Postcranial Anatomy

The Late Pleistocene hominin fossil assemblage from Liujiang, South China include a fairly well-preserved cranium, a right os coxa, a complete sacrum, and other postcranial elements all belonging to a single individual. This rare discovery offers us a unique and singular opportunity in understanding this Late Pleistocene hominin's body proportion and relative cranial capacity (encephalization quotient [EQ]), and also pelvic morphology. Using the available right innominate and its mirror-imaged left side, we reconstruct Liujiang hominin's pelvis. Our analysis of the pelvis indicates that the Liujiang hominin has a very gracile and modern-like pelvic morphology. Indeed, all of the pelvic dimensions are smaller than those of other Pleistocene hominins. Moreover, the pelvic characteristics typical of Middle and Late Pleistocene hominins including Neanderthals cannot be identified in the Liujiang pelvis. In contrast, both Liujiang's metric and non-metric features indicate affinities to more recent human populations including our modern Chinese collections from Guangxi of south China. Further support of this assessment comes from the EQ value of 5.754 for Liujiang which is closer to Minatogawa 2 and modern Chinese populations than to Middle and Late Pleistocene fossil hominins. Our analysis of body shape shows that Liujiang has body proportion (i.e. body height relative to body breadth) typical of warm-adapted populations. Based on these findings, we reason that the modern physical characteristics of Liujiang may allude to a more recent geological age. Alternatively, its morphological “modernity” could also point to a much higher degree of skeletal variation within Late Pleistocene hominins in East Asia.

Tool-using hominids, as carnivorous animals, would have been part of the various carnivore guilds present in Plio-Pleistocene Africa. Hominid dietary strategies must be understood within the larger context of carnivore behavior and ecology, as carnivorans could have affected the abilities of hominids to procure meat and/or marrow. The functional anatomy of extant and fossil
carnivorans was examined to infer behaviors in fossil carnivorans that would have impacted on hominid dietary strategies in terms of carcass availability. Comparisons of guild structure were carried out to examine changes in carnivoran interactions and their implications for hominid behavior. Plio-Pleistocene carnivorans engaged in a wider range of behaviors than modern carnivorans. The sabertoothed felids Dinofelis and Megantereon
probably did not provide much larger carcasses than modern species. Another sabertooth, Homotherium generated larger carcasses, but may have disarticulated and transported these carcasses. Fossil representatives of modern taxa may not have been equivalent ecologically within the carnivoran guild. Overall, hominids in eastern Africa probably had a greater range of scavenging opportunities than did those of southern Africa during the Plio-Pleistocene. Local and continent-wide extinction events in large-bodied carnivoran guilds from 1 to 2 Ma had a substantial effect on carcass availability and the risk to
hominid scavengers. These structural changes in the carnivore guild may have provided an opportunity for hominids to widen their niche with respect to dietary behavior.

Characters of cranial and postcranial osteology provide important data for examining the interordinal relationships of mammals. Understanding variation in the cranial and postcranial skeleton is necessary for adequately representing ancestral character states for each mammalian order. This paper provides a comprehensive description and discussion of cranial and postcranial osteology in one of the major perissodactyl lineages, the Tapiromorpha, the lineage including the extant rhinoceroses and tapirs and their fossil relatives. Tapiromorph skeletal morphology is described, and tapiromorphs are compared to each other, to other perissodactyls, and to a number of other eutherians. Characters of potential phylogenetic significance are emphasized. A phylogenetic analysis of tapiromorphs using cranial and postcranial osteological characters provides a number of interesting results. The data do not support placing Homogalax and Chalicotherioidea within Tapiromorpha. The data support several novel hypotheses regarding the phylogeny of rhinocerotoids, including a close relationship between rhinocerotids and amynodontids, relative to hyracodontids. Finally, examples of the relevance of tapiromorph osteology to understanding perissodactyl origins are discussed, particularly new interpretations of certain primitive character states for perissodactyls.

Characters of cranial and postcranial osteology provide important data for examining the interordinal relationships of mammals. Understanding variation in the cranial and postcranial skeleton is necessary for adequately representing ancestral character states for each mammalian order. This paper provides a comprehensive description and discussion of cranial and postcranial osteology in one of the major perissodactyl lineages, the Tapiromorpha, the lineage including the extant rhinoceroses and tapirs and their fossil relatives. Tapiromorph skeletal morphology is described, and tapiromorphs are compared to each other, to other perissodactyls, and to a number of other eutherians. Characters of potential phylogenetic significance are emphasized. A phylogenetic analysis of tapiromorphs using cranial and postcranial osteological characters provides a number of interesting results. The data do not support placing Homogalax and Chalicotherioidea within Tapiromorpha. The data support several novel hypotheses regarding the phylogeny of rhinocerotoids, including a close relationship between rhinocerotids and amynodontids, relative to hyracodontids. Finally, examples of the relevance of tapiromorph osteology to understanding perissodactyl origins are discussed, particularly new interpretations of certain primitive character states for perissodactyls.

