Callum F Ro
Biographic Data
| ID | 625235 |
|---|---|
| NAME | Callum F Ro |
| GIVEN NAMES | Callum F |
| FAMILY NAME | Ro |
| SIGNATURE | RO C F |
| AFFILIATIONS | University of Chicago |
| ORCID | 0000-0001-7764-761X |
| VERIFIED | Yes |
| TOTAL WORKS | 60 |
| TOTAL CITATIONS | 606 |
| AUTHOR COUNT | 60 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1987 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 15 |
Primate Swallowing Is Powered by Both Rotation and Contraction of Suprahyoid Muscles
Biomechanics and Evolution of the Primate Tongue
Primate tongue morphology and function are critical to understanding the evolution of feeding, swallowing, and vocalization. In this paper, we examine the primate tongue as a muscular hydrostat with regionally specialized neuromuscular compartments. We integrate anatomical, kinematic, and biomechanical modeling approaches to analyze how muscle architecture and fiber orientation drive complex tongue deformations during functional behaviors. We eva…
Jaw-muscle fiber architecture and skull form facilitate relatively wide jaw gapes in male cercopithecoid monkeys
Morphological disparity and evolutionary transformations in the primate hyoid apparatus
The dental microwear of hard‐object feeding in laboratory Sapajus apella and its implications for dental microwear formation
OBJECTIVES: This study seeks to determine if (a) consumption of hard food items or a mixture of food items leads to the formation of premolar or molar microwear in laboratory capuchin monkeys (Sapajus apella) in one feeding session and (b) rates of microwear formation are associated with the number of food items consumed. MATERIALS AND METHODS: Five adult male capuchins were used in two experiments, one where they were fed unshelled Brazil nuts, …
Jaw kinematics and mandibular morphology in humans
Biomechanics of the mandible of Macaca mulatta during the power stroke of mastication: Loading, deformation, and strain regimes and the impact of food type
Mandible morphology has yet to yield definitive information on primate diet, probably because of poor understanding of mandibular loading and strain regimes, and overreliance on simple beam models of mandibular mechanics. We used a finite element model of a macaque mandible to test hypotheses about mandibular loading and strain regimes and relate variation in muscle activity during chewing on different foods to variation in strain regimes. The ba…
Taking a big bite: Working together to better understand the evolution of feeding in primates
The study of adaptation requires the integration of an array of different types of data. A single individual can find such integration daunting, if not impossible. In an effort to clarify the role of diet in the evolution of the primate craniofacial and dental apparatus, we assembled a team of researchers that have various types and degrees of expertise. This interaction has provided a range of insights for all contributors, and this has helped t…
Scaling of rotational inertia of primate mandibles
In vivo bone strain in the mandibular corpus of Sapajus during a range of oral food processing behaviors
Substrate Diameter and Orientation in the Context of Food Type in the Gray Mouse Lemur, Microcebus murinus: Implications for the Origins of Grasping in Primates
Jaw‐muscle force and excursion scale with negative allometry in platyrrhine primates
Objectives Platyrrhines span two orders of magnitude in body size and are characterized by diverse feeding behaviors and diets. While size plays an important role in primate feeding behavior and masticatory apparatus morphology, we know little about size‐correlated changes in the force‐generating (physiologic cross‐sectional area; PCSA) and excursion/stretch (fiber length; L f ) capabilities of the jaw‐closing muscles in platyrrhines. Methods We …
What does feeding system morphology tell us about feeding
Feeding is the set of behaviors whereby organisms acquire and process the energy required for survival and reproduction. Thus, feeding system morphology is presumably subject to selection to maintain or improve feeding performance. Relationships among feeding system morphology, feeding behavior, and diet not only explain the morphological diversity of extant primates, but can also be used to reconstruct feeding behavior and diet in fossil taxa. D…
Complexity, Modularity, and Integration in the Human Head. The Evolution of the Human Head
Viewpoints: Diet and dietary adaptations in early hominins: The hard food perspective
Recent biomechanical analyses examining the feeding adaptations of early hominins have yielded results consistent with the hypothesis that hard foods exerted a selection pressure that influenced the evolution of australopith morphology. However, this hypothesis appears inconsistent with recent reconstructions of early hominin diet based on dental microwear and stable isotopes. Thus, it is likely that either the diets of some australopiths include…
