Susan G Larson
Biographic Data
| ID | 3636411 |
|---|---|
| NAME | Susan G Larson |
| GIVEN NAMES | Susan G |
| FAMILY NAME | Larson |
| SIGNATURE | LARSON S G |
| AFFILIATIONS | Smithsonian Institution |
| VERIFIED | No |
| TOTAL WORKS | 36 |
| TOTAL CITATIONS | 380 |
| AUTHOR COUNT | 36 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1978 |
| LATEST PUBLICATION YEAR | 2015 |
| H-INDEX | 12 |
Electromyography of crural and pedal muscles in tufted capuchin monkeys ( Sapajus apella ): Implications for hallucal grasping behavior and first metatarsal morphology in euprimates
A hypertrophied peroneal process of the hallucal metatarsal, as seen in prosimians, has been linked to a powerful hallucal grasp via the contraction of the peroneus longus (PL) muscle causing adduction of the big toe. Electromyography (EMG) studies of lemurs and lorises, however, have concluded that PL is not substantially recruited during small branch locomotion when powerful hallucal grasping is needed most, and have suggested that there is no …
Three-dimensional kinematics of the pelvis and hind limbs in chimpanzee (Pan troglodytes) and human bipedal walking
Rotator cuff muscle size and the interpretation of scapular shape in primates
Brief communication: Cineradiographic analysis of the chimpanzee ( Pan troglodytes ) talonavicular and calcaneocuboid joints
During terrestrial locomotion, chimpanzees exhibit dorsiflexion of the midfoot between midstance and toe‐off of stance phase, a phenomenon that has been called the “midtarsal break.” This motion is generally absent during human bipedalism, and in chimpanzees is associated with more mobile foot joints than in humans. However, the contribution of individual foot joints to overall foot mobility in chimpanzees is poorly understood, particularly on th…
Shoulder Morphology in Early Hominin Evolution
Rotator cuff muscle function and its relation to scapular morphology in apes
Weight support distribution during quadrupedal walking in Ateles and Cebus
While it is well known that primate quadrupeds are distinctive in supporting more body weight on their hind limbs than their forelimbs, it has been unclear how this support asymmetry comes about. The simple explanation of a difference in body center of mass (COM) position is not supported by empirical data, leaving two less intuitive proposals. The first involves the position of the hands and feet relative to the COM, and has recently received su…
Evolution of the Hominin Shoulder: Early Homo
Hip extensor EMG and forelimb/hind limb weight support asymmetry in primate quadrupeds
Higher weight support on the hind limb than forelimb is among the distinctive characteristics of primate quadrupeds. Although often assumed to be due to a more posteriorly positioned whole body center of mass, there are little data to support such a difference. Reynolds (1985. Am J Phys Anthropol 67:335–349) notes that the distribution of forces on the limbs can also be influenced by average limb posture, but suggests that this effect is too smal…
The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution
Whether the Late Pleistocene hominin fossils from Flores, Indonesia, represent a new species, Homo floresiensis, or pathological modern humans has been debated. Analysis of three wrist bones from the holotype specimen (LB1) shows that it retains wrist morphology that is primitive for the African ape-human clade. In contrast, Neandertals and modern humans share derived wrist morphology that forms during embryogenesis, which diminishes the probabil…
Evolutionary transformation of the hominin shoulder
The definition of humeral torsion: A comment on Rhodes (2006)
Homo floresiensis and the evolution of the hominin shoulder
Maintenance of above-branch balance during primate arboreal quadrupedalism: Coordinated use of forearm rotators and tail motion
Animals that live and travel in trees display a variety of morphological and behavioral adaptations to help them maintain balance on narrow flexible supports. Among these adaptations are long tails that can be used as counterweights, and freely mobile limbs in order to reach discontinuous supports. Here we describe two additional ways in which these features can contribute to balance during arboreal locomotion. Electromyographic (EMG) recordings …
Compliant walking in primates: Elbow and knee yield in primates compared to other mammals
It has been suggested that primates utilize a compliant gait to help reduce peak locomotor stresses on their limbs (Schmitt [ 1994 ] J. Hum. Evol. 26: 441–458; Schmitt [ 1998 ] Primate Locomotion , p. 175–200; Schmitt [ 1999 ] J. Zool. Lond. 248: 149–160). However, the components of such a gait, i.e., increased step length, prolonged contact time, and substantial limb yield, have only been documented on a handful of primate species. In order to e…
Mechanisms of force and power production in unsteady ricochetal brachiation