In this study, a new Early Pleistocene proximal hand phalanx (ATE9-2) from the Sima del Elefante cave site (TE - Sierra de Atapuerca, Spain), ascribed to Homo sp., is presented and comparatively described in the context of the evolution of the genus Homo. The ATE9-2 specimen is especially important because of the paucity of hand bones in the human fossil record during the Early Pleistocene. The morphological and metrical analyses of the phalanx ATE9-2 indicate that there are no essential differences between it and comparator fossil specimens for the genus Homo after 1.3 Ma (millions of years ago). Similar to Sima de los Huesos and Neandertal specimens, ATE9-2 is a robust proximal hand phalanx, probably reflecting greater overall body robusticity in these populations or a higher gracility in modern humans. The age of level TE9 from Sima del Elefante and morphological and metrical studies of ATE9-2 suggest that the morphology of the proximal hand phalanges and, thus, the morphology of the hand could have remained stable over the last 1.2e1.3 Ma. Taking into account the evidence recently provided by a metacarpal from Kaitio (Kenya) from around 1.42 Ma, we argue that modern hand morphology is present in the genus Homo subsequent to Homo habilis.

The species of the subfamily Uromastycinae are herbivorous burrowing lizards distributed from the African Sahara Desert to the Asian Thar Desert and across the Arabian Peninsula. Although osteological studies on Uromastycinae have a long history, a detailed description of the complete skeleton is lacking. We investigate the cranial and postcranial osteology of the Mesopotamian Spiny-tailed Lizard (Saara loricata, previously referred to Uromastyx). We studied articulated and disarticulated materials from five specimens and present a complete description of the bones of the species. Our study adds to the growing body of literature on the skeleton of agamid lizards. Unlike Uromastyx sensu stricto, in S. loricata no anterior premaxillary foramina exists on the anterior surface of the premaxilla, no contact exists between the frontal and the maxilla or premaxilla, the anterolateral processes of the frontal are unexposed in dorsal view so that the prefrontal and nasal are attached, and the pterygoid does not contact the vomer anteriorly and the quadrate posteriorly. Unlike its congener S. hardwickii, in S. loricata no anterior premaxillary foramen exists on the anterior surface of the premaxilla, a smaller ethmoidal foramen perforates the nasal, a well-developed, posteriorly extended socket-like notch is formed through anterior bifurcation of the jugal, an L-shaped suture line forms between the jugal and postorbital in dorsal view, and an interlocking suture between the surangular and dentary exists in S. loricata.

The initial appearance of hominoids, or apes, and the selective pressures that led to their emergence are currently disputed. Central to the argument are the proconsulids, variously described as the earliest apes or as stem catarrhines, based on facial and postcranial data, respectively. The present paper reports on incongruence and parsimony analyses applied to a combined data set. The results demonstrate that proconsulids are cladistic hominoids, and that the apparent incongruence between the data sets is due to mosaic evolution; the earliest changes in Hominoidea occurred in the face. These results suggest that the initial divergence of hominoids involved selection for an ape-like face, and was not driven by an adaptive shift to below-branch locomotion.

Reconstructing the behaviour and ecology of extinct felids, especially that of machairodontine felids, has been of great interest within the field of vertebrate paleontology. The anatomical design of these animals has been investigated with respect to dental function and prey acquisition behaviour, and, to a lesser degree, locomotion.

Few large felids exist today, and machairodontine felids were sometimes even larger than the largest extant felids, lions and tigers. This leads to the question of how much of the morphology observed in large machairodontines is simply an extension of size-related shape trends observed in modern felids. That is, to what extent are the morphological differences between machairodontines and smaller extant felids due to differences in size? Which extinct forms appear to be scaled-up versions of smaller felids, and which ones exhibit morphology indicative of functional differences?

This preliminary study investigates machairodontine postcranial morphology in light of scaling patterns in extant felids and examines how well trends in smaller extant felids predict the morphology of larger felids.We also look for any overall trends in machairodontine postcranial morphology that unite them
as a group, much like the possession of machairodont dentition does.

The species of the subfamily Uromastycinae are herbivorous burrowing lizards distributed from the African Sahara Desert to the Asian Thar Desert and across the Arabian Peninsula. Although osteological studies on Uromastycinae have a long history, a detailed description of the complete skeleton is lacking. We investigate the cranial and postcranial osteology of the Mesopotamian Spiny-tailed Lizard (Saara loricata, previously referred to Uromastyx). We studied articulated and disarticulated materials from five specimens and present a complete description of the bones of the species. Our study adds to the growing body of literature on the skeleton of agamid lizards. Unlike Uromastyx sensu stricto, in S. loricata no anterior premaxillary foramina exists on the anterior surface of the premaxilla, no contact exists between the frontal and the maxilla or premaxilla, the anterolateral processes of the frontal are unexposed in dorsal view so that the prefrontal and nasal are attached, and the pterygoid does not contact the vomer anteriorly and the quadrate posteriorly. Unlike its congener S. hardwickii, in S. loricata no anterior premaxillary foramen exists on the anterior surface of the premaxilla, a smaller ethmoidal foramen perforates the nasal, a well-developed, posteriorly extended socket-like notch is formed through anterior bifurcation of the jugal, an L-shaped suture line forms between the jugal and postorbital in dorsal view, and an interlocking suture between the surangular and dentary exists in S. loricata.

