La Ferrassie 6 and the development of Neandertal pubic morphology

Functional interpretations of the mediolateral elongation and superoinferior flattening of the superior pubic ramus of Neandertals require knowledge of its ontogeny. Metric comparisons between the La Ferrassie 6 Neandertal infant, aged 3-5 years, and a sample of modern infants reveal that the acetabulosymphyseal length of La Ferrassie 6, relative to femoral length and iliac breadth, falls at the limits of the range of variation of the modern infants, while the relative height of its superior pubic ramus is indistinguishable from that of the modern sample. It appears that acetabulosymphyseal elongation of the Neandertal pubis is a feature which is expressed quite early in ontogeny, well before puberty. Superoinferior flattening and ventral margin thinning of the superior ramus probably appear later in Neandertal ontogeny.     

Nasal morphology and the emergence of Homo erectus

Modern humans, among extant hominoids, possess a unique projecting, external nose whose basic structure is reflected in a series of skeletal features including nasal bone convexity, an internasal angle, lateral nasal aperture eversion, prominence and anterior positioning of the anterior nasal spine, an acute angle of the subnasal alveolar clivus, and an expansion of the breadth of the nasal bones relative to that of the piriform aperture. This anatomy appears with the emergence of Homo erectus ca. 1.6 million years ago. Although it undoubtedly evolved in the context of craniofacial and dental reduction during hominid evolution, it appears to have been primarily a response to the need for moisture conservation in an arid environment via turbulence enhancement and ambient cooling of expired air. Its appearance at this time in hominid evolution, in conjunction with the presence of a fatigue-resistant locomotor anatomy characteristic of archaic members of the genus Homo, indicates a shift to increasingly prolonged bouts of activity in open and arid environments.     

古生物学与INTERNET

简要介绍了正在迅速发展的国际互联网络及其在古生物学方面提供的信息资源和服务项目,对古生物学工作者了解世界同行的工作、促进交流都有益处。     

The “Pithecanthropus IV” diastemata: Malocclusion in a fossil man

The Homo erectus skull fragments collected by von Koenigswald in Java in 1939 and designated by him as Pithecanthropus IV have been a source of ongoing interest because of the unique precence of seemingly simian-like precanine diastemata evident in the restored maxilla. These interdental spaces have posed a paradox because similar gaps are absent in other pithecanthropine remains and in considerably older hominid fossils.I have tested the hypothesis that the skull IV diastemata represent a human occlusal variant; in this paper, I illustrate methods of differential occlusal analysis and describe the multiplicity of factors that may lead to superficially similar maxillary precanine diastemata. Results of analysis of skull IV characteristics suggest that the diastemata were caused by labial displacement of the maxillary incisors because of vertical collapse after loss of the posterior mandibular teeth.     

Brief communication: predatory bird damage to the Taung type-skull of Australopithecus africanus Dart 1925

In this issue of the Journal, McGraw et al. ([2006] Am. J. Phys. Anthropol. 000:00-00) present new data on the taphonomic signature of bone assemblages accumulated by crowned hawk eagles (Stephanoaetus coronatus), including characteristic talon damage to the inferior orbits of primates preyed upon by these birds. Reexamination of the Taung juvenile hominin specimen (the type specimen of Australopithecus africanus Dart 1925) reveals previously undescribed damage to the orbital floors that is nearly identical to that seen in the crania of monkeys preyed upon by crowned hawk eagles (as reported by McGraw et al., this issue). This new evidence, along with previously described aspects of the nonhominin bone assemblage from Taung and damage to the neurocranium of the hominin specimen itself, strongly supports the hypothesis that a bird of prey was an accumulating agent at Taung, and that the Taung child itself was the victim of a bird of prey.     

Incidence and patterning of dental enamel hypoplasia among the Neandertals

Dental enamel hypoplasia (DEH), as an indicator of nonspecific stress during development, provides an assessment of the relative morbidity of past human populations. An investigation of 669 Neandertal dental crowns yielded an overall DEH frequency of 36.0% by tooth (41.9% for permanent teeth; 3.9% for deciduous teeth) and about 75% by individual. These incidences place the Neandertals at the top of recent human ranges of variation in DEH frequencies, indicating high levels of stress during development. The paucity of deciduous tooth DEH and M1 DEH, combined with generally increasing levels of DEH through later calcifying teeth, suggests that the stress was primarily nutritional, beginning at weaning and continuing through adolescence. This supports paleontological and archeological interpretations implying significantly lower effectiveness for Neandertal foraging compared to that of modern humans.     

