Postcranial Morphology Research Articles

Do body proportions among Jomon foragers from Hokkaido conform to ecogeographic expectations? evolutionary implications of body size and shape among northerly hunter‐gatherers

AbstractThis study documents and interprets adaptive postcranial morphology among prehistoric Jomon period foragers from Hokkaido, Japan (HKJ). The Hokkaido climate is differentiated from other Japanese islands by freezing winters with sea‐ice accumulation in the northern regions. Increased brachial and crural indices are, however, observed among HKJ foragers, while body mass (BM) has not yet been estimated for these groups. Based on previous observations and paleoclimatic reconstructions, it was predicted that increased BM and increased distal relative to proximal limb lengths would typify HKJ foragers. Similar BM was observed between HKJ foragers and groups from colder environments. Intralimb indices do, however, suggest similarity between HKJ foragers and groups from high‐latitude, warm environments. It is likely that HKJ foragers retained cold‐derived BM in association with Pleistocene migrations to Hokkaido via Northeast Asia. That is, enlarged BM among HKJ foragers is associated with long‐term evolution in a colder environment. Relatively elongated distal limbs may represent morphological response to a slightly warmer environment. Following migration to Japan from a colder environment, elongation of distal limb segments resulted in elevated brachial and crural indices. Relatively elongated distal appendages may also reflect positive nutritional status as HKJ people experienced lesser rates of systemic stress than other Jomon groups. It is also possible that elongated distal relative to proximal limbs are associated with neutral mutation and genetic drift. This interpretation suggests a neutral mutation associated with relative limb length in some HKJ ancestor with subsequent spread of this allele through isolation and drift. Ontogenetic and temporal studies of intralimb indices among Jomon people are necessary to further evaluate these interpretations. Copyright © 2009 John Wiley & Sons, Ltd.

Postcranial morphology, functional adaptations and palaeobiology of Callistoe vincei, a predaceous metatherian from the Eocene of Salta, north-western Argentina

Callistoe vincei Babot et al., 2002 is a Paleogene borhyaenoid known from exceptionally complete postcranial elements, which provides rare information about the anat- omy and evolutionary history of metatherian predators dur- ing the South American Cenozoic. The axial skeleton of Callistoe is characterized by the peculiar transverse processes of the cervical vertebrae emphasizing lateral instead of sagit- tal traction. There is no clavicle and eighteen thoracolumbar vertebrae, of which only five are lumbars. The shoulder and elbow joints suggest movements restricted to parasagittal flexion ⁄ extension that are consistent with primarily terrestrial locomotion, as is also emphasized in Borhyaena tuberata and Lycopsis longirostrus. On the manus, the pollex is not reduced and the ungual phalanges indicate very long claws, similar to those observed in some extant digging taxa. This feature is unique to C. vincei among borhyaenoids. The knee joint is characterized by the presence of ossified patellae but shallow femoral trochleae. This joint suggests that the leg was nearly parasagittal, a position also inferred for Borhyaena. The astragalus shape is consistent with parasagittal flexion ⁄ exten- sion, as in all Miocene-Pliocene borhyaenoids. The hind foot is characterized by reduced claws in comparison with the manus as well as the slenderness of the first and fifth digits, another peculiarity of C. vincei. The habitat of Callistoe was a temperate humid forest and according to the known fossil record, Callistoe was the largest mammalian predator of its time, sharing the predator ecological niche with crocodiles.

