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A study was undertaken of a unique sample of 63 wild vervet monkeys Cercopithecus aethiops from a single population in Uganda collected over 35 days in 1947. Twenty-five were immature (12 females and 13 males) and 38 were adults (16 females and 22 males). Body mass, external measurements, masticatory and other masses were recorded for each individu...
Context in source publication
Context 1
... differences (masseter: ANOVA, F 1,17 = 4.172, P = 0.056; temporalis: ANOVA, F 1,17 = 3.952, P = 0.062). As adults, females are significantly less muscular than the males (masseter: ANOVA, F 1,29 = 92.95, P < 0.001); temporalis: ANOVA, F 1,29 = 142.01, P < 0.001). When considered by age class, the difference appears during age class 6 (see Fig. ...
Citations
... The collated submissions were uploaded to a common web drive the month before the workshop. 3,6,12,[37][38][39][40][41][42][43][44][45][46][47][48][49] The first evening of the workshop was an informal meet and greet of our participants, as many did not know each other. ...
... We report age scores rather than estimates of chronological age because of the amount of variation in timing of primate tooth eruption (Bolter & Zihlman, 2003;Harvati, 2000;Hlusko & Mahaney, 2009;Jogahara & Natori, 2012;Monson & Hlusko, 2018). ...
Objectives
The goals of this study were to describe and interpret two new fossil assemblages of cercopithecin monkeys ( n = 328), one from the Faro Daba beds (ca. 100,000 years) and the other one from the Chai Baro beds (>158,000 years old), in the Afar Rift of Ethiopia.
Materials and Methods
We describe the two assemblages and compare them to extant cercopithecin species and the smaller fossil assemblage from Asbole, Ethiopia (ca. 600 ka). We use a population‐based approach to the taxonomy given the unusually large number of specimens. Craniodental and postcranial anatomy are presented. Evidence of locomotor habitus is described and evaluated in a framework of hybridization and postcranial plasticity.
Results
We attribute all cercopithecin specimens from both beds to cf. Chlorocebus and conclude that the Faro Daba and Chai Baro assemblages likely sample single species at each time horizon. Subtle differences between the two assemblages, mostly in postcranial morphology, are insufficient to justify separation at the species level.
Discussion
The large sample sizes and unique preservational aspects of these two assemblages open a new window into the recent evolution of guenons. Our data indicate that these fossil populations may be ancestral to the cercopithecins currently living in the Afar region of Ethiopia.
... Stage 1 individuals were edentulous newborns, Stage 2 spanned the period of time during which the deciduous dentition erupted until the eruption of the first maxillary molar, Stage 3 beginning at the eruption of the first maxillary molar and ending at the eruption of the second maxillary molar, Stage 4 beginning at the eruption of the second permanent maxillary molar and ending at the eruption of the third maxillary molar, and Stage 5 beginning at either the eruption of the third maxillary molar or the obliteration of the sphenooccipital synchondrosis. These growth stages have been used previously in studies of basicranial and facial development and are known to correspond to periods of largescale cranial growth changes (Ashton, 1957;Bolter & Zihlman, 2003;Hellman, 1927;Laitman et al., 1979;Pagano et al., 2017Pagano et al., , 2019. ...
The late archeologist Glynn Isaac first applied the term “muddle in the middle” to a poorly understood period in the Middle Pleistocene human fossil record. This study uses the nasopharyngeal boundaries as a source of traits that may inform this unclear period of human evolution. The nasopharynx lies at the nexus of several vital physiological systems, yet relatively little is known about its importance in human evolution. We analyzed a geographically diverse contemporary Homo sapiens growth series (n = 180 adults, 237 nonadults), Homo neanderthalensis (La Chapelle aux Saints 1, La Ferrassie 1, Forbes Quarry 1, Monte Circeo 1, and Saccopastore 1), mid‐Pleistocene Homo (Atapuerca 5, Kabwe 1, Petralona 1, and Steinheim 1), and two Homo erectus sensu lato (KNM‐ER 3733 and Sangiran 17). Methods include traditional (Analysis 1) and 3D geometric morphometric analysis (Analysis 2). H. erectus exhibited tall, narrow nasopharyngeal shape, a robust, ancestral morphology. Kabwe 1 and Petralona 1 plotted among H. sapiens in Analysis 2, exhibiting relatively shorter and vertical cartilaginous Eustachian tubes and vertical medial pterygoid plates. Atapuerca 5 and Steinheim 1 exhibited horizontal vomeral orientation similar to H. neanderthalensis, indicating greater relative soft palate length and anteroposterior nasopharynx expansion. They may exhibit synapomorphies with H. neanderthalensis, supporting the accretionary hypothesis. Species‐level differences were found among H. sapiens and H. neanderthalensis, including relatively longer dilator tubae muscles and extreme facial airorhynchy among Neanderthals. Furthermore, H. neanderthalensis were autapomorphic in exhibiting horizontal pterygoid plate orientation similar to human infants, suggesting that they may have had inferiorly low placement of the torus tubarius and Eustachian tube orifice on the lateral nasopharyngeal wall in life. This study supports use of osseous nasopharyngeal boundaries both for morphological characters and understanding evolution of otitis media susceptibility in living humans.