The synarcual cartilage of batoids with emphasis on the synarcual of Rajidae

Comparison of embryonic specimens with juvenile and mature specimens of other skates indicates that the relative developmental sequence of events is maintained among several taxa within larger clades. However, there is a fundamental difference between the pattern of chondrification and the pattern of calcification in skates. Early in ontogeny a short synarcual surrounds the first free vertebral centrum. Additional neural arch segments are incorporated from anterior to posterior and the relative length of the synarcual cartilage to total length of the body normalizes early. A secondary direction of chondrification, from ventral to dorsal, is also present. Juveniles and subadults show that synarcual calcification is relatively late compared to the calcification of other regions of the skeleton and proceeds from lateral to medial. Comparison with extinct taxa also indicates that there is a decrease in vertebral centrum involvement with the synarcual cartilage over the evolutionary history of the clade. Results from exploratory analyses of morphospace and taxonomy reveal that phylogeny explains part, but not all, of the data on the synarcual in Rajidae. There is evidence of individual and ontogenetic variation among all species of skates examined, however, phylogenetically informative variation prevails. Comparison with other batoids demonstrates a trend where the number of vertebral centra flanked by the synarcual cartilage decreases among more derived taxa indicating a high degree of convergent morphology among batoids with potential functional significance. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Mechanical advantages of the Neanderthal thumb in flexion: a test of an hypothesis

It has been proposed that the pollical phalangeal length proportions of the Neanderthals provided them with a greater mechanical advantage relative to recent humans for their pollical flexor muscles in power grips across the interphalangeal (IP) joint at the expense of the mechanical advantage of those pollical flexor muscles in precision grips at the finger tip. To test these related hypotheses, we compared the pollical load arm dimensions (phalanx lengths) to power arm dimensions (dorsopalmar articular heights) for the European and Near Eastern Neanderthals and for European and Amerindian samples of recent humans. It was found, initially, that the proximal articular height of the pollical distal phalanx is a poor predictor of the power arm at the IP articulation, even though the proximal articular height of the pollical proximal phalanx was an adequate indicator of the power arm size at the metacarpophalangeal (MCP) joint. In addition, differences in distal pollical ulnar deviation at the IP joint appeared to make little difference in the mechanical advantage comparisons. More importantly, the relative shortness of Neanderthal proximal pollical phalanges and the relative lengthening of their distal pollical phalanges was confirmed, and it was determined that, despite some minor differences in articular dimensions between Neanderthals and recent humans, these pollical phalangeal length contrasts translated into significant differences in mechanical advantages for the flexor muscles across the MCP and IP articulations.     

Neandertal capitate-metacarpal articular morphology

Neandertal capitate-metacarpal 2 and 3 articulations have been observed to differ in orientation and shape from those of more recent humans. To evaluate this, we tested for differences in capitate-metacarpal 2 (MC2) and MC2-capitate facet orientations and MC2 and MC3 robusticity indices, and for multivariate shape equivalence of the capitate-MC2/MC3 facets and the MC3 diaphysis and styloid process between samples of Neandertals and recent humans. Canonical discriminant functions of log size-and-shape and log shape transformed measurements were run on variables of the capitate-MC2 and MC3 facets, and these plus MC3 diaphysis and styloid process variables. The null hypothesis of shape equivalence is rejected for both variable sets. Modern human capitate-MC morphology results from nonallometric increases in distal capitate breadth and the projection of the MC3 styloid process, and reductions in MC2 facet height and MC3 facet breadth. These shape changes are associated with a significantly less parasagittal orientation of the capitate-MC2 facets in recent humans, but are only trivially correlated with MC 2 and 3 robusticity indices. The recent human capitate-MC 2 and 3 morphology may reflect a shift in habitual joint reaction forces from more axial to more oblique forces while maintaining similar pronation/supination of the MC2. However, the full behavioral implications of these contrasts remain unclear. Am J Phys Anthropol 103:219–233, 1997. © 1997 Wiley-Liss, Inc.     