Knuckle-walking in Sivapithecus? The combined effects of homology and homoplasy with possible implications for pongine dispersals

Sivapithecus is a Miocene great ape from South Asia that is orangutan-like cranially but is distinctive postcranially. Work by others shows that the humerus resembles large terrestrial cercopithecoids proximally and suspensory hominoids distally, but most functional interpretations nevertheless situate Sivapithecus in an arboreal setting. We present a new quantitative analysis of the Sivapithecus capitate and hamate. Though the functional morphology of both bones suggests some degree of arboreality, the overall morphology is most similar to knuckle-walking African apes. Other features of the Sivapithecus humerus and hind limb are also functionally consistent with knuckle-walking, and we suggest that this locomotor behavior is a valid alternative functional interpretation of the postcranial morphology. We speculate that knuckle-walking in Sivapithecus would have evolved independently from African apes, perhaps for similar ecological reasons. The discovery of a possible pongine knuckle-walker challenges the hypotheses that (1) knuckle-walking evolved only once in hominoids and (2) knuckle-walking is too highly specialized to be the positional behavior from which human bipedalism evolved. The possibility of knuckle-walking in Sivapithecus may help to explain not only the curious combination of characters that typify the postcranium but also the unique postcranial morphology of extant Pongo. Furthermore, it may clarify the distribution of fossil pongines across many ecological zones in Eurasia in the Miocene and Pleistocene, as well as, independently, the spread of African apes across a diversity of environments in equatorial Africa.

Spatial abilities, cognition and the pattern of Neanderthal and modern human dispersals

Neanderthals and anatomically modern humans (AMHs) are very closely related, although their skeletal morphology is distinct enough for them to be classified as separate species. Their physical differences, including the architecture of the skull and post-cranial skeletal proportions, do not explain the extinction of the Neanderthals as a species, however. The post-cranial morphology of the Neanderthals, which is generally believed to reflect an active lifestyle under cold conditions, falls within the range of modern human variation. Their cranial capacities are essentially identical and skull morphology does not convey any obvious adaptive advantage to either species. The existence of other, less easily discernible biological traits that might have contributed to the extinction of the Neanderthals – such as differences in reproductive rates or developmental histories – cannot be ruled out, but are not supported by current data. Behaviourally (culturally) based explanations for the process of replacement of Neanderthal populations by AMHs center on archaeological evidence for more complex patterns of social organisation, associated with the use of symbols and the development of new technologies. This paper explores the link between social complexity, spatial distribution and cognition during the Late Pleistocene, suggesting a mechanism whereby cognitive differences between hominid species may have arisen.

Diversity among African Pygmies

Although dissimilarities in cranial and post-cranial morphology among African pygmies groups have been recognized, comparative studies on skull morphology usually pull all pygmies together assuming that morphological characters are similar among them and different with respect to other populations. The main aim of this study is to compare cranial morphology between African pygmies and non-pygmies populations from Equatorial Africa derived from both the Eastern and the Western regions in order to test if the greatest morphological difference is obtained in the comparison between pygmies and non-pygmies. Thirty three-dimensional (3D) landmarks registered with Microscribe in four cranial samples (Western and Eastern pygmies and non-pygmies) were obtained. Multivariate analysis (generalized Procrustes analysis, Mahalanobis distances, multivariate regression) and complementary dimensions of size were evaluated with ANOVA and post hoc LSD. Results suggest that important cranial shape differentiation does occur between pygmies and non-pygmies but also between Eastern and Western populations and that size changes and allometries do not affect similarly Eastern and Western pygmies. Therefore, our findings raise serious doubt about the fact to consider African pygmies as a homogenous group in studies on skull morphology. Differences in cranial morphology among pygmies would suggest differentiation after divergence. Although not directly related to skull differentiation, the diversity among pygmies would probably suggest that the process responsible for reduced stature occurred after the split of the ancestors of modern Eastern and Western pygmies.

Long bone histology of sauropterygia from the lower Muschelkalk of the Germanic basin provides unexpected implications for phylogeny.