Brachiators travel by swinging beneath handholds, and it is not obvious how these animals manage to accelerate and decelerate in a horizontal direction, especially when moving rapidly. Most previous analyses focused on brachiation in highly constrained laboratory conditions that induced steady‐state locomotion. Emerging understanding of brachiation suggests that much of gibbon locomotory behavior and morphology must be considered within the conte…
Forearm rotation and the “origin of the hominoid lifestyle”: Response to Sarmiento
Patterns of strain in the macaque tibia during functional activity
Patterns of strain in the macaque tibia during functional activity
The strain environment of the tibial midshaft of two female macaques was evaluated through in vivo bone strain experiments using three rosette gauges around the circumference of the bones. Strains were collected for a total of 123 walking and galloping steps as well as several climbing cycles. Principal strains and the angle of the maximum (tensile) principal strain with the long axis of the bone were calculated for each gauge site. In addition, …
Telemetered electromyography of the supinators and pronators of the forearm in gibbons and chimpanzees: Implications for the fundamental positional adaptation of hominoids
Extant apes are similar to one another, and different from monkeys, in features granting them greater range of forearm rotation and greater size of the muscles that produce this motion. Although these traits may have been independently acquired by the various apes, the possibility arises that such features reflect adaptation to the stem behavior of the hominoid lineage. Anticipating that knowledge of forearm rotatory muscle recruitment during bra…
Uniqueness of primate forelimb posture during quadrupedal locomotion
Among the characteristics that are thought to set primate quadrupedal locomotion apart from that of nonprimate mammals are a more protracted limb posture and larger limb angular excursion. However, kinematic aspects of primate or nonprimate quadrupedal locomotion have been documented in only a handful of species, and more widely for the hind than the forelimb. This study presents data on arm (humerus) and forelimb posture during walking for 102 s…
Uniqueness of primate forelimb posture during quadrupedal locomotion
Among the characteristics that are thought to set primate quadrupedal locomotion apart from that of nonprimate mammals are a more protracted limb posture and larger limb angular excursion. However, kinematic aspects of primate or nonprimate quadrupedal locomotion have been documented in only a handful of species, and more widely for the hind than the forelimb. This study presents data on arm (humerus) and forelimb posture during walking for 102 s…
Parallel evolution in the hominoid trunk and forelimb
The evolutionary history of the living hominoids has remained elusive despite years of exploration and the discovery of numerous Miocene fossil ape species. Part of the difficulty can be attributed to the changing nature of our views about the course of hominoid evolution. In the 1950s and 1960s, individual Miocene taxa were commonly viewed as the direct ancestors of specific living ape species, suggesting an early divergence of the modern lineag…
Patterns of strain in the macaque ulna during functional activity
In vivo bone strain experiments were performed on the ulnae of three female rhesus macaques to test how the bone deforms during locomotion. The null hypothesis was that, in an animal moving its limbs predominantly in sagittal planes, the ulna experiences anteroposterior bending. Three rosette strain gauges were attached around the circumference of the bone slightly distal to midshaft. They permit a complete characterization of the ulna's loading …
New characters for the functional interpretation of primate scapulae and proximal humeri
The study of muscle function in nonhuman primates through the technique of electromyography (EMG) has facilitated the identification of specific functional roles for muscles in particular behaviors. This has led to a more complete understanding of the biomechanics of certain regions of the musculoskeletal system, and should facilitate our ability to identify morphological features useful in the functional interpretation of fossil material. The cu…
Homo floresiensis and the evolution of the hominin shoulder
Heel contact as a function of substrate type and speed in primates
In this report we provide detailed data on the patterns and frequency of heel contact with terrestrial and arboreal supports in primates. These data can help resolve the question of whether African apes and humans are uniquely “plantigrade” (Gebo [1992] Am. J. Phys. Anthropol. 89 :29–58; Gebo [1993a] Am. J. Phys. Anthropol. 97 :382–385; Gebo [1993b] Postcranial Adaptation in Nonhuman Primates ), or if plantigrady is common in other primates (Meld…
Subscapularis function in gibbons and chimpanzees: Implications for interpretation of humeral head torsion in hominoids
