Comparative anatomy of the tongue of Pan troglodytes (Blumenbach, 1799) and other primates. II. Findings in other primates

This 2nd part of our studies shows that the papilla foliata is fully developed in Pan, Cebus, and Macaca; in Prosimians the papilla foliata is well developed in Lemur and Chirogaleus. In Galago crassicaudatus, this papilla is missing. Among 3 individuals of Microcebus, the papilla foliata was differently developed: in 2 cases, the tongue exhibited only 2 on both sides and a very low folia. Taste buds were found in the epithelium of only one side of each folium. In the 3rd case, the folia of the papilla were developed only on one side of the tongue, whereas, on the other side, a typical papilla was missing. Instead of the papilla, the tongue of the same animal exhibited a hillock-like structure; it is a gustatory hillock which exhibited many taste buds. There were 3 gustatory hillocks in all of the specimens of Tupaia glis; they are situated on both sides of the tongue.     

Mhc-DRB diversity of the chimpanzee (Pan troglodytes)

Fifty-four chimpanzee Patr-DRB and five human HLA-DRB second exons were cloned and sequenced from thirty-five chimpanzees and four B-cell lines and compared with known Mhc-DRB sequences of these two species. Equivalents of the HLA-DRB1 ^* 02,-DRB1 ^* 03, -DRB1 ^* 07 allelic lineages and the HLA-DRB3,-DRB4, -DRB5, -DRB6, and -DRB7 loci were all found in the chimpanzee. In addition, two chimpanzee Patr-DRB lineages (Patr-DRBX and -DRBY) were found for which no human counterparts have been described. None of the Patr-DRB sequences is identical to known HLA-DRB sequences. The Patr-DRB1 ^* 0702 and HLA-DRB1 ^* 0701 alleles are the most similar sequences in a comparison between the two species and differ by only two nucleotides out of 246 sequences. Equivalents of the HLA-DRB1 ^* 01,-DRB1 ^* 04, and -DRB1 ^* 09 alleles were not found in our sample of chimpanzees. A per locus comparison of the number of Patr-DRB alleles with the HLA-DRB alleles shows that the Patr-DRB3, -DRB4, -DRB5, and -DRB6 locus are, thus far, more polymorphic than ther human homologs. The polymorphism of the Patr-DRB1 locus seems to be less extensive than that reported for the HLA-DRB1 locus. Nevertheless, the Patr-DRB1 locus seems to be the most polymorphic of the Patr-DRB loci. Phylogenetic analyses indicate that the HLA-DRB1 ^* 09 allele may have originated from a recombination between a Mhc-DRB5 allele and the DRB1 allele of a Mhc-DR7 haplotype. Although recombination seems to increase the diversity of the Patr-DRB alleles, its contribution to the generation of Patr-DRB variation is probably low. Hence, most Patr-DRB diversity presumably accumulated via recurrent point mutations. Finally, two distinct PAtr-DRB haplotypes are deduced, one of which (the chimpanzee equivalent of the HLA-Dr7 haplotype) is probably older than 6–8 million years.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide database and have been assigned the accession numbers Mg6074-Mg6132. Correspondence to: M. Kenter.     

Perinatal dental development in the chimpanzee (Pan troglodytes)

The synthesis of both ontogenetic and phylogenetic data should provide the ideal explanation of morphologic variation, but for the primate dentition, this has not yet occurred. Information concerning growth and development of primate teeth is lacking, in part because of the paucity of specimens. We have therefore examined the deciduous second molars (dm2) and tooth buds of the permanent first molar (M1) of 12 chimpanzees (Pan troglodytes), aged 6.5 months of gestation to 4 postnatal months. The ordering of cusp calcification was identical to that of other primates. By regression analysis, correlations of mesial and distal widths with buccal, lingual, and mesiodistal lengths were low, most probably because of decreased rates of change (slopes) and the relatively small sample size. Correlations were, however, greater for mandibular than for maxillary dentition and higher for age than for body weight; for both the dm2 and M1, distal moieties increased faster and were more highly correlated with other dental variables and age than were mesial ones. Comparison with data from humans revealed both differences and similarities in the absolute size and growth rate of dental moieties during the perinatal period. As the reasons for ontogenetic variation become understood for individuals, species, and higher taxa, the phylogenetic implications of differential growth should become clearer as well.     