BackgroundSauropterygia is an abundant and successful group of Triassic marine reptiles. Phylogenetic relationships of Triassic Sauropterygia have always been unstable and recently questioned. Although specimens occur in high numbers, the main problems are rareness of diagnostic material from the Germanic Basin and uniformity of postcranial morphology of eosauropterygians. In the current paper, morphotypes of humeri along with their corresponding bone histologies for Lower to Middle Muschelkalk sauropterygians are described and interpreted for the first time in a phylogenetic context.Methodology/Principal Findings Nothosaurus shows a typical plesiomorphic lamellar-zonal bone type, but varying growth patterns and the occurrence of a new humerus morphotype point to a higher taxonomic diversity than was known. In contrast to the enormous morphological variability of eosauropterygian humeri not assigned to Nothosaurus, their long bone histology is relatively uniform and can be divided into two histotypes. Unexpectedly, both of these histotypes reveal abundant fibrolamellar bone throughout the cortex. This pushes the origin of fibrolamellar bone in Sauropterygia back from the Cretaceous to the early Middle Triassic (early Anisian). Histotype A is assigned to Cymatosaurus, a basal member of the Pistosauroidea, which includes the plesiosaurs as derived members. Histotype B is related to the pachypleurosaur Anarosaurus. Contrary to these new finds, the stratigraphically younger pachypleurosaur Neusticosaurus shows the plesiomorphic lamellar-zonal bone type and an incomplete endochondral ossification, like Nothosaurus.Conclusions/SignificanceHistological results hypothetically discussed in a phylogenetical context have a large impact on the current phylogenetic hypothesis of Sauropterygia, leaving the pachypleurosaurs polyphyletic. On the basis of histological data, Neusticosaurus would be related to Nothosaurus, whereas Anarosaurus would follow the pistosaur clade. Furthermore, the presence of fibrolamellar bone, which is accompanied with increased growth rates and presumably even with increased metabolic rates, already in Anarosaurus and Cymatosaurus can explain the success of the Pistosauroidea, the only sauropterygian group to survive into the Jurassic and give rise to the pelagic plesiosaur radiation.

New anatomical data and phylogenetic relationships of Chebsaurus algeriensis (Dinosauria, Sauropoda) from the Middle Jurassic of Algeria

New osteological details of the sauropod Chebsaurus algeriensis from the Middle Jurassic Aïssa formation of the Naama Province, Algeria, are presented. The described material belongs to two juvenile individuals. Recent field work has provided new cranial and post-cranial material. This new material presents a combination of plesiomorphic and apomorphic eusauropod characters adding more data to the skull and the post-cranial skeletal morphology. A phylogenetic analysis (237 characters, 39 taxa: 16 parsimonious trees of 479 steps, CI = 0.53, RI = 0.73) (Läng 2008) indicates an unsolved phylogenetic position of Chebsaurus within the non-neosauropod Eusauropoda. Indeed, Chebsaurus is positioned in a multifurcation with Middle Jurassic ‘cetiosaurids’ Lapparentosaurus madagascariensis, Ferganasaurus verzilini, ?Cetiosaurus mogrebiensis and Cetiosaurus oxoniensis from Oxford. This polytomy could be explained by numerous missing data and also by the incongruence of the informative characters for the Middle Jurassic basal eusauropods. The latter could result from an evolutive radiation that might have succeeded the extinction at the end of the Early Jurassic (Pliensbachian–Toarcian) and/or the Pangea break-up.

Dental maturational sequence and dental tissue proportions in the early Upper Paleolithic child from Abrigo do Lagar Velho, Portugal

Neandertals differ from recent and terminal Pleistocene human populations in their patterns of dental development, endostructural (internal structure) organization, and relative tissue proportions. Although significant changes in craniofacial and postcranial morphology have been found between the Middle Paleolithic and earlier Upper Paleolithic modern humans of western Eurasia and the terminal Pleistocene and Holocene inhabitants of the same region, most studies of dental maturation and structural morphology have compared Neandertals only to later Holocene humans. To assess whether earlier modern humans contrasted with later modern populations and possibly approached the Neandertal pattern, we used high-resolution microtomography to analyze the remarkably complete mixed dentition of the early Upper Paleolithic (Gravettian) child from Abrigo do Lagar Velho, Portugal, and compared it to a Neandertal sample, the late Upper Paleolithic (Magdalenian) child of La Madeleine, and a worldwide extant human sample. Some aspects of the dental maturational pattern and tooth endostructural organization of Lagar Velho 1 are absent from extant populations and the Magdalenian specimen and are currently documented only among Neandertals. Therefore, a simple Neandertal versus modern human dichotomy is inadequate to accommodate the morphostructural and developmental variation represented by Middle Paleolithic and earlier Upper Paleolithic populations. These data reinforce the complex nature of Neandertal-modern human similarities and differences, and document ongoing human evolution after the global establishment of modern human morphology.