Chimpanzees and gibbons, along with other hominoids, share a number of features in the morphology of their shoulders that have generally been associated with use of the upper limb in overhead postural and locomotor activities. These include the position and shape of the scapula, as well as the morphology of the proximal end of the humerus. Results of an electromyographic (EMG) analysis of shoulder muscle activity patterns indicate that these two …
New characters for the functional interpretation of primate scapulae and proximal humeri
The study of muscle function in nonhuman primates through the technique of electromyography (EMG) has facilitated the identification of specific functional roles for muscles in particular behaviors. This has led to a more complete understanding of the biomechanics of certain regions of the musculoskeletal system, and should facilitate our ability to identify morphological features useful in the functional interpretation of fossil material. The cu…
EMG of serratus anterior and trapezius in the chimpanzee: Scapular rotators revisited
The importance of arm‐raising has been a major consideration in the functional interpretation of differences in shoulder morphology among species of nonhuman primates. Among the characters that have been associated with enhancement of the arm‐raising mechanism in hominoid primates are the relative enlargement of cranial trapezius and caudal serratus anterior, as the main scapular rotators, as well as changes in scapular morphology associated with…
Role of supraspinatus in the quadrupedal locomotion of vervets ( Cercopithecus aethiops ): Implications for interpretation of humeral morphology
Various researchers have noted that terrestrial and arboreal monkeys often differ in the degree to which the greater tubercle of the humerus projects proximally beyond the profile of the humeral head. These differences have been associated with differing leverage requirements for supraspinatus during quadrupedal locomotion. Although Jolly ( The Baboon in Medical Research , Vol. II., pp. 23–50, 1967) suggested that a projecting tubercle can be rel…
Compliant walking in primates: Elbow and knee yield in primates compared to other mammals
It has been suggested that primates utilize a compliant gait to help reduce peak locomotor stresses on their limbs (Schmitt [ 1994 ] J. Hum. Evol. 26: 441–458; Schmitt [ 1998 ] Primate Locomotion , p. 175–200; Schmitt [ 1999 ] J. Zool. Lond. 248: 149–160). However, the components of such a gait, i.e., increased step length, prolonged contact time, and substantial limb yield, have only been documented on a handful of primate species. In order to e…
Three-dimensional kinematics of the pelvis and hind limbs in chimpanzee (Pan troglodytes) and human bipedal walking
Telemetered electromyography of the supinators and pronators of the forearm in gibbons and chimpanzees: Implications for the fundamental positional adaptation of hominoids
Extant apes are similar to one another, and different from monkeys, in features granting them greater range of forearm rotation and greater size of the muscles that produce this motion. Although these traits may have been independently acquired by the various apes, the possibility arises that such features reflect adaptation to the stem behavior of the hominoid lineage. Anticipating that knowledge of forearm rotatory muscle recruitment during bra…
Maintenance of above-branch balance during primate arboreal quadrupedalism: Coordinated use of forearm rotators and tail motion
Animals that live and travel in trees display a variety of morphological and behavioral adaptations to help them maintain balance on narrow flexible supports. Among these adaptations are long tails that can be used as counterweights, and freely mobile limbs in order to reach discontinuous supports. Here we describe two additional ways in which these features can contribute to balance during arboreal locomotion. Electromyographic (EMG) recordings …
Weight support distribution during quadrupedal walking in Ateles and Cebus
While it is well known that primate quadrupeds are distinctive in supporting more body weight on their hind limbs than their forelimbs, it has been unclear how this support asymmetry comes about. The simple explanation of a difference in body center of mass (COM) position is not supported by empirical data, leaving two less intuitive proposals. The first involves the position of the hands and feet relative to the COM, and has recently received su…
Brief communication: Cineradiographic analysis of the chimpanzee ( Pan troglodytes ) talonavicular and calcaneocuboid joints
During terrestrial locomotion, chimpanzees exhibit dorsiflexion of the midfoot between midstance and toe‐off of stance phase, a phenomenon that has been called the “midtarsal break.” This motion is generally absent during human bipedalism, and in chimpanzees is associated with more mobile foot joints than in humans. However, the contribution of individual foot joints to overall foot mobility in chimpanzees is poorly understood, particularly on th…
Hip extensor EMG and forelimb/hind limb weight support asymmetry in primate quadrupeds
