Ontogenetic perspective on mechanical and nonmechanical models of primate circumorbital morphology

Dimensions of the supraorbital torus, postorbital bar, and postorbital septum were collected in an ontogenetic series of Macaca fascicularis and compared with expectations based on models that attribute morphological variation in these features to spatial factors, allometry, anterior dental loading, and neurofacial torsion. Each model was evaluated using correlation, partial correlation, and regression techniques (model I/least squares; model II/reduced major axis) applied to log-transformed and size-corrected data. Results indicate clearly that face or skull size is the primary determinant of variation in circumorbital structures. Strong support is found for the influence of spatial influences on anteroposterior supraorbital torus development (Moss and Young, Am. J. Phys. Anthropol. 18:281-292, 1960). Only minor support is noted for the neurofacial torsion model of Greaves (J. Zool. 207:125-136, 1985), and no support is indicated for the anterior dental loading model. The sexes do not differ significantly in any relevant comparisons of ontogenetic trajectories.     

The comparative ultrastructure of the epididymis in monkeys and man: A search for a suitable animal model for studying epididymal physiology in primates

To assess both the need and potential of different primates for studying human epididymal function, the ultrastructure of the epididymis in several New and Old World monkeys has been compared with that of man. Sexually mature monkeys of six species were used; three talapoin monkeys, two pig-tail macaques, one patas monkey, one capuchin, one spider monkey, and four common marmosets. Samples of human epididymis were obtained from men undergoing vasectomy. Tissue was examined by light and electron microscopy and observations were quantified using image analysis. The primate epididymis displayed several ultrastructural features not observed in other mammals. These included the presence of small membrane-bound granules in the infranuclear cytoplasm of principal cells, and a close association of blood capillaries with the basal lamina and mitochondria-rich cells. Differences were apparent in the number and volume of organelles in principal cells from different regions of the epididymis and between species. Epididymal tissue in man showed a much greater ultrastructural diversity than that of monkeys. The significance of these results is discussed in relation to the need for an animal model for studying the primate epididymis.     

Red cell polymorphisms in nonhuman primates: A review

Abstract: Development as well as current status of the knowledge of nonhuman primate blood groups are discussed together with some practical implications of the red cell antigen polymorphisms in anthropoid apes, Old and New World monkeys and prosimians. Recent data on molecular biology and genetics throw light on the relationships among simian and human red cell antigens and their evolutionary pathways.     

Ontogeny and phylogeny in papionin primates

This study investigates the developmental bases of size and shape variation in papionin primates (Macaca, Cercocebus, Mandrillus, Lophocebus, and Papio). The analysis tests hypotheses predicting that heterochronic changes in ontogeny, particularly in the degree of overall size growth, can account for cranial diversity and "allometric scaling" in this clade. Large developmental samples of extant papionin crania are examined to test heterochronic hypotheses using bivariate allometric methods. Analyses indicate that the crania of larger papionins (Mandrillus and Papio) are generally peramorphic, surpassing size and shape ranges of smaller, and probably less-derived, macaques and mangabeys. At least two heterochronic processes, including acceleration and hypermorphosis, can account for this pattern. Ontogenetic changes include decoupling of growth and development among cranial regions, along with simple shifts in size. Allometric scaling has complex developmental bases. Size change itself is not sufficient to explain all developmental differences among papionins, but these changes are extremely important in comparisons within cranial regions such as the face. Results imply that Papio exhibits strongly derived patterns of brain growth that impact postnatal patterns of size and shape transformation. Consideration of these results in the context of recent socioecological analyses suggests that derived patterns of cranial growth in Papio may be a response to selection during the early periods of ontogeny, resulting in a distinctive life history pattern.     

Homoplasy and the evolution of ontogeny in papionin primates

Recent advances in developmental biology reveal that patterns of morphological development, even during early phases, may be highly susceptible to evolutionary change. Consequently, developmental data may be uninformative with regard to distinguishing homology and homoplasy. The present analysis evaluates postnatal ontogeny in papionin primates to test hypotheses about homology and homoplasy during later periods of development. Specifically, the analysis studies the allometric bases of craniometric resemblances among four papionin genera to test the hypothesis that homoplasy in adult cranial form, particularly of baboons (Papio) and mandrills (Mandrillus), is underwritten by divergent patterns of development. Bivariate and multivariate allometric analyses demonstrate that the developmental patterns in Papio baboons diverge markedly from ontogenetic allometric trajectories in other papionin species. The resemblances between Papio and Mandrillus (assuming that patterns of development in smaller papionins are ancestral) are largely consequences of perinatal increases in relative brain size in juvenile Papio. Postnatal growth to large size and strong negative allometry of neurocranial form results in shape similarities because developmental pathways for large papionin genera intersect. Analyses show that allometric data may not be particularly informative in revealing homoplasy. However, placed into proper phylogenetic context, such data illustrate derived patterns of development that may reflect critically important life-history or ontogenetic adaptations.     