Postcranial anatomy of Platypterygius americanus (Reptilia: Ichthyosauria) from the Cretaceous of Wyoming

ABSTRACT Ichthyosaurs remains from the Albian and Cenomanian of Wyoming have been assigned to Platypterygius americanus, but apart from structures of the distal humerus, few other unequivocal character states have been proposed to differentiate this species from its congeners. The purpose of this study was to reevaluate the postcranial morphology of Platypterygius americanus, in order to assess the validity of this species and distinguish postcranial traits relevant for specific diagnoses. Several applicable features were identified, including the location of extrazeugopodial facets on the distal humerus and femur, shape of the intermedium, relative degree of fusion within the atlas-axis complex, number of presacral centra, and varying lengths of the anterior caudal centra. Comparative assessment suggests that Platypterygius americanus is a valid taxon, and that it is possible to differentiate the various Platypterygius spp. independent of stratigraphical and/or geographical occurrence data. Nevertheless, a future review of cranial morphology in all Platypterygius spp. is necessary to bolster these conclusions.

Anatomy of the postcranial skeleton of “Miacis” uintensis (Mammalia: Carnivoramorpha)

ABSTRACT This paper provides the first detailed description of the only known postcranial skeletal elements of “Miacis” uintensis. The morphology of the skeleton differs markedly from previously described “miacids” (a paraphyletic assemblage of early fossil carnivoramorphans), invalidating the notion that all “miacids” were very similar in their postcranial morphology and locomotor styles. The majority of the differences indicate an animal less well adapted to an arboreal lifestyle than has been inferred for other early “miacid” carnivoramorphans. A phylogenetic analysis clearly nests “Miacis” uintensis within the paraphyletic array of taxa previously referred to as the “Miacidae,” in a position closer to the crown clade Carnivora than is Vulpavus, a “miacid” whose postcranium has been previously described. When compared with the early canid Hesperocyon, this specimen shares many features thought to relate to the acquisition of a more terrestrial mode of life. This result indicates that, in contrast to prior models suggesting arboreality for all “miacids,” at least one independent ‘descent from the trees’ occurred much earlier within the array of stem carnivoramorphan taxa.

The human lineage

The human lineage

The ontogeny of Holocene and Late Pleistocene human postcranial strength

While a wide variety of studies have focused on population variation in adult cross-sectional properties, relatively little is known about population variation in postcranial robusticity in immature individuals. Furthermore, the age at which the population differences readily detected in adults manifest during growth is also unknown. This research addresses these gaps in our current understanding through the analysis of immature humeral and femoral long bone strength. Cross-sectional geometry was used to compare the developmental trajectories of diaphyseal strength in Late Pleistocene Neandertal and modern human subadults to a sample of immature humans from seven geographically diverse Holocene populations. Population differences in size-standardized cross-sectional properties appear to be systemic and develop very early in ontogeny in the Holocene sample. In many cases, these differences are present before one year of age. In general, the Late Pleistocene fossil samples fit within the range of recent human variation in long bone strength. Population differences detected here are likely related to a combination of factors including activity patterns, genetic propensities, and nutritional status. These results highlight the complex mosaic of processes that result in adult postcranial robusticity, and suggest that further exploration of the developmental interplay between intrinsic and extrinsic influences on skeletal robusticity will likely enhance our understanding of adult postcranial morphology.