Anthropoid Origins: New Visions
Innovative Approaches to the Relationship Between Diet and Mandibular Morphology in Primates
Fossil papio cranium from !Ncumtsa (Koanaka) Hills, western Ngamiland, Botswana
Three fossils, a cranium of Papio , a cercopithecid frontal bone, and a mandible of juvenile Papio , have been recovered from cave deposits in the !Ncumtsa (Koanaka) Hills of western Ngamiland, Botswana. These specimens are significant because well‐preserved crania of Papio are extremely rare in the fossil record outside of South Africa and because this is the first report of fossil primate cranial remains from Botswana. Thermoluminescence dating…
Microwear, mechanics and the feeding adaptations of Australopithecus africanus
A finite element analysis of masticatory stress hypotheses
Understanding how the skull transmits and dissipates forces during feeding provides insights into the selective pressures that may have driven the evolution of primate skull morphology. Traditionally, researchers have interpreted masticatory biomechanics in terms of simple global loading regimes applied to simple shapes (i.e., bending in sagittal and frontal planes, dorsoventral shear, and torsion of beams and cylinders). This study uses finite e…
Darwinius masillae is a strepsirrhine—a reply to Franzen et al. (2009)
Effects of brain and facial size on basicranial form in human and primate evolution
The feeding biomechanics and dietary ecology of Australopithecus africanus
The African Plio-Pleistocene hominins known as australopiths evolved a distinctive craniofacial morphology that traditionally has been viewed as a dietary adaptation for feeding on either small, hard objects or on large volumes of food. A historically influential interpretation of this morphology hypothesizes that loads applied to the premolars during feeding had a profound influence on the evolution of australopith craniofacial form. Here, we te…
Scaling of chew cycle duration in primates
The biomechanical determinants of the scaling of chew cycle duration are important components of models of primate feeding systems at all levels, from the neuromechanical to the ecological. Chew cycle durations were estimated in 35 species of primates and analyzed in conjunction with data on morphological variables of the feeding system estimating moment of inertia of the mandible and force production capacity of the chewing muscles. Data on scal…
Ecological consequences of scaling of chew cycle duration and daily feeding time in Primates
Basicranial flexion, relative brain size, and facial kyphosis in nonhuman primates
Numerous hypotheses explaining interspecific differences in the degree of basicranial flexion have been presented. Several authors have argued that an increase in relative brain size results in a spatial packing problem that is resolved by flexing the basicranium. Others attribute differences in the degree of basicranial flexion to different postural behaviors, suggesting that more orthograde animals require a ventrally flexed pre‐sella basicrani…
Viewpoints: Diet and dietary adaptations in early hominins: The hard food perspective
Recent biomechanical analyses examining the feeding adaptations of early hominins have yielded results consistent with the hypothesis that hard foods exerted a selection pressure that influenced the evolution of australopith morphology. However, this hypothesis appears inconsistent with recent reconstructions of early hominin diet based on dental microwear and stable isotopes. Thus, it is likely that either the diets of some australopiths include…
Phylogenetic analysis of anthropoid relationships
Basicranial flexion, relative brain size, and facial kyphosis in Homo sapiens and some fossil hominids
Comparative work among nonhominid primates has demonstrated that the basicranium becomes more flexed with increasing brain size relative to basicranial length and as the ‐upper and lower face become more ventrally deflected (Ross and Ravosa [1993] Am. J. Phys. Anthropol. 91: 305–324). In order to determine whether modern humans and fossil hominids follow these trends, the cranial base angle (measure of basicranial flexion), angle of facial kyphos…
Into the Light: The Origin of Anthropoidea
Anthropoidea is a clade of primates including Platyrrhini and Catarrhini. Definitive fossil anthropoids include the early Oligocene Propliopithecidae and the late Eocene-early Oligocene Parapithecidae and Oligopithecidae. Middle Eocene Eosimiidae are probable fossil anthropoids from Asia. Relationships of anthropoids to other primates are debated, although parsimony argues for a tarsier-anthropoid clade (Haplorhini) arising within omomyiforms. Di…
Innovative Approaches to the Relationship Between Diet and Mandibular Morphology in Primates
Effects of brain and facial size on basicranial form in human and primate evolution