Baseline and stress levels of cortisol in conscious and unrestrained Japanese macaques (Macaca fuscata)

A vest and tethering system was applied to Japanese macaques (Macaca fuscata) to collect blood samples under less stressful conditions. The level of plasma cortisol was assayed to assess the amount of stress. The pattern of plasma cortisol fluctuation during 24 hours was consistent under non-stress conditions. The plasma cortisol level was increased significantly by encounter and venipuncture. The increase was especially noteworthy when the experimental macaques encountered a large adult male, reflecting the strong stress on macaques. As venipuncture is a common medical procedure, and the encounter between macaques who have never met before occurs frequently, this vest and tethering system is useful for the assessment of the amount of stress in the daily care of macaques in a laboratory.     

Proteogenomic review of the changes in primate apoC-I during evolution

Apolipoprotein C-I has evolved more rapidly than any of the other soluble apolipoproteins. During the course of primate evolution, the gene for this apolipoprotein was duplicated. Prompted by our observation that the two resulting genes encode two distinct forms of apoC-I in great apes, we have reviewed both the genomic and proteomic data to examine what changes have occurred during the course of primate evolution. We have found data showing that one of the duplicated genes, known to be a pseudogene in humans, was also a pseudogene in Denisovans and Neandertals. Using genomic and proteomic data for primates, we will provide in this review evidence that the duplication took place after the divergence of New World monkeys from the human lineage and that the formation of the pseudogene took place after the divergence of the bonobos and chimpanzees from the human lineage.     

Paranasal pneumatization in extant and fossil Cercopithecoidea

Unlike most primates, extant cercopithecoids lack maxillary sinuses, which are pneumatic spaces in the facial skeleton lateral of the nasal cavity proper. Character state analysis of living cercopithecoids across well-supported topologies suggests that the sinus was lost at the origin of the superfamily, only to have evolved again convergently in extant macaques. Recent work has shown that a) the 'early loss' hypothesis is supported by the lack of any pneumatization in Victoriapithecus, a stem cercopithecoid, b) like extant macaques, the fossil cercopithecine Paradolichopithecus shows evidence of presence of the maxillary sinus (MS), and c) unlike extant colobines, the fossil colobine Libypithecus also possesses a maxillary sinus. To more fully assess the pattern of cercopithecoid sinus evolution, fossil taxa from both subfamilies (Colobinae, Cercopithecinae) were examined both visually and by computed tomography (CT). The observations were evaluated according to standard anatomical criteria for defining sinus spaces, and compared with data from all extant Old World monkey genera. Most taxa examined conformed to the pattern already discerned from extant cercopithecoids. Maxillary sinus absence in Theropithecus oswaldi, Mesopithecus, and Rhinocolobus is typical for all extant cercopithecids except Macaca. The fossil macaque Macaca majori possesses a well-developed maxillary sinus, as do all living species of the genus. Cercopithecoides, on the other hand, differs from all extant colobines in possessing a maxillary sinus. Thus, paranasal pneumatization has reemerged a minimum of two and possibly three times in cercopithecoids. The results suggest that maxillary sinus absence in cercopithecoids is due to suppression, rather than complete loss.     

Mitochondrial cytochrome b gene sequences of old world monkeys: With special reference on evolution of Asian colobines

The classification and phylogenetic relationships of the Old World monkeys are still controversial. For Asian colobines, from three to nine genera were recognized by different primatologists. In the present study, we have sequenced a 424 bp mitochondrial tRNA^Thr gene and cytochrome b gene fragment fromMacaca mulatta, Mandrillus sphinx, Mandrillus leucophaeus, Semnopithecus entellus, Trachypithecus vetulus, T. johnii, T. phayrei, T. francoisi, Pygathrix nemaeus, Rhinopithecus roxellanae, R. bieti, R. avunculus, Nasalis larvatus, andColobus polykomos in order to gain independent information on the classification and phylogenetic relationships of those species. Phylogenetic trees were constructed with parsimony analysis by weighting transversions 5 or 10 fold greater than transitions. Our results support the following conclusions: (1) the Old World monkeys are divided into two subfamilies; (2) that among the colobines,Colobus, the African group, diverged first, andNasalis andRhinopithecus form a sister clade toPygathrix; (3) that there are two clades within leaf monkeys, i.e. 1)S. entellus, T. johnii, andT. vetulus, and 2)T. phayrei andT. francoisi; (4) thatRhinopithecus avunculus, R. roxellanae, andR. bieti are closely related to each other, and they should be placed into the same subgenus; (5) thatRhinopithecus is a distinct genus; and (6) that the ancestors of Asian colobines migrated from Africa to Asia during the late Pliocene or early Pleistocene.     