Higher weight support on the hind limb than forelimb is among the distinctive characteristics of primate quadrupeds. Although often assumed to be due to a more posteriorly positioned whole body center of mass, there are little data to support such a difference. Reynolds (1985. Am J Phys Anthropol 67:335–349) notes that the distribution of forces on the limbs can also be influenced by average limb posture, but suggests that this effect is too smal…
Rotator cuff muscle function and its relation to scapular morphology in apes
Further evidence for the role of supraspinatus in quadrupedal monkeys
Differences in the degree of projection of the greater tubercle above the level of the humeral head in primate proximal humeri have been associated with differing leverage requirements for supraspinatus during arboreal vs. terrestrial quadrupedal locomotion. Since most workers have assumed that supraspinatus acts as a humeral protractor, interpretations of the variation in greater tubercle height have focused on the need for powerful vs. rapid hu…
Rotator cuff muscle size and the interpretation of scapular shape in primates
Mechanisms of force and power production in unsteady ricochetal brachiation
Brachiators travel by swinging beneath handholds, and it is not obvious how these animals manage to accelerate and decelerate in a horizontal direction, especially when moving rapidly. Most previous analyses focused on brachiation in highly constrained laboratory conditions that induced steady‐state locomotion. Emerging understanding of brachiation suggests that much of gibbon locomotory behavior and morphology must be considered within the conte…
EMG of the digastric muscle in gibbon and orangutan: Functional consequences of the loss of the anterior digastric in orangutans
Unlike all other primates, the digastric muscle of the orangutan lacks an anterior belly; the posterior belly, while present, inserts directly onto the mandible. To understand the functional consequences of this morphologic novelty, the EMG activity patterns of the digastric muscle and other potential mandibular depressors were studied in a gibbon and an orangutan. The results suggest a significant degree of functional differentiation between the…
Scaling of organ weights in Macaca arctoides
The allometric scaling of nine internal organs was examined for Macaca arctoides. Significant organ weight‐body weight regressions were obtained for heart, lungs, kidneys, pancreas, thyroid, liver, and testes. The spleen and adrenal glands exhibited strong variability and were only loosely correlated to body weight. Using allometry as a criterion of subtraction, observed sex differences in mean organ weights were seen to be primarily the result o…
The definition of humeral torsion: A comment on Rhodes (2006)
Electromyography of crural and pedal muscles in tufted capuchin monkeys ( Sapajus apella ): Implications for hallucal grasping behavior and first metatarsal morphology in euprimates
A hypertrophied peroneal process of the hallucal metatarsal, as seen in prosimians, has been linked to a powerful hallucal grasp via the contraction of the peroneus longus (PL) muscle causing adduction of the big toe. Electromyography (EMG) studies of lemurs and lorises, however, have concluded that PL is not substantially recruited during small branch locomotion when powerful hallucal grasping is needed most, and have suggested that there is no …
Scaling of organ weights in Macaca arctoides
The allometric scaling of nine internal organs was examined for Macaca arctoides. Significant organ weight‐body weight regressions were obtained for heart, lungs, kidneys, pancreas, thyroid, liver, and testes. The spleen and adrenal glands exhibited strong variability and were only loosely correlated to body weight. Using allometry as a criterion of subtraction, observed sex differences in mean organ weights were seen to be primarily the result o…
Ontogenetic and interspecific organ weight allometry in Old World monkeys
The importance of allometry as an analytic tool is well recognized in the literature of primate morphology. However, a number of recent studies have illustrated how interpretive difficulties can arise when researchers confound different types of allometric data. Such confusion is due less to carelessness than to uncertainty about how different types of allometry are related. The present study examines the relationship between two types—ontogeneti…
Organ Weight Scaling in Primates
EMG of scapulohumeral muscles in the chimpanzee during reaching and “arboreal” locomotion
Current views on the function of the deltoid and rotator cuff muscles emphasize their roles in arm‐raising as participants in a scapulohumeral force “couple.” The acceptance of such a mechanism is based primarily on a 1944 EMG study of human shoulder muscle action. More recently, it has been suggested that shoulder joint stabilization constitutes a second and equally important function of the cuff musculature, especially in nonhuman primates whic…
