A hominid mandible from East Rudolf, Kenya

A hominid mandible, KNM-ER 1482, is described. Provisionally it has not been assigned to any existing species or genus. However, after detailed anatomical and comparative studies have been carried out, its taxonomic status will be reviewed.     

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.     

Preliminary observations on the BK 8518 mandible from Baringo, Kenya

A newly discovered adult hominid mandible (BK 8518) from Baringo, Kenya, is described and assessed. The corpus, many of the tooth crowns, and most of the left ascending ramus are preserved. The teeth are heavily and asymmetrically worn. Compared with BK 67 (the 1966 mandible) the body of BK 8518 is more robust; the internal symphyseal buttressing is more pronounced; the M3s have seven cusps and exceed the M2s in size. There are no compelling reasons, however, to attribute the two mandibles to different taxa and, in view of the lack of any comprehensive taxonomic diagnosis for Homo erectus, "erectus-like," and habiline mandibular remains, the new specimen is also best regarded as Homo sp. indet. (aff. erectus).     

Computed tomography and enamel thickness of maxillary molars of Plio-Pleistocene hominids from Sterkfontein, Swartkrans, and Kromdraai (South Africa): An exploratory study.

This paper is one in a series which explores the possibility of using the non-destructive CT technique to identify patterns in tooth enamel distribution and structure of hominid molars from Plio-Pleistocene sites in South Africa, notably Swartkrans, Sterkfontein, and Kromdraai. Whereas previous investigators have emphasised gross differences in absolute and relative or average enamel thickness between hominid taxa, the present study highlights differences in enamel thickness over functionally significant regions of the crown. Differences in the distribution of enamel in A. robustus, A. africanus, and Homo sp. are identified through the use of bivariate and multivariate analyses, and are interpreted in terms of dietary regimes.     

Faunal remains from Porc-Epic: paleoecological and zooarchaeological investigations from a Middle Stone Age site in southeastern Ethiopia

The Middle Stone Age (MSA) sediments of Porc-Epic Cave near Dire Dawa, Ethiopia, have produced a large assemblage of archaeofaunal remains dating to the later periods of the Late Pleistocene. As one of the few MSA faunal assemblages from East Africa subject to detailed analysis, it provides rare insight into the foraging behavior of the early modern humans in this region. The MSA fauna include taxa that were not historically present in the area, with the occurrence of reduncines and alcelaphines indicating widespread grasslands and proximity to a perennial source of water. The faunal analysis examined several lines of evidence, including breakage patterns, surface modification, and skeletal-element representation. By incorporating comparisons with multiple actualistic data sets, the analysis of the assemblage demonstrates that, while the influence of carnivores and other biotic agents was evident, the faunal remains were accumulated primarily by hominid activity. The skeletal-element representation at Porc-Epic includes an abundance of high utility bones, in contrast to the predominance of "head-and-foot" elements documented at other MSA and Middle Paleolithic (MP) sites. The MSA occupants of Porc-Epic effectively exploited a wide range of prey with more emphasis on small- and medium-sized mammals.     

Microscopic criteria for the determination of directionality of cutmarks on bone

Shipman and Rose (1983) have recently attracted attention to the fact that the determination of directionality of cutmarks could possibly provide additional evidence for interpretation of early hominid butchering practices and handedness. They found no criteria of directionality, however. We have previously recognized directionality in cut dental tissues and more recently in bone, and so we undertook a study of over 200 experimentally produced cutmarks on bovine bone by scanning electron microscopy. Three criteria of directionality were observed: bone smears, oblique faulting, and oblique chipping. In our analysis we considered properties of bone as a relevant variable in the microscopic appearance of cutmarks, which has also led to the new finding that not all marks made by a single tool under similar conditions are the same. We observed that bone smears occurred in most specimens, relatively low density forming bone surfaces facilitated oblique fault production, whereas oblique chipping frequently occurred in plexiform bone tissue common to growing artiodactyls. In this study, handedness of the operator could be determined from cutmarks, but much further experimental work will be required in order to detail the criteria.     

Population characteristics of extinct hominid endocranial volume

Distribution and variation statistics of hominid endocranial volume (ECV) have been investigated. Within the interpretative constraints imposed by (very) small sample sizes, the requirements for normality are met, as are those for heteroscedasticity. A significant difference in means can be demonstrated for only two comparisons. With one exception, overall distribution characteristics differ significantly in pairwise comparisons between taxa. The coefficient of variation of ECV that characterizes a group composed of all Plio-Pleistocene gracile hominids does not support a single polytypic species interpretation of this assemblage. Significant differences in the coefficient of variation exist between all possible pairs of taxa with the exception of Homo habilis and Homo erectus.     

Taphonomic bias, taxonomic bias and historical non-equivalence of faunal structure in early hominin localities

Environmental interpretation of fossil assemblages requires an accurate reconstruction of the community from which the assemblage was derived, which in turn depends on the quality of a comparative model usually based on the study of modern equivalents. The degree of inaccuracy introduced by taphonomic and other types of bias is often difficult to assess and the suitability of comparative models has rarely been addressed in this light. Here we apply a recently developed method to assess the bias present in a range of key hominin bearing localities from the Neogene of East and South Africa. The ecological structure of several of the investigated faunas can be shown to depart substantially from that of a comprehensive range of modern comparative faunas. Bias, where present, affects primarily the small mammals, which tend to be under-represented, and the large primary consumers, which tend to be over-represented. This has potentially significant implications for past and future palaeoecological reconstruction of these localities as numerous methods that are currently in use rely extensively on either the small mammals or the large primary consumers, and in particular the bovids. Understanding the nature of the bias, when present, will go some way towards improving the quality of environmental reconstructions.     