Routine DNA analysis based on 12S rRNA gene sequencing as a tool in the management of captive primates

Automated DNA sequencing of a fragment of the relatively slowly evolving mitochondrial 12S rRNA gene was used to distinguish primate species, and the method was compared with species determination based upon classical taxonomy. DNA from blood from 53 monkeys housed at the Stichting AAP Shelter for Exotic Animals, all Old World monkeys, was amplified by polymerase chain reaction (PCR) with a primer set spanning approximately 390 nucleotides of the mitochondrial 12S rRNA gene. The products were directly sequenced and compared with our database of primate 12S sequences. Many individuals were found to harbor a 12S sequence identical to one of the reference sequences. For others, phylogenetic methods were used for species estimation, which was especially informative in Cercopithecus species.     

The subfossil monkey femur and subfossil monkey tibia of the Antilles: A review

The proximal portion of a subfossil monkey femur found in a Jamaican cave shares all the femoral characters of a mature male Cebus apella.The fragment alone, however, does not prove conspecificity. The Jamaican femur is also of a size that could belong to the extinct Xenothrix mcgregoriof the same island. In contrast, the distal portion of a monkey tibia recovered from a kitchen midden in the Dominican Republic cannot be identified with that of any known living platyrrhine or catarrhine monkey. Geological age, geographic locality, and size of fragment point to probable alignment of the tibia with the recently extinct cebid Saimiri bernensis.Although no conclusive identifications are made, the distinctive characters of the two limb bones are described on the basis of comparisons with femurs and tibias representing all genera of living platyrrhines, most genera of catarrhine monkeys, and some strepsirhines.     

Distribution of dorsal carriage among simians

We surveyed the literature and obtained information from primate researchers and zookeepers to study the distribution of dorsal carriage among 77 simian species including New and Old World monkeys and apes in relation to arboreality and terrestriality, birth (litter) weight relative to maternal weight, and presence or absence of distinct natal coat colors. All New World monkeys are arboreal and commonly carry their infants dorsally. Conversely, arboreal Old World monkeys do not use dorsal carriage, and only some predominantly terrestrial Old World monkeys do so. Whereas lesser apes (which are highly arboreal) do not use dorsal carriage, arboreal as well as more terrestrial great apes commonly carry their infants dorsally. These findings indicate that simple arboreality or terrestriality is inadequate to explain dorsal carriage by monkeys. Infants of small- to medium-sized New World monkeys have relatively high birth weight compared with maternal weight, and are most likely to be carried dorsally than ventrally even on the first postnatal day. In contrast, infants of large-bodied New World monkeys are carried ventrally first and then dorsally up to the end of their second year, albeit increasingly infrequently. Among Old World monkeys, no association was found between mode of infant transport and birth weight relative to maternal weight, but some terrestrial Old World monkeys displaying dorsal carriage tend to do so with older infants, indicating that such behavior enables the mother to transport the infant with lower energy expenditure. Among terrestrial Old World monkeys, infants with distinctive natal coat colors are rarely carried dorsally until the natal coat color changes to adult coloration: infants with distinctive coat colors clinging to the backs of carriers could be highly visible and thus vulnerable to predation. Dorsal carriage by mothers may prolong the affiliative mother–infant relationship.     

The response of catarrhine primates to pleistocene environmental fluctuations in East Asia

Examination of the patterns of distribution for five catarrhine genera (Gigantopithecus, Pongo, Hylobates, Macaca, andRhinopithecus) during the Pleistocene and Holocene in China indicates that the geographical ranges of individual genera shifted independently of one another in response to conditions of increasing seasonality. All genera examined saw their distributions shift southward, with the shifting subtropical and tropical zones, during the Pleistocene. This occurred earlier in the Pleistocene for the larger apes, and later for smaller forms. This apparent paradox is readily explained by the inability of large-bodied apes to satisfy the high metabolic demands of a relatively large brain as well as those of an absolutely larger body. Monkeys were somewhat less affected and their greater relative success is attributed to their abilities to survive in more highly seasonal environments by exploiting a wider variety of plant foods and to produce offspring more quickly, thanks to shorter gestation times and shorter interbirth intervals.     

Distribution of U5 antigen on lymphocyte subsets in human and nonhuman primates

The U5 monoclonal antibody developed by immunizing mice with Japanese monkey lymphocytes could react with lymphocytes of primate species including Old World monkeys, apes, and human. However, the distributions of U5 antigen on major functional subsets of lymphocytes were different in primate species. The U5 antigen was mainly distributed on natural killer (NK) cells in human, but on B cells in Old World monkeys. On the other hand, U5 antigen was detected on both B and NK cells in chimpanzees and gibbons, indicating that the distribution of U5 antigen on lymphocyte might change from B cells to NK cells during primate evolution.     