Predation on mammals by the chimpanzee (Pan troglodytes)

With respect to prey selectivity and predation frequency, chimpanzees (Pan troglodytes) show local differences as well as diachronic variability within the same population. When data on predation from three long-term studies at Mahale, Gombe, and Tai are compared, some differences and similarities emerge; Mahale is more like Gombe than Tai in regard of prey selection but features of hunting at Tai with respect to predation frequency are not conspicuous. The most responsible factor for diversity in prey selectivity is a distinct “prey image” maintained by chimpanzees of different populations, although it is necessary to clarify in future studies why and how such tradition develops. Relative body size of chimpanzees to prey species and/or the degree of cooperation among members of a hunting party may explain the variability in prey size selected at each site, the latter influencing the frequency of successful hunts at the same time. Although various degrees of habituation and different sampling methods including artificial feeding might have obscured the real differences, recent data from the three populations do not seem to be biased greatly by such factors. Nevertheless, it is still difficult to make strict comparisons due to the lack of sufficient standardized data across the three populations on the frequency of hunting and predation. It is suggested that the size or demographic trend of a chimpanzee unit-group, especially the number of adult males included, necessarily influences its hunting frequency as well as its prey profile. It is also suggested that factors which bring these males together into a party (e.g. fruit abundance, swollen females, conflict between unit-groups etc.) strongly affect theactual hunting and kill rates. Other possible factors responsible for the local differences are forest structure (e.g. tree height), skilful “hero” chimpanzees, and competition with sympatric carnivorous animals. A total of at least 32 species have been recorded as prey mammals of chimpanzees from 12 study sites and the most common prey mammals are primates (18 species), of which 13 species are forest monkeys. Forest monkeys, colobine species in particular, are often the most common victims of the predation by chimpanzees at each site. We may point out a tendency toward selective hunting for the forest monkeys in terms of the selectivity of prey fauna among all three subspecies of chimpanzees, including populations living in drier environment. The mode of chimpanzee hunting seems to correspond to the highest available biomass of gregarious, arboreal monkeys in the forest, colobine species in particular. In contrast, bonobos (P. paniscus) are less carnivorous than chimpanzees, only rarely preying on a few species of small mammals. The sharp contrast of the two allied species in their predatory tendencies appears to have something to do with the differences in the structure of primary production between their habitats.     

Functional analysis of chimpanzee (Pan troglodytes) private signing

The chimpanzee's use of American Sign Language (ASL) to communicate with humans and with each other has been empirically demonstrated in several reports, but this is the first research to experimentally examine their use of sign language in a nonsocial fashion: private signing. This experiment examined the private signing behavior of five signing chimpanzees, using a remote videotaping technique with no human present. It was found that all five chimpanzees signed to themselves for a total of 368 instances. These instances of private signing were classified into nine different functional categories as has been done in the analysis of private speech and signing in hearing and deaf human children. Similar to humans, a few of the categories accounted for the majority of the instances of private signing. These findings empirically demonstrate a behavior similar to private speech and signing in humans.     

Semen characteristics of the adult male chimpanzee (Pan troglodytes)

The chimpanzee, because of its similarities to the human, is especially valuable in studies of reproductive function. However, relatively little is known about the physiology of reproduction in the adult male chimpanzee. This study provides, for five adult male chimpanzees, baseline values for testicular volume without and with pressure and for cellular and biochemical characteristics of ejaculates collected by artificial vagina (AV). There was no correlation between body weight and testicular volume measured without or with pressure. The ratios of mean testicular volume without and with pressure were not statistically different among animals. Statistical analysis of penetration of denuded hamster oocytes by ejaculated chimpanzee sperm revealed no correlations between sperm count and percentage of eggs penetrated. There was significant variability in concentrations of protein and fructose and in activities of alpha-glucosidase and acid phosphatase among samples from different animals. Computer-assisted motion analysis (CAMA) of sperm provided baseline data on motion parameters necessary for future evaluation of this technique for semen analysis in the chimpanzee. The level of demonstrated inter-animal variation mandates use of each animal as its own control for studies on normal and altered reproductive function. © 1993 Wiley-Liss, Inc.     