... Development of the metacarpus in utero and after birth has only been extensively studied in humans (Scheuer et al., 2000), but the general developmental trajectory is assumed to be similar in African apes (Bolter & Zihlman, 2003;Kerley, 1966). A single primary ossification centre for each of the metacarpals 2-5 develops in utero and is located distally (Rolian, 2016). ...
The trabecular bone morphology of adult extant primates has been shown to reflect mechanical loading related to locomotion. However, ontogenetic studies of humans and other mammals suggest an adaptive lag between trabecular bone response and current mechanical loading patterns that could result in adult trabecular bone morphology reflecting juvenile behaviours. This study investigates ontogenetic changes in the trabecular bone structure of the third metacarpal of mountain gorillas (Gorilla beringei beringei; n = 26) and western lowland gorillas (Gorilla gorilla gorilla; n = 26) and its relationship to expected changes in locomotor loading patterns. Results show that trabecular bone reflects predicted mechanical loading throughout ontogeny. Bone volume fraction, trabecular thickness and trabecular number are low at birth and increase with age, although degree of anisotropy remains relatively stable throughout ontogeny. A high concentration of bone volume fraction can be observed in the distopalmar region of the third metacarpal epiphysis in early ontogeny, consistent with the high frequency of climbing, suspensory and other grasping behaviours in young gorillas. High trabecular bone concentration increases dorsally in the epiphysis during the juvenile period as terrestrial knuckle‐walking becomes the primary form of locomotion. However, fusion of the epiphysis does not take place until 10–11 years of age, and overall trabecular structure does not fully reflect the adult pattern until 12 years of age, indicating a lag between adult‐like behaviours and adult‐like trabecular morphology. We found minimal differences in trabecular ontogeny between mountain and western lowland gorillas, despite presumed variation in the frequencies of arboreal locomotor behaviours. Altogether, ontogenetic changes in Gorilla metacarpal trabecular structure reflect overall genus‐level changes in locomotor behaviours throughout development, but with some ontogenetic lag that should be considered when drawing functional conclusions from bone structure in extant or fossil adolescent specimens. This study investigates the ontogenetic changes in trabecular structure in western lowland and mountain gorilla third metacarpals and how these changes may reflect locomotor behaviour throughout development. We found that metacarpal trabecular structure reflects a higher frequency of grasping in early ontogeny and a shift to predominant knuckle walking locomotion in later ontogeny, but with an 'adaptive lag' between adult‐like behaviour and adult‐like trabecular structure that should be considered when analysing juvenile or young adult fossil specimens.
... The study species in this report are smaller bodied than early hominins. Adult male vervets average only 5.8 kg (Bolter and Zihlman, 2003), while early Homo was likely similar to the size of australopiths (estimated mean body mass from Grabowski et al., 2015: Australopithecus afarensis: 39.1 kg; Australopithecus africanus: 30.5 kg). Body size no doubt alters the perception of risk, real risk, and the ability to mount retaliatory action against predators. ...
The spatial behavior of primates is shaped by many factors including predation risk, the distribution of food sources, and access to water. In fire-prone settings, burning is a catalyst of change, altering the distribution of both plants and animals. Recent research has shown that primates alter their behavior in response to this change. Here, we study primates' perceived threat of predation in fire-modified landscapes. We focus on the predator-related behaviors of vervet monkeys (Chlorocebus pygerythrus) after controlled burning events. We compare the occurrence of vigilance and predator-deterrent behaviors, including alarm calls, scanning, and flight across different habitats and burn conditions to test the hypothesis that subjects exhibit fewer predator-specific vigilance and predator-deterrent behaviors in burned areas. The results demonstrate that predator-related behaviors occur less often in burned habitats, suggesting that predators are less common in these areas. These results provide foundations for examining hypotheses about the use of fire-altered landscapes among extinct hominins. We set these data in the context of increasing aridity, changes in burning regimes, and the emergence of pyrophilia in the human lineage.