Allometric and functional influences on primate orbit orientation and the origins of the Anthropoidea
Evolution of activity patterns and chromatic vision in primates: Morphometrics, Genetics and Cladistics
In vivo function of the craniofacial haft: The interorbital “pillar”
The craniofacial haft resists forces generated in the face during feeding, but the importance of these forces for the form of the craniofacial haft remains to be determined. In vivo bone strain data were recorded from the medial orbital wall in an owl monkey ( Aotus ), rhesus macaques ( Macaca mulatta ), and a galago ( Otolemur ) during feeding. These data were used to determine whether: the interorbital region can be modeled as a simple beam und…
Curvilinear, geometric and phylogenetic modeling of basicranial flexion: Is It Adaptive, Is It Constrained
Ecological consequences of scaling of chew cycle duration and daily feeding time in Primates
Temporalis function in anthropoids and strepsirrhines: An EMG study
The major purpose of this study is to analyze anterior and posterior temporalis muscle force recruitment and firing patterns in various anthropoid and strepsirrhine primates. There are two specific goals for this project. First, we test the hypothesis that in addition to transversely directed muscle force, the evolution of symphyseal fusion in primates may also be linked to vertically directed balancing‐side muscle force during chewing (Hylander …
Muscular and osseous anatomy of the primate anterior temporal fossa and the functions of the postorbital septum
Many adaptive explanations for anthropoid origins incorporate hypotheses regarding the function of the postorbital septum. Two hypotheses are evaluated here: Cachel's ([1979b] Am. J. Phys. Anthropol. 50:1–18) hypothesis that the anthropoid postorbital septum evolved to augment muscle attachment area in the anterior temporal fossa and Cartmill's ([1980] in RL Ciochon and AB Chiarelli (eds.): Evolutionary Biology of the New World Monkeys and Contin…
Masticatory biomechanics and its relevance to early hominid phylogeny: An examination of palatal thickness using finite-element analysis
Scaling of chew cycle duration in primates
The biomechanical determinants of the scaling of chew cycle duration are important components of models of primate feeding systems at all levels, from the neuromechanical to the ecological. Chew cycle durations were estimated in 35 species of primates and analyzed in conjunction with data on morphological variables of the feeding system estimating moment of inertia of the mandible and force production capacity of the chewing muscles. Data on scal…
Evolution of eye size and shape in primates
In vivo bone strain in the mandibular corpus of Sapajus during a range of oral food processing behaviors
Microwear, mechanics and the feeding adaptations of Australopithecus africanus
Substrate Diameter and Orientation in the Context of Food Type in the Gray Mouse Lemur, Microcebus murinus: Implications for the Origins of Grasping in Primates
A finite element analysis of masticatory stress hypotheses
Understanding how the skull transmits and dissipates forces during feeding provides insights into the selective pressures that may have driven the evolution of primate skull morphology. Traditionally, researchers have interpreted masticatory biomechanics in terms of simple global loading regimes applied to simple shapes (i.e., bending in sagittal and frontal planes, dorsoventral shear, and torsion of beams and cylinders). This study uses finite e…
Jaw‐muscle force and excursion scale with negative allometry in platyrrhine primates
Objectives Platyrrhines span two orders of magnitude in body size and are characterized by diverse feeding behaviors and diets. While size plays an important role in primate feeding behavior and masticatory apparatus morphology, we know little about size‐correlated changes in the force‐generating (physiologic cross‐sectional area; PCSA) and excursion/stretch (fiber length; L f ) capabilities of the jaw‐closing muscles in platyrrhines. Methods We …
The petrosal of Omomys carteriand the evolution of the primate basicranium
The dental microwear of hard‐object feeding in laboratory Sapajus apella and its implications for dental microwear formation
OBJECTIVES: This study seeks to determine if (a) consumption of hard food items or a mixture of food items leads to the formation of premolar or molar microwear in laboratory capuchin monkeys (Sapajus apella) in one feeding session and (b) rates of microwear formation are associated with the number of food items consumed. MATERIALS AND METHODS: Five adult male capuchins were used in two experiments, one where they were fed unshelled Brazil nuts, …
Fossil papio cranium from !Ncumtsa (Koanaka) Hills, western Ngamiland, Botswana