Diagrammatic representation for chromosomal mutagenesis studies. III. Radiation-induced rearrangements in Pan troglodytes (chimpanzee)

A qualitative study is presented of chromosomal rearrangements induced by gamma-irradiation at 2 Gy and 3 Gy in peripheral blood lymphocytes of the chimpanzee Pan troglodytes. From a sample of 460 cells, karyotyped after R-banding, 1047 rearrangements were detected. Each type of rearrangement is analyzed according to the diagrammatic method previously developed. The non-random nature of the induction of the rearrangements is clear. The chimpanzee seems highly sensitive to the induction of dicentrics. This may be related to the existence, in its karyotype, of sensitive juxta-telomeric heterochromatin, much more frequently affected in the case of formation of dicentrics than of other types of rearrangements. Thus, the evaluation of radiation sensitivity of a given species based only on the yield of dicentrics may not have a general value for chromosomal mutagenesis.     

Spontaneous heart disease in the adult chimpanzee (Pan troglodytes)

Background  A high incidence of heart disease, especially idiopathic cardiomyopathy (IC), is seen in chimpanzees ( Pan troglodytes ).
Methods  We reviewed clinical records and necropsy reports of 87 adult chimpanzees for possible causes of heart disease/IC. We examined age, sex, cause of death, weight, diet, environment, infectious diseases, experimental uses and clinical pathology.
Results  The overall prevalence of heart disease in chimpanzees was 67.81%; the prevalence of IC was 51.72%. The prevalence of IC was significantly higher in males (60.32%) than that in females (29.17%, P  = 0.009). The prevalence of other heart disease was higher in females (25%) than that in males (12.70%, P  = 0.165). Heart failure occurred in 47.13% of chimpanzees. Heart disease was the primary cause of death in 34.49% of chimpanzees; 29.88% died of unknown causes.
Conclusions  We found no evidence that diet, environment, viral agents, experimental use or disease exposure contributed to the deaths resulting from IC in chimpanzees.     

Expression of beta-defensin-1 in chimpanzee (Pan troglodytes) airways

In human airways, beta-defensins function in the elimination of various pathogens. They have been identified in a wide range of species. Here we report the identification and expression of chimpanzee beta-defensin-1 (cBD1), which is a homolog of human beta-defensin-1, in chimpanzee airways and skin. The cBD1 cDNA sequence differs by only one synonymous nucleotide substitution compared to the human cDNA sequence. In situ hybridization revealed that in lung tissue beside alveolar macrophages also airway epithelial cells, endothelial cells and type II pneumocytes express cBD1 mRNA. In skin, cBD1 mRNA was expressed in keratinocytes and endothelial cells. Together, these results show similarity in structure and expression pattern and perhaps in function.     

Localization of rDNA in the chimpanzee (Pan troglodytes) chromosome complement

In situ hybridization was used to identify the sites of rDNA in the chromosome complement of the chimpanzee (Pan troglodytes). The rDNA was present in the satellite regions of chimpanzee chromosomes 14, 15, 17, 22 and 23. Four of these (14, 15, 22, 23) are homologous to human chromosomes carrying rDNA: 13, 14, 21 and 22.     

Treatment regimen for air sacculitis in the chimpanzee (Pan troglodytes)

Six champanzees (Pan troglodytes) developed air sacculitis. Except for air sac distension and malodorous breath, clinical signs were rare. A variety of organisms, mainly enteric, were isolated from the air sacs. Only one case was treated surgically. Other cases were treated by the conservative method of irrigation which worked well.     

Placental implications for pregnancy complications in the chimpanzee (Pan troglodytes)

Placentas from 28 term chimpanzee pregnancies, including two sets of dichorionic-diamniotic twin-pregnancies, were examined and compared histopathologically with those obtained from 171 small-for-dates (SFD), 306 premature, and 77 pregnancy toxemic human infants. Term infant and placental weights for the chimpanzee were generally smaller than for any of the human categories studied. Macroscopically, the chimpanzee placentas showed a high frequency of extrachorialis, infarctions, intervillous thrombi, and marginal hemorrhages, pathologies frequently associated with pregnancy toxemia and abruptio placenta in the human being. Yet, ultrastructurally, the chimpanzee chorionic villi evidenced well-developed organella, syncytial microvilli, and chorionic capillaries, although villitis and inflammation of the membranes and cord were not infrequently seen. These findings suggest that chimpanzees may suffer the same obstetric complications seen in human pregnancies.     