This study compares fossil femora attributed to extinct African bunodont lutrines with extant mustelids and ursids to reconstruct locomotor behavior. Due to the immense size differences among taxa, shape data were used to compare morphology. Based on morphological differences, the fossil femora are suggested to belong to different taxa with different locomotor abilities and habitat preferences. The Langebaanweg femur is the oldest and has a typical mustelid morphology suggesting that it was a locomotor generalist like most mustelids. The West Turkana form is more like extant nonbunodont otters, but much larger, and may have belonged to a semiaquatic taxon. The enormous Omo femur shares some features with truly aquatic taxa (e.g., Enhydra) and is the most likely to have been fully aquatic. The same may hold true for the Hadar species as it is most similar to that from the Omo. If these femora truly belong to bunodont lutrines, then they are more diverse in postcranial morphology than in dental morphology.

Objectives: Integration and modularity reflect the coordinated action of past evolutionary processes and, in turn, constrain or facilitate phenotypic evolvability. Here, we analyze magnitudes of integration in the macaque postcranium to test whether 20 a priori defined modules are (1) more tightly integrated than random sets of postcranial traits, and (2) are differentiated based on mode of definition, with developmental modules expected to be more integrated than functional or anatomical modules. Materials and Methods: The 3D morphometric data collected for eight limb and girdle bones for 60 macaques were collated into anatomical, developmental, and functional modules. A resampling technique was used to create random samples of integration values for each module for statistical comparison. Results: Our results found that not all a priori defined modules were more strongly integrated than random samples of postcranial traits and that specific types of modules did not present consistent patterns of integration. Rather, girdle and joint modules were consistently less integrated than limb modules, and forelimb elements were less integrated than hindlimbs. Discussion: The results suggest that morphometrically complex modules tend to be less integrated than simple limb bones, irrespective of the number of available traits. However, differences in inte

In this study, a new Early Pleistocene proximal hand phalanx (ATE9-2) from the Sima del Elefante cave site (TE - Sierra de Atapuerca, Spain), ascribed to Homo sp., is presented and comparatively described in the context of the evolution of the genus Homo. The ATE9-2 specimen is especially important because of the paucity of hand bones in the human fossil record during the Early Pleistocene. The morphological and metrical analyses of the phalanx ATE9-2 indicate that there are no essential differences between it and comparator fossil specimens for the genus Homo after 1.3 Ma (millions of years ago). Similar to Sima de los Huesos and Neandertal specimens, ATE9-2 is a robust proximal hand phalanx, probably reflecting greater overall body robusticity in these populations or a higher gracility in modern humans. The age of level TE9 from Sima del Elefante and morphological and metrical studies of ATE9-2 suggest that the morphology of the proximal hand phalanges and, thus, the morphology of...

Much debate surrounds the phylogenetic affinities of the endemic Greater Antillean platyrrhines. Thus far, most phylogenetic analyses have been constructed and tested using craniodental characters. We add to this dialog by considering how features of the distal humerus support or refute existing hypotheses for the origins of fossil Caribbean primates, utilizing three-dimensional geometric morphometric data in combination with character based cladistic analyses. We also add to the sample of fossil platyrrhine humeri with the description of UF 114718, a new distal humerus from Haiti. We reconstruct UF 114718 to be a generalized, arboreal quadruped attributed to the species Insulacebus toussantiana. Our results from phylogenetic analyses lend some support to the idea that some Greater Antillean fossil taxa including Xenothrix mcgregori, Antillothrix bernensis, and Insulacebus toussaintiana could form a monophyletic clade that is sister to either extant Platyrrhini or basal pitheciids. Based on the distal humeral data, we reconstruct the earliest ancestral platyrrhine to be a generalized, arboreal quadruped that potentially emphasized pronated arm postures during locomotion and may have engaged in some limited climbing, most similar in shape to early anthropoids and some of the earliest Antillean forms. However, aspects of shape and standard qualitative characters relating to the distal humerus seem to be variable and prone to both homoplasy and reversals; thus these results must be interpreted cautiously and (where possible) within the context provided by other parts of the skeleton.

Specimens initially collected but not reported from the original type locality of Cornwallius sookensis (Mammalia, Desmostylia) have been found at the National Museum of Natural History in Washington, DC. Two femora and a partial skull were collected from the same locality as the holotype that was deposited by Ira Cornwall in the Royal British Columbia Provincial Museum in the 1920s. Though the partial skull is missing from the collection, the femora remain. They are small and lack epiphyses, possibly from breakage or immaturity. Muscle scars suggest that adductors, extensors and lateral rotators were strongly developed, indicating that their posture was of the normal mammalian upright nature. The sectioned end of USNM 11076 permits inspection of characteristics of the medullary canal and cortical.