This study addresses how the human temporal bone develops the population-specific pattern of morp... more This study addresses how the human temporal bone develops the population-specific pattern of morphology observed among adults and at what point in ontogeny those patterns arise. Threedimensional temporal bone shape was captured using 15 landmarks on ontogenetic series of specimens from seven modern human populations. Discriminant function analysis revealed that populationspecific temporal bone morphology is evident early in ontogeny, with significant shape differences among many human populations apparent prior to the eruption of the first molar. As early as five years of age, temporal bone shape reflects population history and can be used to reliably sort populations, although those in closer geographic proximity and molecular affinity are more likely to be misclassified. The deviation of cold-adapted populations from this general pattern of congruence between temporal bone morphology and genetic distances, identified in previous work, was confirmed here in adult and subadult specimens, and was revealed to occur earlier in ontogeny than previously recognized. Significant differences exist between the ontogenetic trajectories of some pairs of populations, but not among others, and the angles of these trajectories do not reflect genetic relationships or final adult temporal bone size. Significant intrapopulation differences are evident early in ontogeny, with differences becoming amplified by divergent trajectories in some groups. These findings elucidate how the congruence between adult human temporal bone morphology and population history develops, and reveal that this pattern corresponds closely to that described previously for facial ontogeny.
This study investigates the gross anatomy of the original and the regenerated tail in the green a... more This study investigates the gross anatomy of the original and the regenerated tail in the green anole (Anolis carolinensis). Dissections were conducted on 24 original and 13 regenerated tails. While the extrinsic muscles of the original tail in A. carolinensis are similar to those in other known Anolis lizard species, the extent of the origins of m. caudofemoralis longus and m. caudofemoralis brevis is more restricted. These differences may underlie variation in locomotor performance among anole ecomorphs. The intrinsic muscles of the original tail are also described, confirming previous findings and documenting new details, includingmuscle origins and insertions and the range of intraspecific variation. A comparison of the intrinsic muscles of the original tail and the regenerated tail muscles reveals key differences, such as the lack of interdigitating muscle segments and intramuscular septa in the regenerated tail. These findings, along with the replacement of interlocking vertebrae with a stiff, cartilaginous rod, suggest that important functional differences exist between the original and regenerated tail. In particular, the regenerated tail is predicted to be less capable of coordinated, fine movements. Studies of the physical properties and range of motion of the original and regenerated tail are required to test this hypothesis. This atlas of tail anatomy in A. carolinensis represents a key resource for developmental and genetic studies of tail regeneration in lizards, as well as studies of anole evolution and biomechanics.
Since its discovery in southeastern Uzbekistan in 1938, the Teshik-Tash child has been considered... more Since its discovery in southeastern Uzbekistan in 1938, the Teshik-Tash child has been considered a Neandertal. Its affinity is important to studies of Late Pleistocene hominin growth and development as well as interpretations of the Central Asian Middle Paleolithic and the geographic distribution of Neandertals. A close examination of the original Russian monograph reveals the incompleteness of key morphologies associated with the cranial base and face and problems with the reconstruction of the Teshik-Tash cranium, making its Neandertal attribution less certain than previously assumed. This study reassesses the Neandertal status of Teshik-Tash 1 by comparing it to a sample of Neandertal, Middle and Upper Paleolithic modern humans, and recent human sub-adults. Separate examinations of the cranium and mandible are conducted using multinomial logistic regression and discriminant function analysis to assess group
This study addresses how the human temporal bone develops the population-specific pattern of morp... more This study addresses how the human temporal bone develops the population-specific pattern of morphology observed among adults and at what point in ontogeny those patterns arise. Threedimensional temporal bone shape was captured using 15 landmarks on ontogenetic series of specimens from seven modern human populations. Discriminant function analysis revealed that populationspecific temporal bone morphology is evident early in ontogeny, with significant shape differences among many human populations apparent prior to the eruption of the first molar. As early as five years of age, temporal bone shape reflects population history and can be used to reliably sort populations, although those in closer geographic proximity and molecular affinity are more likely to be misclassified. The deviation of cold-adapted populations from this general pattern of congruence between temporal bone morphology and genetic distances, identified in previous work, was confirmed here in adult and subadult specimens, and was revealed to occur earlier in ontogeny than previously recognized. Significant differences exist between the ontogenetic trajectories of some pairs of populations, but not among others, and the angles of these trajectories do not reflect genetic relationships or final adult temporal bone size. Significant intrapopulation differences are evident early in ontogeny, with differences becoming amplified by divergent trajectories in some groups. These findings elucidate how the congruence between adult human temporal bone morphology and population history develops, and reveal that this pattern corresponds closely to that described previously for facial ontogeny.