Subscapularis function in gibbons and chimpanzees: Implications for interpretation of humeral head torsion in hominoids
Chimpanzees and gibbons, along with other hominoids, share a number of features in the morphology of their shoulders that have generally been associated with use of the upper limb in overhead postural and locomotor activities. These include the position and shape of the scapula, as well as the morphology of the proximal end of the humerus. Results of an electromyographic (EMG) analysis of shoulder muscle activity patterns indicate that these two …
Primate Locomotion: Utilization and Control of Symmetrical Gaits
Infrastructures are material forms that allow for the possibility of exchange over space. They are the physical networks through which goods, ideas, waste, power, people, and finance are trafficked. In this article I trace the range of anthropological ...Read More
Role of supraspinatus in the quadrupedal locomotion of vervets ( Cercopithecus aethiops ): Implications for interpretation of humeral morphology
Various researchers have noted that terrestrial and arboreal monkeys often differ in the degree to which the greater tubercle of the humerus projects proximally beyond the profile of the humeral head. These differences have been associated with differing leverage requirements for supraspinatus during quadrupedal locomotion. Although Jolly ( The Baboon in Medical Research , Vol. II., pp. 23–50, 1967) suggested that a projecting tubercle can be rel…
EMG of serratus anterior and trapezius in the chimpanzee: Scapular rotators revisited
The importance of arm‐raising has been a major consideration in the functional interpretation of differences in shoulder morphology among species of nonhuman primates. Among the characters that have been associated with enhancement of the arm‐raising mechanism in hominoid primates are the relative enlargement of cranial trapezius and caudal serratus anterior, as the main scapular rotators, as well as changes in scapular morphology associated with…
Further evidence for the role of supraspinatus in quadrupedal monkeys
Differences in the degree of projection of the greater tubercle above the level of the humeral head in primate proximal humeri have been associated with differing leverage requirements for supraspinatus during arboreal vs. terrestrial quadrupedal locomotion. Since most workers have assumed that supraspinatus acts as a humeral protractor, interpretations of the variation in greater tubercle height have focused on the need for powerful vs. rapid hu…
EMG of the digastric muscle in gibbon and orangutan: Functional consequences of the loss of the anterior digastric in orangutans
Unlike all other primates, the digastric muscle of the orangutan lacks an anterior belly; the posterior belly, while present, inserts directly onto the mandible. To understand the functional consequences of this morphologic novelty, the EMG activity patterns of the digastric muscle and other potential mandibular depressors were studied in a gibbon and an orangutan. The results suggest a significant degree of functional differentiation between the…
New characters for the functional interpretation of primate scapulae and proximal humeri
The study of muscle function in nonhuman primates through the technique of electromyography (EMG) has facilitated the identification of specific functional roles for muscles in particular behaviors. This has led to a more complete understanding of the biomechanics of certain regions of the musculoskeletal system, and should facilitate our ability to identify morphological features useful in the functional interpretation of fossil material. The cu…
Heel contact as a function of substrate type and speed in primates
In this report we provide detailed data on the patterns and frequency of heel contact with terrestrial and arboreal supports in primates. These data can help resolve the question of whether African apes and humans are uniquely “plantigrade” (Gebo [1992] Am. J. Phys. Anthropol. 89 :29–58; Gebo [1993a] Am. J. Phys. Anthropol. 97 :382–385; Gebo [1993b] Postcranial Adaptation in Nonhuman Primates ), or if plantigrady is common in other primates (Meld…
Parallel evolution in the hominoid trunk and forelimb
The evolutionary history of the living hominoids has remained elusive despite years of exploration and the discovery of numerous Miocene fossil ape species. Part of the difficulty can be attributed to the changing nature of our views about the course of hominoid evolution. In the 1950s and 1960s, individual Miocene taxa were commonly viewed as the direct ancestors of specific living ape species, suggesting an early divergence of the modern lineag…
Patterns of strain in the macaque ulna during functional activity
In vivo bone strain experiments were performed on the ulnae of three female rhesus macaques to test how the bone deforms during locomotion. The null hypothesis was that, in an animal moving its limbs predominantly in sagittal planes, the ulna experiences anteroposterior bending. Three rosette strain gauges were attached around the circumference of the bone slightly distal to midshaft. They permit a complete characterization of the ulna's loading …