Optimal running speed and the evolution of hominin hunting strategies

Recent discussion of the selective pressures leading to the evolution of modern human postcranial morphology, seen as early as Homo erectus, has focused on the relative importance of walking versus running. Specifically, these conversations have centered on which gait may have been used by early Homo to acquire prey. An element of the debate is the widespread belief that quadrupeds are constrained to run at optimally efficient speeds within each gait, whereas humans are equally efficient at all running speeds. The belief in the lack of optimal running speeds in humans is based, however, on a number of early studies with experimental designs inadequate for the purpose of evaluating optimality. Here we measured the energetic cost of human running ( n = 9) at six different speeds for five minutes at each speed, with careful replicates and controls. We then compared the fit of linear versus curvilinear models to the data within each subject. We found that individual humans do, in fact, have speeds at which running is significantly less costly than at other speeds (i.e., an optimal running speed). In addition, we demonstrate that the use of persistence hunting methods to gain access to prey at any running speed, even the optimum, would be extremely costly energetically, more so than a persistence hunt at optimal walking speed. We argue that neither extinct nor extant hominin populations are as flexible in the chosen speeds of persistence hunting pursuits as other researchers have suggested. Variations in the efficiency of human locomotion appear to be similar to those of terrestrial quadrupeds.

Phylogenetic Analyses of Postcranial Skeletal Morphology in Didelphid Marsupials

In this study I provide a phylogenetic hypothesis for didelphid Marsupials including a suite of 114 postcranial characters. The postcranial evidence was cladistically analyzed separately and concatenated with a nonmolecular data set previously published (71 cranio-dental-external characters). A combined analysis was done including published IRBP (interphotoreceptor retinoid binding protein, 1158 bp), DMP-1 (dentin matrix protein 1, 1176 bp), and RAG-1 (recombinase-activating gene, 2790 bp) sequences to the nonmolecular data set. In order to compare and evaluate the influence of the inclusion of postcranial morphology to previous hypotheses, the taxon sampling of didelphine ingroup was almost similar to the one used in recent series of papers on didelphid phylogeny. The postcranial information includes 48 characters from the axial skeleton, 37 from the anterior limb, and 29 from the posterior limb. I present anatomical descriptions for each postcranial character, adding details of different conditions observed among didelphine ingroup, as well as some functional implications. Different hypotheses that are discussed as polymorphic characters are alternatively treated as composite entries (CO) and transformation series (TS) in morphological and combined analyses. Different codings of polymorphic postcranial characters produce topologies that in general are not contradictory. The principal difference is the loss of resolution of trees in TS analysis, compared to CO analysis in postcranial evidence, whereas the support values were in general low in both codings. The topology obtained from postcranial evidence supported some already recovered relationships, such as the monophyly of the large opossums (Didelphis, Philander, Chironectes, Lutreolina, and Metachirus), and several polytypic groups such as Didelphis, Monodelphis, Marmosops, Thylamys, Micoureus, and Philander. Additionally, the intermediate position of Hyladelphys between calorumyines and didelphines is kept in CO analysis. The inclusion of the postcranial data set to previous nonmolecular evidence causes little incongruence, although some modifications in the topology and support values were detected. The effect of different codings of polymorphic characters was similar respect to the postcranial-only data set. In this case, the topology obtained with CO analysis was also notably better resolved than TS analysis. Similarly to the postcranial-only analysis, the topologies obtained in the total morphological evidence applying the two kinds of codings are highly congruent, but the TS treatment seemed not to contribute to retention of more phylogenetic information, since the CO analysis was better resolved. The relationships obtained adding the postcranial evidence to published combined data set (i.e., morphology, IRBP, DMP-1, and RAG-1 sequences) were mostly better resolved and supported in the CO coding than the morphological analyses, although the TS coding causes loss of resolution in the strict consensus. In this sense, some strong differences on deep branch topology can be detected depending on the treatment applied to polymorphic entries and partitioned analyses (e.g., phylogenetic condition of the mouse opossums, nodes C and B). Including the postcranial evidence in the total data set, I also recovered the intermediate position of Hyladelphys, but never the distantly related clades recently recovered by the inclusion of RAG-1 sequences (clades B I in Gruber, K.F., R.S. Voss, and S.A. Jansa. 2007. Base-compositional heterogeneity in the RAG1 locus among didelphid marsupials: implications for phylogenetic inference and the evolution of GC content. Systematic Biology 56: 1–14). However, the position of Metachirus nudicaudatus and Tlacuatzin canescens is highly affected. Excluding the last gene, the partitioned combined analysis considering postcranial evidence was highly congruent with previous IRBP, morphology, and combined topologies, especially in the TS analysis, w