Studies on the condition and structure of bone of the Saldanha fossil cranium.

The external surface of the Saldanha cranium shows extensive exfoliation and cracking. In a few places remnants of the probable original bone surfaces can be observed. These are orange-brown in color, contrasting with the nearly white color of exposed deeper layers, and are subdivided into small segments with pits in their centers. Causes of the color differences are uncertain but merit investigation. The surface cracking and exfoliation probably result from weathering before fossilization. This conclusion is based on the observation that the endocranial surfaces show no such effects, despite the scattering of the cranial fragments at the time of discovery. A depressed fracture in the frontal bone indicates a heavy blow at or shortly after the time of death. This blow probably created some of the fragments, but there are also incomplete fracture cracks which may have resulted from the blow. Unresolved taphonomic problems include the manner in which the cranium held together after decay of soft tissues allowed weathering, and the manner in which the fragments were subsequently scattered. Chips from the cranial vault indicate that the outer table was very thick, tending to support recent proposals that the specimen and assoicated fauna and tools are from a considerably earlier time period than originally believed. The surface damage to the brow ridges gives information on the structure of deeper layers. These are lacking orientation, supporting the hypothesis that hominid brow ridges are not primarily a response to masticatory forces, but may afford protection for the eyes.     

Long-distance carcass transport at Olduvai Gorge? A quantitative examination of Bed I skeletal element abundances

Relative abundances of skeletal elements at Plio-Pleistocene archaeological sites have long been interpreted to represent selective transport of portions of large prey. Models from optimal foraging theory suggest that the degree of carcass transport selectivity reflects transport constraints, particularly transport distance. A quantitative analysis of skeletal element abundances in five bone assemblages from Bed I, Olduvai Gorge, indicates that within the subset of elements most likely to resist attritional processes, there is no evidence for preferential transport of small or large mammals. The results suggest relatively low carcass transport costs and are most consistent with site formation models favoring short-distance carcass transport. The data are also consistent with the possibility that hominins were not responsible for transporting bones at some sites. Several Bed I assemblages, with the exception of FLK-Zinjanthropus, lack evidence of a functional relationship between flaked stone artifacts and the faunal remains, such as cut-marks or percussion-marks on bone. In conjunction with the skeletal part data, this suggests that hominin involvement with the bone assemblages was minimal at all sites but FLK-Zinjanthropus. The patterning at Bed I contrasts strongly with Middle Stone Age and Middle Paleolithic assemblages, which provide clear evidence for selective transport, suggesting higher transport costs and longer transport distances.     

New evidence of the genus homo from East Rudolf, Kenya (IV)

Four partial mandibles and three isolated teeth of Homo from East Rudolf, Kenya, are described. They represent only part of the 1972 fossil collection that has been assigned to Homo; results of detailed studies of this material will be published in a monograph.     

Four-million-year-Old hominids from East Lake Turkana,Kenya

A piece of mandible and several isolated teeth are reported from fluviatile sediments older than 4 million years at East Lake Turkana. They most closely resemble hominids from Laetoli, Tanzania and Hadar, Ethiopia which have been assigned to Australopithecus afarensis. © 1994 Wiley-Liss, Inc.     

Microtaphonomy of bioclasts and paleoecology of microencrusters from Upper Jurassic spongiolithic limestones (External Prebetic,Southern Spain)

Microencrusters and microtaphonomic features of the Oxfordian spongiolithic limestones of the External Prebetic were studied using thin-section analysis. The spongiolithic limestone is a bioclastic-rich packstone with common echinoderm, mollusc and brachiopod remains. The bioclasts show a high fragmentation index and frequent microborings. The encrustation index (E _i) is higher for fragments of serpulids, ammonoids and bivalves, and increases with the initial grain-size of bioclasts. The main microencrusters consist of benthic microbial communities (BMC) and nubeculariids, as well as subordinate calcareous and siliceous agglutinated foraminifera, serpulids and bryozoans. BMC are usually the first colonizers, and encrusting foraminifera mainly appear on bioclasts larger than 2 mm. BMC dominate in well-developed encrustations on upward facing surfaces of larger bioclasts that are also colonized by foraminifera (nubeculariids and Subdelloidina). Bullopora, serpulids and bryozoans are more common on lower surfaces. The fact that the values of encrustation index, encrustation thickness and diversity of the microencrusters increase with the size of bioclasts is related to a higher stability and exposure time of the available bioclastic substrate. The microencruster distribution on upper and lower surfaces of large bioclasts may be related to photic control, space competition and/or predation avoidance.     

Length estimate for KNM-ER 736, a hominid femur from the lower pleistocene of East Africa

Our knowledge concerning stature in earlyHomo is scanty. In this paper, based on comparison with the fossil femur KNM-ER 999, an estimate of 482 mm femur length is derived for KNM-ER 736, the latter dating from the Lower Pleistocene. From comparison with other fossil and modern femora, KNM-ER 736 appears to be the longest hominid femur so far recovered from a site of Early Pleistocene age. Moreover, the estimated femur length is higher than the published mean values of most modern populations. Provided that trunk and head proportions were not radically different from modernH. sapiens, the finding would suggest that a stature similar to that of modern man was already reached by East AfricanHomo as early as about 1.6 Myr before present.     

The succulent flora of South Africa and Namibia: representation and distribution

Abstract

Taxonomic representation and regional distribution patterns of taxa, life forms, and defence mechanisms of the succulent flora of South Africa and Namibia are quantified and discussed in relation to physical and biotic factors. Habitats are investigated and for each region centres of succulent species richness are pointed out.