Muscle architecture of the common chimpanzee (Pan troglodytes): perspectives for investigating chimpanzee behavior

Thorpe et al. (Am J Phys Anthropol 110:179–199, 1999) quantified chimpanzee (Pan troglodytes) muscle architecture and joint moment arms to determine whether they functionally compensated for structural differences between chimpanzees and humans. They observed enough distinction to conclude that musculoskeletal properties were not compensatory and suggested that chimpanzees and humans do not exhibit dynamically similar movements. These investigators based their assessment on unilateral limb musculatures from three male chimpanzees, of which they called one non-adult representative. Factors such as age, sex, and behavioral lateralization may be responsible for variation in chimpanzee muscle architecture, but this is presently unknown. While the full extent of variation in chimpanzee muscle architecture due to such factors cannot be evaluated with data presently available, the present study expands the chimpanzee dataset and provides a preliminary glimpse of the potential relevance of these factors. Thirty-seven forelimb and 36 hind limb muscles were assessed in two chimpanzee cadavers: one unilaterally (right limbs), and one bilaterally. Mass, fiber length, and physiological cross-sectional area (PCSA) are reported for individual muscles and muscle groups. The musculature of an adult female is more similar in architectural patterns to a young male chimpanzee than to humans, particularly when comparing muscle groups. Age- and sex-related intraspecific differences do not obscure chimpanzee-human interspecific differences. Side asymmetry in one chimpanzee, despite consistent forelimb directional asymmetry, also does not exceed the magnitude of chimpanzee-human differences. Left forelimb muscles, on average, usually had higher masses and longer fiber lengths than right, while right forelimb muscles, on average, usually had greater PCSAs than left. Most muscle groups from the left forelimb exhibited greater masses than right groups, but group asymmetry was significant only for the manual digital muscles. The hind limb exhibited less asymmetry than the forelimb in most comparisons. Examination of additional chimpanzees would clarify the full range of inter- and intra-individual variation.     

Dental variability of the Liberian chimpanzee,Pan troglodytes verus

Dental variability was studied in a collection of Liberian chimpanzee (Pan troglodytes verus) crania from one geographic area of Central Liberia. Morphological and metric data were compared to another population of the same subspecies studied by Schuman and Brace (1955) as well as to other pongid taxa. It appears that of all living pongids, chimpanzees are the most derived in their lower molar patterns, particularly, P. t. verus. It is clear, however that the mandibular molar patterns of contemporary chimpanzees are more similar to other pongids that to humans which is contra to the suggestions of Schuman and Brace. Hypocone reduction from M1 to M3 is the common pattern in all hominoids. Complete absence of the M3 hypocone is rare in pongids but it is present in the Frankfurt collection. Of living pongids, the gorilla expresses the least amount of hypocone reduction from M1 to M3. A cusp of Carabelli is recorded bilaterally in one P.t. verus. There is less odontometric variation in P.t. verus than in other pongids as indicated by the CV’s which may suggest the greater dental variability present when different geographic groups are included in the sample.     

A comparison of the fluorescent karyotypes of the chimpanzee (Pan troglodytes) and man

Individual chimpanzee chromosomes have been identified by their characteristic banding revealed by quinacrine fluorescent staining. A fluorescent karyotype of this species was set up to be compared with the standard human fluorescent karyotype. It was found that chromosomes 1, 3, 11, 12, 14 and X-chromosome of the chimpanzee appear to have banding patterns similar to the equivalent human chromosomes. Chromosomes 6, 7, 8, 10 and 13 also had a fluorescent pattern corresponding to the human chromosomes of the same number, particularly in the long arm. Remarkable variation in intensity and/or size of fluorescent regions was frequently found in the short arm of satellited acrocentric chromosomes 13, 14, 15, 22 and 23. Variations occurred between homologues and between individuals. Such variable fluorescence in a specific chromosomal region of an individual animal is a reproducible characteristic. Unlike its human counterpart, the distal segment in the long arm of the chimp's Y-chromosome is not brightly fluorescent. An earlier report is thus confirmed.     

Case report on the death of a wild chimpanzee (Pan troglodytes verus)

The present paper gives a case report on the death of a wild young chimpanzee (Pan troglodytes verus) at Bossou, Guinea. The corpse of a 6.5-year-old male was found, and an autopsy suggested that he had died from some non-epidemic disease or from poisoning. Morphological measurements of the skeleton revealed that the chimpanzee was much smaller than corresponding individuals in captivity. The dental formula of the chimpanzee coincided with those of 5- to 5.5-year-olds in captivity. The death of this chimpanzee suggests that some of the individuals who had disappeared at Bossou had died of natural causes.