The femur of extinct bunodont otters in Africa (Carnivora, Mustelidae, Lutrinae)

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.

A partial skeleton and isolated humeri of Nothosaurus (Reptilia: Eosauropterygia) from Winterswijk, The Netherlands

ABSTRACT A rare partial postcranium and isolated humeri of Nothosaurus from the Lower Muschelkalk of Winterswijk, The Netherlands are described. The partial skeleton consists of a vertebral column with ribs, pectoral girdle elements, and incomplete forelimbs. Because current species-level taxonomy of Nothosaurus is based only on features of the skull, we examined the postcranial morphology in detail in order to assign the skeleton to a valid species. We focused on the humerus because this bone generally shows a complex morphology in Lower Muschelkalk Nothosaurus. Three different humerus morphotypes were recognized in the Winterswijk material, which were also seen among humeri from other Lower and lowermost Middle Muschelkalk localities such as Rüdersdorf and Oberdorla (both in Germany), and Gogolin (Poland). Morphotype I is characterized by a slender appearance with a bulky proximal end. The preaxial and postaxial edges of the shaft are very distinct, and the distal end is fan-shaped. Morphotype II is rather small and gracile with the distal end being only slightly fan-shaped. Morphotype III is rather large with an especially massive proximal end, and the distal end is thick and shovel-like. Ontogenetic variation could also be recognized within the morphotypes. One small humerus from Oberdorla belongs to a juvenile and cannot be assigned to a specific morphotype. Type II humeri belong to the N. winterswijkensis-N. marchicus clade. Type III may represent a sexual morph of type II humeri and type I a new species of Nothosaurus, or both may pertain to the nothosaurian Germanosaurus and/or the eosauropterygian Cymatosaurus.

How to build a mammalian super-predator

Questions surrounding the biology of large fossil predators that differ markedly from living forms have long intrigued palaeobiologists. Among such taxa few have excited more interest than sabertooth cats, whose distinctive hypertrophied canines are suggestive of killing behaviors and feeding ecologies that may have departed widely from those of extant carnivores. Moreover, considerable variation among sabertooth species is further suggestive of intriguing differences within the group. Behavior and ecology in another large, extinct mammalian carnivore, the Australian marsupial lion ( Thylacoleo carnifex), has also proven contentious. In this study, we assemble a wide range of cranio-dental and postcranial indices in a dataset including machairodont sabertooths, T. carnifex and an extensive sample of extant taxa in order to examine the palaeobiology of these charismatic fossil carnivores. Results of multivariate analyses point to significant relationships between behavior and overall body proportions in extant mammalian carnivores. Postcranial morphologies of two American dirk-tooth species of sabertooth ( Smilodon) depart greatly from those of living felids and group most closely with bears among living placentals. Scimitar-tooth species of Homotherium and Machairodus cluster with modern pantherine cats. The marsupial lion groups with Smilodon. If these latter two phylogenetically disparate clades do represent a specialized, robust ecomorph adapted to predation on large prey, then it is a body plan that might be effectively identified on the basis of a handful of ‘bear-like’ postcranial features in combination with a more typically ‘felid-like’ carnassialization of the cheektooth row.

