Postcranial evidence of cold adaptation in European Neandertals

The low brachial and crural indices of the European Neandertals have long been considered indicative of cold adaptation. Recent work has documented lower limb/trunk ratios and deeper chests (anterior-posterior diameter) in European Neandertals than among their successors. The present study uses variables reflective of limb length, body mass and trunk height, and compares European Neandertals to 15 globally diverse recent human samples (1 “Eskimo,” 3 North African, 4 sub-Saharan African and 7 European). Bivariate plots, as well as principal components analysis plots of log shape-transformed data, indicate that European Neandertals had an overall body shape that falls at the extreme end of modern higher latitude groups' range of variation. Cluster analysis (minimum spanning tree on a principal coordinates plot) indicates that the Neandertals are closest in body shape to modern “Eskimos,” but even in this dendrogram, they are joined to the “Eskimo” via a long branch. In fact, it appears that European Neandertals were “hyperpolar” in body shape, likely due to two factors: 1) the extremely cold temperatures of glacial Europe and 2) less effective cultural buffering against cold stress. Am J Phys Anthropol 104:245–258, 1997. © 1997 Wiley-Liss, Inc.     

A new lorisid humerus from the early miocene of Uganda

An early Miocene (18–20 mya) distal humerus from Napak, Uganda, is the only element of the forelimb to be allocated to African Lorisinae. Its loris-like features distinguish it from other East African material that more closely resembles galagids. Tracing the evolution of the lorisoid body has been a difficult task due to the lack of good fossil material. Here, we add a single specimen to this poor record. This humerus helps to document the beginning of extant lorisid locomotor specialization and function.     

Stratigraphic interpretation of the Kulu Formation (Early Miocene, Rusinga Island, Kenya) and its implications for primate evolution

Early Miocene fossils from Rusinga Island, Kenya, provide some of the best evidence for catarrhine evolution and diversification, and, together with more than eighty-five other mammalian species, form an important comparative reference for understanding faunal succession in East Africa. While there is consensus over the stratigraphic position of most of Rusinga's volcaniclastic deposits, the lacustrine Kulu Formation has been placed in various parts of the geological sequence by different researchers. To resolve this discrepancy, we conducted detailed geological analyses which indicate that the Kulu Formation was formed in the Early Miocene during a period of volcanic inactivity and subsidence following the early, mainly explosive hyper-alkaline phase of the Kisingiri complex and prior to the final eruptions of nephelinitic lavas. The underlying Hiwegi and older formations were locally deformed and deeply eroded before sedimentation began in the Kulu basin, so that the Kulu sediments may be significantly younger than the 17.8 Ma Hiwegi Formation and not much older than the overlying Kiangata Agglomerata-Lunene Lava series, loosely dated to ca. 15 Ma. The overall similarities between Kulu and Hiwegi faunas imply long-term ecological stability in this region. Our stratigraphic interpretation suggests that the Kulu fauna is contemporaneous with faunas from West Turkana, implying that differences between these assemblages—particularly in the primate communities—reflect paleobiogeographic and/or paleocological differences. Finally, the position of the Kulu Formation restricts the time frame during which the substantial faunal turnover seen in the differences between the primate and mammalian communities of Rusinga and Maboko Islands could have occurred.     

A new stage in the evolution of the mole rats (Rodentia,Spalacinae) from the Early Miocene of northern Greece

The cheek teeth of Debruijnia kostakii n. sp. from the Early Miocene of Karydia are only slightly smaller than those of the largest extant species of the Spalacinae (Spalax giganteus), but show characteristics that are reminiscent of its Paleogene cricetid ancestor. The peculiar combination of large size and primitive dental morphology of this species bridges the gap between Debruijnia and Pliospalax and thereby supports the hypothesis that these genera form the core of the complex evolutionary history leading to extant Spalax.     