Three fossils, a cranium of Papio , a cercopithecid frontal bone, and a mandible of juvenile Papio , have been recovered from cave deposits in the !Ncumtsa (Koanaka) Hills of western Ngamiland, Botswana. These specimens are significant because well‐preserved crania of Papio are extremely rare in the fossil record outside of South Africa and because this is the first report of fossil primate cranial remains from Botswana. Thermoluminescence dating…
A misuse of evolutionary models in archaeology: The Evolution of the Polynesian chiefdoms
Basicranial flexion, relative brain size, and facial kyphosis in nonhuman primates
Numerous hypotheses explaining interspecific differences in the degree of basicranial flexion have been presented. Several authors have argued that an increase in relative brain size results in a spatial packing problem that is resolved by flexing the basicranium. Others attribute differences in the degree of basicranial flexion to different postural behaviors, suggesting that more orthograde animals require a ventrally flexed pre‐sella basicrani…
The Craniofacial Evidence for Anthropoid and Tarsier Relationships
Craniodental allometry and heterochrony in two howler monkeys: Alouatta seniculus and A. palliata
Cranial dimensions were collected from growth series for two sexually dimorphic congeners: Alouatta seniculus , the red howler monkey, and Alouatta palliata , the mantled howler monkey. In both A. seniculus and A. palliata , ontogenetic series for males and females were compared to evaluate if sexual dimorphism in skull form results from the differential extension of common patterns of relative growth. Subsequently, growth series for both species…
Muscular and osseous anatomy of the primate anterior temporal fossa and the functions of the postorbital septum
Many adaptive explanations for anthropoid origins incorporate hypotheses regarding the function of the postorbital septum. Two hypotheses are evaluated here: Cachel's ([1979b] Am. J. Phys. Anthropol. 50:1–18) hypothesis that the anthropoid postorbital septum evolved to augment muscle attachment area in the anterior temporal fossa and Cartmill's ([1980] in RL Ciochon and AB Chiarelli (eds.): Evolutionary Biology of the New World Monkeys and Contin…
Basicranial flexion, relative brain size, and facial kyphosis in Homo sapiens and some fossil hominids
Comparative work among nonhominid primates has demonstrated that the basicranium becomes more flexed with increasing brain size relative to basicranial length and as the ‐upper and lower face become more ventrally deflected (Ross and Ravosa [1993] Am. J. Phys. Anthropol. 91: 305–324). In order to determine whether modern humans and fossil hominids follow these trends, the cranial base angle (measure of basicranial flexion), angle of facial kyphos…
Allometric and functional influences on primate orbit orientation and the origins of the Anthropoidea
Primate paleontology
Adaptive explanation for the origins of the anthropoidea (primates)
A new explanation for the origin of the primate suborder Anthropoidea is presented. Functional analyses of the “forward”-facing orbits, postorbital septum and retinal fovea are used to reconstruct the morphological and ecological contexts in which these features are most likely to have evolved. The postorbital septum is argued to have evolved as an adaptation to protect the orbital contents from encroaching fibers of anterior temporalis. This enc…
Adaptive explanation for the origins of the anthropoidea (primates)
A new explanation for the origin of the primate suborder Anthropoidea is presented. Functional analyses of the "forward"-facing orbits, postorbital septum and retinal fovea are used to reconstruct the morphological and ecological contexts in which these features are most likely to have evolved. The postorbital septum is argued to have evolved as an adaptation to protect the orbital contents from encroaching fibers of anterior temporalis. This enc…
Forthcoming inAmerican Journal of Primatology
In vivo and in vitro bone strain in the owl monkey circumorbital region and the function of the postorbital septum
Anthropoids and tarsiers are the only vertebrates possessing a postorbital septum. This septum, formed by the frontal, alisphenoid, and zygomatic bones, separates the orbital contents from the temporal muscles. Three hypotheses suggest that the postorbital septum evolved to resist stresses acting on the skull during mastication or incision. The facial-torsion hypothesis posits that the septum resists twisting of the face about a rostrocaudal axis…
Anthropoid Origins
Recent fossil discoveries have greatly increased our knowledge of the morphology and diversity of early Anthropoidea, the suborder to which humans belong. Phylogenetic analysis of Recent and fossil taxa supports the hypotheses that a haplorhine-strepsirrhine dichotomy existed at least at the time of the earliest record of fossil primates (earliest Eocene) and that eosimiids (middle Eocene, China) are primitive anthropoids. Functional analysis sug…