Uniqueness of primate forelimb posture during quadrupedal locomotion
Among the characteristics that are thought to set primate quadrupedal locomotion apart from that of nonprimate mammals are a more protracted limb posture and larger limb angular excursion. However, kinematic aspects of primate or nonprimate quadrupedal locomotion have been documented in only a handful of species, and more widely for the hind than the forelimb. This study presents data on arm (humerus) and forelimb posture during walking for 102 s…
Uniqueness of primate forelimb posture during quadrupedal locomotion
Among the characteristics that are thought to set primate quadrupedal locomotion apart from that of nonprimate mammals are a more protracted limb posture and larger limb angular excursion. However, kinematic aspects of primate or nonprimate quadrupedal locomotion have been documented in only a handful of species, and more widely for the hind than the forelimb. This study presents data on arm (humerus) and forelimb posture during walking for 102 s…
Patterns of strain in the macaque tibia during functional activity
Patterns of strain in the macaque tibia during functional activity
The strain environment of the tibial midshaft of two female macaques was evaluated through in vivo bone strain experiments using three rosette gauges around the circumference of the bones. Strains were collected for a total of 123 walking and galloping steps as well as several climbing cycles. Principal strains and the angle of the maximum (tensile) principal strain with the long axis of the bone were calculated for each gauge site. In addition, …
Telemetered electromyography of the supinators and pronators of the forearm in gibbons and chimpanzees: Implications for the fundamental positional adaptation of hominoids
Extant apes are similar to one another, and different from monkeys, in features granting them greater range of forearm rotation and greater size of the muscles that produce this motion. Although these traits may have been independently acquired by the various apes, the possibility arises that such features reflect adaptation to the stem behavior of the hominoid lineage. Anticipating that knowledge of forearm rotatory muscle recruitment during bra…
Forearm rotation and the “origin of the hominoid lifestyle”: Response to Sarmiento
Mechanisms of force and power production in unsteady ricochetal brachiation
Brachiators travel by swinging beneath handholds, and it is not obvious how these animals manage to accelerate and decelerate in a horizontal direction, especially when moving rapidly. Most previous analyses focused on brachiation in highly constrained laboratory conditions that induced steady‐state locomotion. Emerging understanding of brachiation suggests that much of gibbon locomotory behavior and morphology must be considered within the conte…
Compliant walking in primates: Elbow and knee yield in primates compared to other mammals
It has been suggested that primates utilize a compliant gait to help reduce peak locomotor stresses on their limbs (Schmitt [ 1994 ] J. Hum. Evol. 26: 441–458; Schmitt [ 1998 ] Primate Locomotion , p. 175–200; Schmitt [ 1999 ] J. Zool. Lond. 248: 149–160). However, the components of such a gait, i.e., increased step length, prolonged contact time, and substantial limb yield, have only been documented on a handful of primate species. In order to e…
Maintenance of above-branch balance during primate arboreal quadrupedalism: Coordinated use of forearm rotators and tail motion
Animals that live and travel in trees display a variety of morphological and behavioral adaptations to help them maintain balance on narrow flexible supports. Among these adaptations are long tails that can be used as counterweights, and freely mobile limbs in order to reach discontinuous supports. Here we describe two additional ways in which these features can contribute to balance during arboreal locomotion. Electromyographic (EMG) recordings …
The Primitive Wrist of Homo floresiensis and Its Implications for Hominin Evolution
Whether the Late Pleistocene hominin fossils from Flores, Indonesia, represent a new species, Homo floresiensis, or pathological modern humans has been debated. Analysis of three wrist bones from the holotype specimen (LB1) shows that it retains wrist morphology that is primitive for the African ape-human clade. In contrast, Neandertals and modern humans share derived wrist morphology that forms during embryogenesis, which diminishes the probabil…
Evolutionary transformation of the hominin shoulder
Biology (31 works) · Anatomy (29 works) · Anatomy (25 works) · Primate Behavior and Ecology (23 works) · Primate (14 works) · Evolutionary biology (12 works) · Neuroscience (12 works) · Medicine (10 works) · Ecology (9 works) · Paleontology (9 works)