes in both subspecies. The frequency and directionality of low-level aggressive interactions indicated that females of the Bolivian subspecies were dominant to the males, while the males of the Guyanese subspecies ranked over all the females. Additionally, the Bolivian squirrel monkey females showed an elevation of plasma cortisol on the day of group formation, which declined 48 hr later, then reelevated after the groups were reduced by one male and declined gradually over a nine-week period. Guyanese females showed little change in cortisol levels during both periods. This suggests fundamental hormonal, as well as behavioral, differences between the two subspecies. The change in plasma testosterone levels in the males during the initial week of group formation was positively correlated with social status. Furthermore, differences in the dynamics within individual groups for each subspecies were reflected by the levels of plasma cortisol of the female members.     

New Genetic Evidence on the Evolution of Chimpanzee Populations and Implications for Taxonomy

Primatologists widely recognize chimpanzees as belonging to a single species, Pan troglodytes, which they traditionally have further divided into 3 subspecies: west African P. t. verus, central African P. t. troglodytes, and east African P. t. schweinfurthii. Previously, we suggested that the phylogeographic history of chimpanzees may be different from that implied by the widely used taxonomy of the species. We based the suggestion on only a limited sample of haplotypes from the first hypervariable region (HVRI) of mitochondrial (mt)DNA from chimpanzees in Nigeria. We have now compiled a more geographically comprehensive genetic database for chimpanzees, including samples obtained near the Niger and Sanaga Rivers. Our database is composed of 254 HVRI haplotypes from chimpanzees of known geographic origin, including 79 unique HVRI haplotypes from chimpanzees living in Nigeria and Cameroon. The genetic data provide clear evidence that a major phylogeographic break between chimpanzee lineages occurs near the Sanaga River in central Cameroon and suggest the need for a reclassification of chimpanzees.     

Further characterization of nuclear DNA RFLP markers that distinguish African and European honeybees

Two nuclear honeybee DNA probes, 12R1C1 and 2A2, were reported previously to detect restriction fragment patterns specific to African and neotropical African honeybee populations. Individual drones and workers from several additional Old and New World populations, African and European, were tested further with these probes. With probe 12R1C1, only two of several Hhal fragment patterns were seen among haploid drone progeny of each queen bee, indicating that the patterns represented alleles at a single locus. Four alleles detected by probe 12R1C1 were described previously, three of which had been found only in populations of African descent. In this study, one of the three was found at a low frequency among samples from western Europe, northern Mexico, and the United States. However, ten additional alleles were discovered in South African drones, six of which were seen also in neotropical African colonies. With probe 2A2, only one or the other of two Alul restriction fragments was detected in drones indicating that the fragments represented alles at a single locus. One of the two alleles, seen previously only in populations of African descent, was found at a very low frequency in bees from western Europe and northern Mexico.     

Evidence of hybrid vigor in subspecific hybrids of the saddle-back tamarin (Saguinus fuscicollis)

The effect of hybridization on infant survival was investigated in subspecific crosses of the saddle-back tamarin (Saguinus fuscicollis) at the Oak Ridge Associated Universities (ORAU) Marmoset Research Center (Oak Ridge, TN). Cox Proportional Hazards Regression was used to compare infant survival between (1) pure subspecies, (2) F1, F2, and backcrossed hybrids, and (3) hybrids and their parental subspecies. Also, effects of management changes, sex, and litter size on infant survival were investigated. There were no significant differences in infant survival between the pure subspecies. Also, degree of hybridization (F1, F2, or backcross) did not have a significant effect on infant survival. Progeny of hybrid crosses between S. f. lagonotus and S. f. illigeri was found to have significantly (P < 0.05) higher infant survival than both of their parental subspecies. Individuals born after diet and management changes in the colony had significantly (P < 0.05) higher survival than those born before. There were no significant sex differences in infant survival. Individuals born into triplet litters had significantly (P < 0.05) lower survival than those born into twin litters. These results show heterosis (hybrid vigor) for infant survival in one subspecific S. fuscicollis cross (S. f. lagonotus × S. f. illigeri). The results suggest genetic divergence between the subspecies populations and possible reproductive isolation in the wild. © 1994 Wiley-Liss, Inc.     

On the distinctiveness of the Cape lion (Panthera leo melanochaita Smith, 1842), and a possible new specimen from the Zoological Museum, Copenhagen

The Cape lion was a population of lions that probably inhabited the western part of the Cape Province of South Africa until their extermination by man in the mid-19th century. Only a few skeletal remains are known, making every specimen valuable. In this paper, I report on a possible new male specimen CN1570 from the Zoological Museum in Copenhagen. A multivariate discriminant analysis on 27 craniodental variables provided clear separation between four of the five lion subspecies (Panthera leo krugeri, nubica, persica, senegalensis) that were included, whereas P. l. bleyenberghi showed some overlap with P. l. senegalensis and P. l. krugeri. The only two undisputed Cape lion males grouped separately from all other lions. CN1570 also grouped separately from other lions, and towards the two Cape lions. The external morphology of the Cape lion is often cited as having been different from other sub-Saharan lions, but phenotypic plasticity argues for caution in placing emphasis on mane morphology as a distinguishing character among lion subspecies. Skull morphology, however, appears to clearly distinguish male Cape lions from other African lions.