The morphological distinctiveness of Homo sapiens and its recognition in the fossil record: Clarifying the problem

AbstractSpecies are historically differentiated entities that, osteologically, may be differentiated to inconveniently varying extents. Living Homo sapiens is a distinctive morphological entity that is easily distinguished in both cranial and postcranial morphology from all other living hominoids and from the vast majority of its fossil relatives. In this contribution, we offer several apparent cranial apomorphies of the living species, while recognizing that it is reasonable to expect some degree of overlap in the ranges of variation of individual characters among closely related species such as those within the genus Homo. No one aspect of morphological detail may be considered totally diagnostic within very close‐knit groups of this sort or, conversely, be regarded as blurring the identities of their components. Overlap in morphological detail may even be expected in cases where striking Gestalt differences exist between closely related species due to major developmental reorganization. As a result, while the morphological and, by extension, historical distinction between such highly differentiated species pairs as Homo neanderthalensis and Homo sapiens is effectively unequivocal, in a nod to the intrinsic untidiness of biology the hominid fossil record does offer some instances that are much more difficult to interpret. In such cases, most, but not all, of the cranial apomorphies of living Homo sapiens, are present in individual fossil specimens or apparent populations. This is true, for example, of a set of variably dated and archeologically associated, as well as mostly incomplete, South African fossils (for example, Border Cave, Boskop, Fish Hoek, and most Klasies River Mouth specimens). These specimens very closely resemble living Homo sapiens in preserved overall cranial structure, but most conspicuously lack bipartite brows and fully developed human chin configurations. Whatever resolutions hominid systematists may reach in such cases, it is clear that to resort reflexively to such pernicious if convenient devices as “archaic Homo sapiens” only obscures any potential signals of systematic diversity in what is increasingly evidently a highly complex late Pleistocene hominid record.

Postcranial evidence from early Homo from Dmanisi, Georgia

The Plio-Pleistocene site of Dmanisi, Georgia, has yielded a rich fossil and archaeological record documenting an early presence of the genus Homo outside Africa. Although the craniomandibular morphology of early Homo is well known as a result of finds from Dmanisi and African localities, data about its postcranial morphology are still relatively scarce. Here we describe newly excavated postcranial material from Dmanisi comprising a partial skeleton of an adolescent individual, associated with skull D2700/D2735, and the remains from three adult individuals. This material shows that the postcranial anatomy of the Dmanisi hominins has a surprising mosaic of primitive and derived features. The primitive features include a small body size, a low encephalization quotient and absence of humeral torsion; the derived features include modern-human-like body proportions and lower limb morphology indicative of the capability for long-distance travel. Thus, the earliest known hominins to have lived outside of Africa in the temperate zones of Eurasia did not yet display the full set of derived skeletal features.

Extraordinarily preserved specimen of the oldest known glirid from the middle Eocene of Messel (Rodentia)

ABSTRACT Gliridae is one of the oldest extant families of rodents with a fossil record dating back as far as the early Eocene. Eogliravus wildi, previously known from some isolated teeth from the European early Eocene, represents the oldest and most primitive glirid. The early middle Eocene oil shales of Messel, Germany, yielded an extraordinarily preserved specimen of E. wildi, exhibiting the virtually complete and articulated skeleton, the outline of the pelage, and gut contents consisting of various vegetable matter. E. wildi descended most probably from European small-sized microparamyine ischyromyids. Its protrogomorphous zygo-masseteric structure indicates that the myomorphy and hystricomorphy of the extant dormice evolved convergently to other rodent clades. The postcranial skeleton compares well with extant glirids. The postcranial morphology, proportions of the limb segments, bushy tail, and small body size indicate a gracile and swift animal moving among tree branches. The very large orbits suggest nocturnal activity. E. wildi was well adapted to an arboreal or scrub environment, the major habitat of today's dormice.