古昆虫学研究的发展历程简介

古昆虫学研究始于200年前。此后,该学科不断发展,不断提高。依据研究方法及综合水平的不同,可将其发展历程划分为6个部分:朴素的萌芽和学科的诞生、基础分类研究、归纳总结研究、系统发育学研究、古环境古生态及古地理的研究、化石昆虫与其他物种相互作用的研究。文章简要介绍了上述各部分,并作了简评。     

The ecology of oligocene African anthropoidea

African anthropoids are first recorded in Early Oligocene deposits of the Fayum Province, Egypt. Six genera and nine species are recognized. Estimated body weights for these taxa are based on the regression equation log ₁₀(B) = 2.86log ₁₀(L) + 1.37, whereB is the bodyweight in grams, and Lis the M ₂ length in millimeters. The equation is derived from 106 species of living primates. Fayum species range in body weight from about 600 g (Apidium moustafai)to about 6000 g (Aegyptopithecus zeuxis).A similar range of body weight is found among extant Cebidae. The Fayum primates are larger than any extant insectivorous primates;this fact probably rules out a predominantly insectivorous diet. Extant frugivorous hominoids can be separated from folivorous hominoids on the basis of molar morphology. Folivorous apes (gorilla and siamang) have proportionately more shearing on their molars than do frugivorous species. Based on the hominoid analogy, the molar morphology of the Fayum species is consistent with a frugivorous diet. Parapithecus grangeristands apart from other Fayum species in having better developed molar shearing, possibly indicating that it had more fiber in its diet. Terrestrial species of Old World monkeys tend to have significantly higher molar crowns than do more arboreal species. This difference may relate to an increased amount of grit in the diet of the more terrestrial species, selecting for greater resistance to wear. Oligocene primates have molar crown heights consistent with a primarily arboreal mode of existence. However, the particularly high molar crowns of Parapithecus grangerisuggest that this species may have foraged on the ground to a considerable degree. Other evidence is advanced suggesting that Apidiummay have had a diurnal activity pattern.     

The remains of a fossil Soft-shelled Turtle (Trionyx) from the Bayraktepe area (Turkey)

Abstract

The remains of the pectoral girdle (scapulocoracoid) and carapace of Trionyx sp. which were found in the Upper Miocene sediments of Bayraktepe are described and discussed.     

Hominid taphonomy: Transport of human skeletal parts in an artificial fluviatile environment

Flume experiments demonstrate that human skeletal parts sort into lag and transportable groups in a current flow of 31 cm/sec. Orientations, rates and types of movement, and stable positions are recorded. Density of a skeletal part is correlated with the average rate of movement, whereas wet weight in air, weight in water, and volume are not. Shape is an important but unquantifiable factor. Complete crania are the fastest moving elements; individual cranial fragments are in the lag group. Omo fluviatile deposits show a preponderance of hominid lag elements, whereas Olduvai and East Rudolf perilacustrine deposits present a mixture of transportable and lag elements.     

Early ontogeny of the human femoral bicondylar angle

The presence of a femoral bicondylar angle consistently and significantly greater than 0° has been a hallmark of hominid bipedality, but its pattern of development has not been documented. We have therefore compiled cross-sectional data on the development of the articular bicondylar angle for a clinical sample of modern humans and of the metaphyseal bicondylar angle for two Recent human skeletal samples, one predominantly European in origin and the other Amerindian. All three samples exhibit a pattern of a bicondylar angle of 0° at birth and then a steady average increase in the angle from late in the first year postnatal, through infancy, and into the juvenile years. The two skeletal samples reach low adult values by approximately 4 years postnatal, whereas the clinical sample with a lowered activity level appears to attain consistent adult values slightly later (approximately 6 years postnatal). In addition, two modern human individuals, one nonambulatory and the other minimally ambulatory, show no and little development, respectively, of a bicondylar angle. These data, in conjunction with clinical and experimental observations on the potential and form of angular changes during epiphyseal growth, establish a high degree of potential for plasticity in the development of the human bicondylar angle and the direct association of a bipedal locomotion and (especially) posture with the developmental emergence of a human femoral bicondylar angle. © 1994 Wiley-Liss, Inc.     