Covariance structure in the skull of Catarrhini: a case of pattern stasis and magnitude evolution

The study of the genetic variance/covariance matrix (G-matrix) is a recent and fruitful approach in evolutionary biology, providing a window of investigating for the evolution of complex characters. Although G-matrix studies were originally conducted for microevolutionary timescales, they could be extrapolated to macroevolution as long as the G-matrix remains relatively constant, or proportional, along the period of interest. A promising approach to investigating the constancy of G-matrices is to compare their phenotypic counterparts (P-matrices) in a large group of related species; if significant similarity is found among several taxa, it is very likely that the underlying G-matrices are also equivalent. Here we study the similarity of covariance and correlation structure in a broad sample of Old World monkeys and apes (Catarrhini). We made phylogenetically structured comparisons of correlation and covariance matrices derived from 39 skull traits, ranging from between species to the superfamily level. We also compared the overall magnitude of integration between skull traits (r²) for all Catarrhini genera. Our results show that P-matrices were not strictly constant among catarrhines, but the amount of divergence observed among taxa was generally low. There was significant and positive correlation between the amount of divergence in correlation and covariance patterns among the 30 genera and their phylogenetic distances derived from a recently proposed phylogenetic hypothesis. Our data demonstrate that the P-matrices remained relatively similar along the evolutionary history of catarrhines, and comparisons with the G-matrix available for a New World monkey genus (Saguinus) suggests that the same holds for all anthropoids. The magnitude of integration, in contrast, varied considerably among genera, indicating that evolution of the magnitude, rather than the pattern of inter-trait correlations, might have played an important role in the diversification of the catarrhine skull.     

The emissary foramina: Their value in platyrrhine systematics

A discriminant analysis was performed on 226 ceboid skulls using data on emissary foramina size and shape. The purposes of the study are to 1) measure the success with which these discriminating variables can distinguish among platyrrhine genera and 2) derive a set of classification functions which will permit the classification of new cases with unknown group membership (i.e., fossil skulls). This technique is able to correctly classify 80% of the 226 ceboid skulls. Support is given to the allocation of Chiropotes, Cacajao, and Pithecia into one morphologically unified subfamily, Pitheciinae. Alouatta, Ateles, and Lagothrix also share many similarities in emissary foramina size and shape and their inclusion into one subfamily, Atelinae, is probably warranted. The distinctiveness of Cebus in these same morphological features is apparent. Possibilities for extending this procedure to study fossil lineages in platyrrhines are discussed.     

Age‐specific fecundity of mammalian populations: A test of three mathematical models

Empirical age‐specific fecundity distributions are often based on small samples and hence include high levels of sampling error, particularly at the older ages. One solution to this problem is to smooth the distributions using appropriate models. The aim of this article is to compare the utility of three models for smoothing and/or graduating these distributions. The three models examined are 1) the Gamma distribution, 2) the Hadwiger function, and 3) the Brass polynomial. Test data sets consist of four types of primates (including humans), Asian elephants, and Przewalski’s horse (an extinct species). The results indicate that all three models work well with a variety of mammalian data. The simplest of these models, the Brass polynomial, cannot be rejected based on available data and appears to be the optimum choice. Zoo Biol 20:487–499, 2001. © 2002 Wiley‐Liss, Inc.     

Translational models of tumor angiogenesis: A nexus of in silico and in vitro models

Emerging evidence shows that endothelial cells are not only the building blocks of vascular networks that enable oxygen and nutrient delivery throughout a tissue but also serve as a rich resource of angiocrine factors. Endothelial cells play key roles in determining cancer progression and response to anti-cancer drugs. Furthermore, the endothelium-specific deposition of extracellular matrix is a key modulator of the availability of angiocrine factors to both stromal and cancer cells. Considering tumor vascular network as a decisive factor in cancer pathogenesis and treatment response, these networks need to be an inseparable component of cancer models. Both computational and in vitro experimental models have been extensively developed to model tumor-endothelium interactions. While informative, they have been developed in different communities and do not yet represent a comprehensive platform. In this review, we overview the necessity of incorporating vascular networks for both in vitro and in silico cancer models and discuss recent progresses and challenges of in vitro experimental microfluidic cancer vasculature-on-chip systems and their in silico counterparts. We further highlight how these two approaches can merge together with the aim of presenting a predictive combinatorial platform for studying cancer pathogenesis and testing the efficacy of single or multi-drug therapeutics for cancer treatment.