... Based on dental eruption pattern, animals estimated to be below 11 months old were classified as infants, those 12-37 months old were considered subadults, while all animals whose teeth were fully erupted (>38 months) were classified as adults. 50 in Mombasa were positive for SIV. Amongst NHPs' age groups, infection was higher in adults (27/72, 38%) followed by subadults (9/36, 25%) and infants (3/16, 19%). ...
Background:
Simian immunodeficiency virus (SIV) naturally infects African non-human primates (NHPs) and poses a threat of transmission to humans through hunting and consumption of monkeys as bushmeat. This study investigated the as of yet unknown molecular diversity of SIV in free-ranging Chlorocebus species (African green monkeys-AGMs) and Papio anubis (olive baboons) within Mombasa, Kisumu and Naivasha urban centres in Kenya.
Methods:
We collected blood samples from 124 AGMs and 65 olive baboons in situ, and detected SIV by high-resolution melting analysis and sequencing of PCR products.
Results:
Simian immunodeficiency virus prevalence was 32% in AGMs and 3% in baboons. High-resolution melting (HRM) analysis demonstrated distinct melt profiles illustrating virus diversity confirmed by phylogenetic analysis.
Conclusions:
There is persistent evolutionary diversification of SIVagm strains in its natural host, AGMs and cross-species infection to olive baboons is occurring. Further study is required to establish pathogenesis of the diverse SIVagm variants and baboon immunological responses.
... Based on dental eruption pattern, animals estimated to be below 11 months old were classified as infants, those 12-37 months old were considered subadults, while all animals whose teeth were fully erupted (>38 months) were classified as adults. 50 in Mombasa were positive for SIV. Amongst NHPs' age groups, infection was higher in adults (27/72, 38%) followed by subadults (9/36, 25%) and infants (3/16, 19%). ...
Background
Simian immunodeficiency virus (SIV) naturally infects African non‐human primates (NHPs) and poses a threat of transmission to humans through hunting and consumption of monkeys as bushmeat. This study investigated the as of yet unknown molecular diversity of SIV in free‐ranging Chlorocebus species (African green monkeys—AGMs) and Papio anubis (olive baboons) within Mombasa, Kisumu and Naivasha urban centres in Kenya.
Methods
We collected blood samples from 124 AGMs and 65 olive baboons in situ, and detected SIV by high‐resolution melting analysis and sequencing of PCR products.
Results
Simian immunodeficiency virus prevalence was 32% in AGMs and 3% in baboons. High‐resolution melting (HRM) analysis demonstrated distinct melt profiles illustrating virus diversity confirmed by phylogenetic analysis.
Conclusions
There is persistent evolutionary diversification of SIVagm strains in its natural host, AGMs and cross‐species infection to olive baboons is occurring. Further study is required to establish pathogenesis of the diverse SIVagm variants and baboon immunological responses.
... Plasma nicotine concentrations were determined by HPLC. Body weight information was not provided for this study, and an average body weight of 6 kg for the green monkeys (Vervet monkeys, Cercopithecus aethiops) (Bolter and Zihlman, 2003;Lang, 2006) was used for model simulation. ...
The widespread use and high abuse liability of tobacco products has received considerable public health attention, in particular for youth, who are vulnerable to nicotine addiction. In this study, adult and adolescent squirrel monkeys were used to evaluate age-related metabolism and pharmacokinetics of nicotine after intravenous administration. A physiologically-based pharmacokinetic (PBPK) model was created to characterize the pharmacokinetic behaviors of nicotine and its metabolites, cotinine, trans-3'-hydroxycotinine (3'-OH cotinine), and trans-3'-hydroxycotinine glucuronide (3'-OH cotinine glucuronide) for both adult and adolescent squirrel monkeys. The PBPK nicotine model was first calibrated for adult squirrel monkeys utilizing in vitro nicotine metabolic data, plasma concentration-time profiles and cumulative urinary excretion data for nicotine and metabolites. Further model refinement was conducted when the calibrated adult model was scaled to the adolescents, because adolescents appeared to clear nicotine and cotinine more rapidly relative to adults. More specifically, the resultant model parameters representing systemic clearance of nicotine and cotinine for adolescent monkeys were approximately two- to three-fold of the adult values on a per body weight basis. The nonhuman primate PBPK model in general captured experimental observations that were used for both model calibration and evaluation, with acceptable performance metrics for precision and bias. The model also identified differences in nicotine pharmacokinetics between adolescent and adult nonhuman primates which might also be present in humans.