The Species Concept as a Cognitive Tool for Biological Anthropology

Taxonomy is caught between the search for the “perfect” theory and an elusive biological variability. The lack of major advances in issues related to how “species” and other taxonomic categories are defined suggests that perhaps we should avoid excessively rigid formalism in this regard. The risk is a separation between elegant but useless theories and confusing applications of the taxonomic tools. Communication is one of the main functions of taxonomy, and stability one of the main parameters that taxonomy users should be sensitive to. An excess of stability may generate anachronistic consequences while continuous revisions may make the tool of taxonomy scarcely practical. The current tendency pushes toward more and more fragmentation of biologically valid taxa. While taxonomy specialists enjoy such challenges, many taxonomy users feel a bit nervous and discouraged when trying to use a tool that is constantly changing. Debates over taxonomy would seem particularly unrewarding for fields with limited samples and scarce biological diversity, such as palaeoanthropology. In this context, where the information available is rarely sufficient to supply consistent taxonomical evidence, there are frequently excessive efforts to create debate on species separations. The risk is that we maintain the debate on a purely theoretical level, or else we distrust a reliable use of taxonomy. A compromise (and recommended) choice between these two extremes would be to rely on shared and reasonable interpretations of homogeneous evolutionary units, without diving into fine‐grained issues that will remain, however, unresolved. Taxonomy should be a tool, not the goal, of the evolutionary biologist. Our mind needs discrete and recognizable objects to structure our perception of reality. There is no reason to expect that nature works the same way. Am. J. Primatol. 75:10‐15, 2013. © 2012 Wiley Periodicals, Inc.     

Olduvai Hominid 7 trapezial metacarpal 1 articular morphology: contrasts with recent humans

A consideration of the metacarpal 1 articulation of the Olduvai Hominid 7 trapezium shows that, although it is generally similar to those of recent humans, it is considerably flatter radioulnarly and dorsopalmarly than those of modern humans and similar in its degree of dorsopalmar flattening to those of Upper Pleistocene late archaic humans. Even though this flattening may have slightly limited flexion-extension at the pollical carpometacarpal joint, it is most likely related to the apparently elevated levels of axial joint reaction force through the thumbs of archaic members of the genus Homo. It also documents the continuation of human carpometacarpal articular evolution through the Pleistocene.     

Particulate versus integrated evolution of the upper body in late pleistocene humans: A test of two models

Evolutionary biologists are largely polarized in their approaches to integrating microevolutionary and macroevolutionary processes. Neo-Darwinians typically seek to identify population-level selective and genetic processes that culminate in macroevolutionary events. Epigeneticists and structuralists, on the other hand, emphasize developmental constraints on the action of natural selection, and highlight the role of epigenetic shifts in producing evolutionary change in morphology. Accordingly, the ways in which these paradigms view and address morphological contrasts between classes of related organisms differ. These paradigms, although seldomly explicitly stated, emerge in paleoanthropology as well. Considerations of postcranial morphological contrasts between archaic and modern humans typically fall into one of two broad interpretive models. The first derives from the neo-Darwinian perspective and holds that evolution in the postcranial skeleton was largely mosaic (operating in a particulate manner), and that temporal change in specific traits informs us about behavioral shifts or genetic evolution affecting isolated anatomical regions (i.e., adaptive behavioral inferences can be made from comparative studies of individual trait complexes). The alternative model follows from the epigeneticist paradigm and sees change in specific postcranial traits as correlated responses to change in overall body form (involving shifts in regulation of skeletal growth, or selective and developmental responses to broad adaptive shifts). By this view, integration of functional systems both constrains and directs evolution of various traits, and morphological contrasts inform us about overall change in body form related to change in such things as overall growth patterns, climatic adaptation, and technological dependency. These models were tested by confirmatory factor analysis using measures of upper body form and upper limb morphological traits in Eurasian Neandertal and early modern fossils and recent human samples. Results indicate (1) a model of morphological integration fits the data better than a model of no integration, but (2) this integration accounts for less than half of the variance in upper limb traits, suggesting a high degree of tolerance for particulate evolution in the context of an integrated upper body plan. Significant relationships were detected between joint shapes and body size, between humeral shaft shape and body size and chest shape, and between measures of biomechanical efficiency and robusticity. The observed morphological differences between late archaic and early modern humans reflect particulate evolution in the context of constraints imposed by genetic and morphological integration. While particulate approaches to interpreting the fossil record appear to be justified, attention must also be paid to delineating the nature and extent of morphological integration and its role in both constraining and producing observed patterns of variation between groups. Confirmatory factor analysis provides a means of examining trait covariance matrices, and serves as a useful method of identifying patterns of integration in morphology. © 1996 Wiley-Liss, Inc.