Allometry and adaptation in the catarrhine postcranial skeleton

Seven measurements were taken on the postcranial skeleton of 249 specimens representing ten species of catarrhine primates and tested to determine their relationship with size. Size was measured as skeletal weight on each individual. It was found that the interspecific line based on the entire sample was in some cases determined not only by morphological adjustments for size variation but also by changes in locomotor adaptations of differently sized species within the sample. It is suggested that it is consequently preferable to study allometric relationships within a species or within a group of species that differ in size but are similar in their mode of locomotion. The allometric analysis reveals some interesting patterns within the data. Limb lengths scaled with either negative allometry or isometry over the entire sample. Within the species groups isometry was the rule except for pongid femurs, which showed negative scaling. Humerus length scaled at the same rate in pongids as in cercopithecoids but had a slightly higher intercept value. While colobines and cercopithecines scaled at similar rates for all seven dimensions, the colobine line was shifted to a position above that for cercopithecines in every case. It is suggested that this is a result of adaptation for leaping in the former group. Other implications of the allometric results are discussed.     

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.     

Mediolateral reaction forces and forelimb anatomy in quadrupedal primates: implications for interpreting locomotor behavior in fossil primates

The forelimb joints of terrestrial primate quadrupeds appear better able to resist mediolateral (ML) shear forces than those of arboreal quadrupedal monkeys. These differences in forelimb morphology have been used extensively to infer locomotor behavior in extinct primate quadrupeds. However, the nature of ML substrate reaction forces (SRF) during arboreal and terrestrial quadrupedalism in primates is not known. This study documents ML-SRF magnitude and orientation and forelimb joint angles in six quadrupedal anthropoid species walking across a force platform attached to terrestrial (wooden runway) and arboreal supports (raised horizontal poles). On the ground all subjects applied a lateral force in more than 50% of the steps collected. On horizontal poles, in contrast, all subjects applied a medially directed force to the substrate in more than 75% of the steps collected. In addition, all subjects on arboreal supports combined a lower magnitude peak ML-SRF with a change in the timing of the ML-SRF peak force. As a result, during quadrupedalism on the poles the overall SRF resultant was relatively lower than it was on the runway. Most subjects in this study adduct their humerus while on the poles. The kinetic and kinematic variables combine to minimize the tendency to collapse or translate forelimbs joints in an ML plane in primarily arboreal quadrupedal primates compared to primarily terrestrial quadrupedal ones. These data allow for a more complete understanding of the anatomy of the forelimb in terrestrial vs. arboreal quadrupedal primates. A better understanding of the mechanical basis of morphological differences allows greater confidence in inferences concerning the locomotion of extinct primate quadrupeds.     

Effect of reproductive state and body size on food consumption in captive Galago senegalensis braccatus

Measurements of food consumption for different types of foods were made for seven Galago senegalensis braccatus. Differences because of reproductive state in females and body size were found. Lactating females consumed more food in total and had greater energy and protein intake than they did during other reproductive states. Near-term pregnant females consumed less food, energy, and protein than they did during other reproductive states. Body size affected food intake, with smaller animals ingesting more per unit metabolic weight than larger subjects.     

Early Miocene Amphibians (Caudata, Salientia) from the Mokrá-Western Quarry (Czech Republic) with comments on the evolution of Early Miocene amphibian assemblages in Central Europe