This study investigates the gross anatomy of the original and the regenerated tail in the green a... more This study investigates the gross anatomy of the original and the regenerated tail in the green anole (Anolis carolinensis). Dissections were conducted on 24 original and 13 regenerated tails. While the extrinsic muscles of the original tail in A. carolinensis are similar to those in other known Anolis lizard species, the extent of the origins of m. caudofemoralis longus and m. caudofemoralis brevis is more restricted. These differences may underlie variation in locomotor performance among anole ecomorphs. The intrinsic muscles of the original tail are also described, confirming previous findings and documenting new details, includingmuscle origins and insertions and the range of intraspecific variation. A comparison of the intrinsic muscles of the original tail and the regenerated tail muscles reveals key differences, such as the lack of interdigitating muscle segments and intramuscular septa in the regenerated tail. These findings, along with the replacement of interlocking vertebrae with a stiff, cartilaginous rod, suggest that important functional differences exist between the original and regenerated tail. In particular, the regenerated tail is predicted to be less capable of coordinated, fine movements. Studies of the physical properties and range of motion of the original and regenerated tail are required to test this hypothesis. This atlas of tail anatomy in A. carolinensis represents a key resource for developmental and genetic studies of tail regeneration in lizards, as well as studies of anole evolution and biomechanics.
Since its discovery in southeastern Uzbekistan in 1938, the Teshik-Tash child has been considered... more Since its discovery in southeastern Uzbekistan in 1938, the Teshik-Tash child has been considered a Neandertal. Its affinity is important to studies of Late Pleistocene hominin growth and development as well as interpretations of the Central Asian Middle Paleolithic and the geographic distribution of Neandertals. A close examination of the original Russian monograph reveals the incompleteness of key morphologies associated with the cranial base and face and problems with the reconstruction of the Teshik-Tash cranium, making its Neandertal attribution less certain than previously assumed. This study reassesses the Neandertal status of Teshik-Tash 1 by comparing it to a sample of Neandertal, Middle and Upper Paleolithic modern humans, and recent human sub-adults. Separate examinations of the cranium and mandible are conducted using multinomial logistic regression and discriminant function analysis to assess group
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Papers by Terry Ritzman
species, the extent of the origins of m. caudofemoralis longus and m. caudofemoralis brevis is more restricted. These differences may underlie variation in locomotor performance among anole ecomorphs. The intrinsic muscles of the original tail are also described, confirming previous findings and documenting new details, includingmuscle origins and insertions and the range of intraspecific variation. A comparison of the intrinsic muscles of the original tail and the regenerated tail muscles reveals key differences, such as the lack of interdigitating muscle segments and intramuscular septa in the regenerated tail. These findings, along with the replacement of interlocking vertebrae with a stiff, cartilaginous rod, suggest that important functional differences exist between the original and regenerated tail. In particular, the regenerated tail is predicted to be less capable of coordinated, fine movements. Studies of the
physical properties and range of motion of the original and regenerated tail are required to test this hypothesis. This atlas of tail anatomy in A. carolinensis represents a key resource for developmental and genetic studies of tail regeneration in lizards, as well as studies of anole evolution and biomechanics.
species, the extent of the origins of m. caudofemoralis longus and m. caudofemoralis brevis is more restricted. These differences may underlie variation in locomotor performance among anole ecomorphs. The intrinsic muscles of the original tail are also described, confirming previous findings and documenting new details, includingmuscle origins and insertions and the range of intraspecific variation. A comparison of the intrinsic muscles of the original tail and the regenerated tail muscles reveals key differences, such as the lack of interdigitating muscle segments and intramuscular septa in the regenerated tail. These findings, along with the replacement of interlocking vertebrae with a stiff, cartilaginous rod, suggest that important functional differences exist between the original and regenerated tail. In particular, the regenerated tail is predicted to be less capable of coordinated, fine movements. Studies of the
physical properties and range of motion of the original and regenerated tail are required to test this hypothesis. This atlas of tail anatomy in A. carolinensis represents a key resource for developmental and genetic studies of tail regeneration in lizards, as well as studies of anole evolution and biomechanics.