... By this definition, adulthood is reached upon eruption of M 3 . These growth stages have been shown to correspond with major developmental changes in cranial shape (Hellman, 1927;Ashton, 1957;Laitman et al., 1979;Bolter and Zihlman, 2003;Pagano et al., 2017). ...
Neanderthals are among the best studied and yet most enigmatic fossil human groups with aspects of their anatomy and functional morphology remaining poorly understood. We present the first anatomical reconstruction of the Neanderthal cartilaginous Eustachian tube (CET), a vital component of the upper respiratory tract and nexus for the middle ear and postnasal airway. The Eustachian (auditory, pharyngotympanic) tube, comprised of a bony and cartilaginous (CET) portion, is integral to normal physiological functions such as middle ear aeration and pressure equilibration. Findings indicate that Neanderthal tubal morphology may have predisposed them to high rates of middle ear disease (otitis media [OM]). In living humans, mechanical CET dysfunction underlies OM in infants and young children, with sequelae including hearing loss, meningitis, and pneumonia. Despite proven linkage of CET malfunction with OM, the role of CET morphology in Neanderthal health and disease remains unstudied. We reconstructed Neanderthal CET morphology, comparing their crania to a modern human growth series. Methods included geometric morphometrics and univariate measures among Procrustes‐fitted coordinates. Results showed Neanderthal adults exhibiting primitively tall and narrow nasopharynges with infant‐like horizontal CET and choanal orientation. As horizontal CET orientation is associated with increased OM incidence in infants and children until around age six, its appearance in Neanderthal adults strongly indicates persistence of high OM susceptibility at this time. This could have compromised fitness and disease load relative to sympatric modern humans, affecting Neanderthals' ability to compete within their ecological niche, and potentially contributing to their rapid extinction. Anat Rec, 302:2109–2125, 2019. © 2019 American Association for Anatomy
... Significant hard-tissue changes are known to occur within the primate craniofacial region during development. Muscle attachment sites are spatially reconfigured, the rostrum becomes increasingly prognathic, and deciduous dental elements are replaced by their permanent coun- terparts, extending the postcanine dental row (Bolter and Zihlman, 2006;Cochard, 1985;Collard and O'Higgins, 2001;Dechow and Carlson, 1990;O'Higgins & Jones, 1998;Ravosa, 1991;Richtsmeier, Cheverud, Danahey, Corner and Lele, 1993;Singleton, 2015). Collec- tively these changes serve to alter the biomechanical relationship between the muscles of mastication, the temporomandibular joint (TMJ), and the dentition (Hylander, 1985;Ravosa, 1996). ...
Objectives
Changes to soft‐ and hard‐tissue components of the masticatory complex during development can impact functional performance by altering muscle excursion potential, maximum muscle forces, and the efficiency of force transfer to specific bitepoints. Within Macaca fascicularis, older individuals exploit larger, more mechanically resistant food items and more frequently utilize wide‐gape jaw postures. We therefore predict that key architectural and biomechanical variables will scale during ontogeny to maximize bite force and gape potential within older, larger‐bodied individuals.
Materials and methods
We analyzed 26 specimens of M. fascicularis, representing a full developmental spectrum. The temporalis, superficial masseter, and deep masseter were dissected to determine muscle mass, fiber length, and physiologic cross‐sectional area (PCSA). Lever‐arm lengths were also measured for each muscle, alongside the height of the temporomandibular joint (TMJ) and basicranial length. These variables were scaled against two biomechanical variables (jaw length and condyle‐molar length) to determine relative developmental changes within these parameters.
Results
During ontogeny, muscle mass, fiber length, and PCSA scaled with positive allometry relative to jaw length and condyle‐molar length within all muscles. TMJ height also scaled with positive allometry, while muscle lever arms scaled with isometry relative to jaw length and with positive allometry (temporalis) or isometry (superficial and deep masseter) relative to condyle‐molar length.
Conclusion
Larger individuals demonstrate adaptations during development towards maximizing gape potential and bite force potential at both an anterior and posterior bitepoint. These data provide anatomical evidence to support field observations of dietary and behavioral differences between juvenile and adult M. fascicularis.