Mandibular corpus strain in primates: Further evidence for a functional link between symphyseal fusion and jaw‐adductor muscle force
Previous work indicates that compared to adult thick-tailed galagos, adult long-tailed macaques have much more bone strain on the balancing-side mandibular corpus during unilateral isometric molar biting (Hylander [1979a] J. Morphol. 159:253–296). Recently we have confirmed in these same two species the presence of similar differences in bone-strain patterns during forceful mastication. Moreover, we have also recorded mandibular bone strain patte…
Mandibular corpus strain in primates: Further evidence for a functional link between symphyseal fusion and jaw-adductor muscle force
Previous work indicates that compared to adult thick-tailed galagos, adult long-tailed macaques have much more bone strain on the balancing-side mandibular corpus during unilateral isometric molar biting (Hylander [1979a] J. Morphol. 159:253-296). Recently we have confirmed in these same two species the presence of similar differences in bone-strain patterns during forceful mastication. Moreover, we have also recorded mandibular bone strain patte…
Phylogenetic analysis of anthropoid relationships
Kinematic data on primate head and neck posture: Implications for the evolution of basicranial flexion and an evaluation of registration planes used in paleoanthropology
Kinematic data on primate head and neck posture were collected by filming 29 primate species during locomotion. These were used to test whether head and neck posture are significant influences on basicranial flexion and whether the Frankfurt plane can legitimately be employed in paleoanthropological studies. Three kinematic measurements were recorded as angles relative to the gravity vector, the inclination of the orbital plane, the inclination o…
How to Carry Out Functional Morphology
The primate cranial base: Ontogeny, function, and integration
Understanding the complexities of cranial base development, function, and architecture is important for testing hypotheses about many aspects of craniofacial variation and evolution. We summarize key aspects of cranial base growth and development in primates that are useful for formulating and testing hypotheses about the roles of the chondrocranium and basicranium in cranial growth, integration, and function in primate and human evolution. We re…
The primate cranial base: Ontogeny, function, and integration
Understanding the complexities of cranial base development, function, and architecture is important for testing hypotheses about many aspects of craniofacial variation and evolution. We summarize key aspects of cranial base growth and development in primates that are useful for formulating and testing hypotheses about the roles of the chondrocranium and basicranium in cranial growth, integration, and function in primate and human evolution. We re…
Electromyography of the anterior temporalis and masseter muscles of owl monkeys (Aotus trivirgatus) and the function of the postorbital septum
Anthropoids and tarsiers are distinguished from all other vertebrates by the possession of a postorbital septum, which is formed by the frontal, alisphenoid, and zygomatic bones. Cartmill [(1980) In: Evolutionary Biology of the New World Monkeys and Continental Drift. New York: Plenum, p 243–274] suggested that the postorbital septum evolved in the stem lineage of tarsiers and anthropoids to insulate the eye from movements arising in the temporal…
Electromyography of the anterior temporalis and masseter muscles of owl monkeys (Aotus trivirgatus) and the function of the postorbital septum
Anthropoids and tarsiers are distinguished from all other vertebrates by the possession of a postorbital septum, which is formed by the frontal, alisphenoid, and zygomatic bones. Cartmill [(1980) In: Evolutionary Biology of the New World Monkeys and Continental Drift. New York: Plenum, p 243-274] suggested that the postorbital septum evolved in the stem lineage of tarsiers and anthropoids to insulate the eye from movements arising in the temporal…
Biomechanics of mammalian feeding and primate evolution
The petrosal of Omomys carteriand the evolution of the primate basicranium
Symphyseal fusion and jaw-adductor muscle force: An EMG study
The purpose of this study is to test various hypotheses about balancing-side jaw muscle recruitment patterns during mastication, with a major focus on testing the hypothesis that symphyseal fusion in anthropoids is due mainly to vertically- and/or transversely-directed jaw muscle forces. Furthermore, as the balancing-side deep masseter has been shown to play an important role in wishboning of the macaque mandibular symphysis, we test the hypothes…
Biology (51 works) · Primate Behavior and Ecology (48 works) · Anatomy (30 works) · Primate (29 works) · Evolutionary biology (25 works) · Paleontology (24 works) · Anatomy (22 works) · Medicine (20 works) · Zoology (18 works) · Neuroscience (17 works)