The Mokrá-Western Quarry exhibits the rare occurrence of Early Miocene (MN 4) vertebrate fauna within the area of the eastern part of Central Europe. In addition to a rich fauna of reptiles and mammals, two fossiliferous karst joints (Mokrá-Western Quarry, 1/2001 Turtle Joint and Mokrá-Western Quarry, 2/2003 Reptile Joint) yielded a rich fauna of amphibians including 13 amphibian taxa: Salamandridae: Mioproteus sp., Chelotriton sp., type I, Chelotriton sp., type II, Triturus aff. roehrsi, Triturus cf. marmoratus, Triturus sp. (T. cristatus species group), Chioglossa meini, Mertensiella mera, Salamandridae gen. and sp. indet.; Pelobatidae: Pelobates sanchizi; Ranidae: Rana sp. (synklepton Rana esculenta); Bufonidae: Bufo sp. The first records of the West European species Triturus cf. marmoratus and Chioglossa meini are reported from the eastern part of Central Europe indicating the wide distribution of those taxa throughout the whole of Europe as early as MN 4. The oldest known record of Pelobates sanchizi documents the Early Miocene presence of representatives closely related to the extinct Late Oligocene representatives of Pelobates. The slow evolution of amphibian species is documented by the presence of Triturus cf. marmoratus and the oldest known occurrence of the extinct salamander Mertensiella mera.     

The calcaneus of Australopithecus afarensis and its implications for the evolution of bipedality

Calcanei from African apes, modern humans, and Australopithecus afarensis are compared to investigate the anatomical and mechanical changes that occurred in this bone as a result of the transition to terrestrial bipedality. Features analyzed include the cross-sectional area and volume of the calcaneal tuber, the geometry and orientation of the articular surfaces, and the surface topography of the calcaneal corpus. Calcaneal morphology is unequivocal in its partitioning of quadrupedal pongids and bipedal hominids.     

The ischium and hip extensor mechanism in human evolution

Although it is commonly stated that the ischia of the late Pliocene–early Pleistocene hominid fossils are long and ape-like, new interpretations show this view to be fallacious. An important new theory proposed by Robinson concludes that the gracile form of early hominid was an efficient biped, but the robust form was a less efficient biped and was adapted for tree climbing. Interpretation of the ischium is crucial to this idea. The present study shows that (1) the gracile and robust australopithecine ischia had similar relative lengths and (2) that the hamstring mechanism was probably very similar in the two forms of South African early hominid.     

A functional multivariate analysis of Mesopithecus (Primates: Colobinae) humeri from the Turolian of Greece

The genus Mesopithecus is well represented in the late Miocene of Greece by several recognized species. The present paper investigates functional aspects of the humeri of Mesopithecus delsoni/pentelicus, M. pentelicus and M. aff. pentelicus of several Turolian sites from central and northern Greece, using multivariate approaches. For these purposes, we selected significant humeral functional features, which were represented by 23 linear dimensions and three angles on 14 fossil humeri and 104 humeri from 10 genera and 22 species of extant African and Asian Colobines. All size-adjusted measurements were examined through a principal components analysis, followed by a discriminant function analysis, and a canonical variates analysis. All analyses revealed that the selected characters were able to discriminate between extant colobine genera. Functional groups, such as arboreal walking/climbing, arboreal walking/suspensory and semi-terrestrial walking, were set apart from a central cluster formed by the arboreal walking and arboreal walking/terrestrial groups. This cluster also grouped the three studied Mesopithecus species, which were mainly classified as arboreal walkers with significant terrestrial activities. These observations match with paleoenvironmental reconstructions and the suggested opportunistic feeding habits. Moreover, the overall arboreal/terrestrial locomotor tendencies of these fossil forms are discussed in relation to their earlier migration from Africa and later dispersal to eastern and southern Asia.     

Early evolution and biogeography of lorisiform strepsirrhines

This brief review summarizes new paleontological and molecular data that together support a late middle Eocene Afro-Arabian origin for crown Lorisiformes. Phylogenetic analysis indicates that late Eocene Karanisia is a possible stem lorisiform, late Eocene Saharagalago and Wadilemur and Miocene Komba are stem galagids, and early Miocene Mioeuoticus and Progalago may be crown lorisids. Character evolution along the lorisid and galagid stem lineages is reconstructed as having occurred primarily in postcranial and dental morphology, respectively. These patterns have important implications for interpreting an early lorisiform fossil record that is still composed primarily of jaws and isolated teeth.