Glenn C. Conroy

Problems of body-weight estimation in fossil primates

Body-weight estimates of fossil primates are commonly used to infer many important aspects of primate paleobiology, including diet, ecology, and relative encephalization. It is important to examine carefully the methodologies and problems associated with such estimates and the degree to which one can have confidence in them. New regression equations for predicting body weight in fossil primates are given which provide body-weight estimates for most nonhominid primate species in the fossil record. The consequences of using different subgroups (evolutionary “grades”) of primate species to estimate fossil-primate body weights are explored and the implications of these results for interpreting the primate fossil record are discussed. All species (fossil and extant) were separated into the following “grades”: prosimian grade, monkey grade, ape grade, anthropoid grade, and all-primates grade. Regression equations relating lower molar size to body weight for each of these grades were then calculated. In addition, a female-anthropoid grade regression was also calculated for predicting body weight infernales of extinct, sexually dimorphic anthropoid species. These equations were then used to generate the fossil-primate body weights. In many instances, the predicted fossil-primate body weights differ substantially from previous estimates.

New Fossil Platyrrhines from Santa Cruz Province, Argentina

New platyrrhine fossils have been recovered from early Miocene deposits near the Pinturas River in Santa Cruz Province, Argentina. Soriacebus ameghinorum is a saki-sized monkey with

Endocranial capacity in Sts 71 (Australopithecus africanus) by three‐dimensional computed tomography

In a recent report on early hominid endocranial capacity, it was predicted that future studies would show that: (1) “several key early hominid endocranial estimates may be inflated”; (2) “current views on the tempo and mode of early hominid brain evolution may need reevaluation”; and (3) endocranial capacity in one of these, Sts 71, was “probably closer to 370 cm3, very near the mean value for female chimpanzees, and not the currently accepted 428 cm3” (Conroy et al., Science, 1998 ; 280: 1730–1731; Falk, Science 1998 ; 20:1714). Subsequent studies tend to support the first two predictions, but not the third (Culotta, Science, 1999 ; 284: 1109; Falk, Am. J. Phys. Anthropol. Suppl., 1999 ; 28: 126; Falk et al., J. Hum. Evol. [ in press ]). Here we detail the reasons for thinking the currently accepted endocranial value for Sts 71 is probably correct by providing the first quantitative details of endocranial reconstruction in Sts 71 using three‐dimensional computed tomography. Relative brain expansion in the hominid lineage started some half‐million years before the earliest appearance of the genus Homo, possibly coincident with enhanced tool‐making skills and carnivory. Anat Rec 258:391–396, 2000.

Google Earth, GIS, and the Great Divide: A new and simple method for sharing paleontological data

Introduction The ease, efficiency, and speed of data communication and analyses are paramount to, and characteristic of, any mature science. GIS is an extraordinarily powerful tool for many aspects of (geo)spatial analyses (Longley et al., 2001), but while used routinely to solve complex spatial analyses problems in many disciplines, its adoption within paleontology has been lagging (Conroy, 2006). Part of the problem is that (a) GIS software is expensive (usually prohibitively so to the individual paleontological researcher) and (b) very few paleontologists are trained in its use. Here we show how paleontological data can be easily displayed and communicated in ways never before possible by combining Google Earth and Geographic Information Systems (GIS). Using paleontological field data, we demonstrate several examples that go far beyond the novelty of simply “find my house” that many Google Earth users are currently familiar with. Specifically, we show how GIS map layers of paleontological interest, including their associated attribute tables (e.g., field catalog data), can be freely and easily transmitted to anyone with Internet access and familiarity with Google Earth. Data organized in GIS layers can be exported to the keyhole mark-up language native to Google Earth (KML/KMZ), transmitted to colleagues (who may have no knowledge of or access to GIS) as an email attachment, and then simply “dragged and dropped” by the recipient onto their own desktop Google Earth display, where the map layers appear “draped” over the Google Earth landscape. The recipient has access to all the graphics and attributes of each map layer that has been exported from GIS as well as to all Google Earth tools [e.g., ability to adjust map layer transparencies, labeling, longitude/latitude (or UTM determinations), spatial measurements, and “tilting” of landscapes for enhanced 3D views]. These tools are often sufficient to allow the non-GIS user to obtain specific information of interest from the data.

Permanent tooth calcification in chimpanzees (Pan troglodytes): Patterns and polymorphisms

Tooth calcification is an important developmental marker for use in constructing models for early hominid life history, particularly for its application to the fossil record. As chimpanzees are commonly utilized in interspecific comparisons in such research, this study aims to improve available baseline data for tooth calcification patterns in chimpanzees (Pan troglodytes), and to quantify basic patterns and polymorphisms. We present an analysis of developmental patterns for the left mandibular dentition (I1-M3) based on intraoral radiographs obtained from a cross-sectional sample of chimpanzees (58 males, 60 females) housed at LEMSIP (NYU Medical Center) and Yerkes (Emory University). No significant differences with previous descriptions of the basic sequences of tooth calcification in chimpanzees were found, but variation in such patterns was documented for the first time. In the overall sequence, polymorphisms between the canine and the group (M2 P4 P3) reached significant levels. This is due to the relative delay in canine crown formation compared to other teeth. Differences in the basic sequence between males and females were recorded, but are due to minor shifts in the percentages of occurrence for polymorphic sequences which are common to both genders. Perhaps our most important findings are that a) different polymorphic sequences occur in tooth calcification and tooth emergence in chimpanzees, and b) developmental relationships among teeth fluctuate throughout tooth calcification. Thus, characterizations of dental developmental patterns based on particular stages of development cannot necessarily be extrapolated to other stages without supporting data.

Cross‐sectional geometric properties of the Otavipithecus mandible

Cross-sectional geometric properties of the postcanine mandibular corpus are determined for the only known specimen of Otavipithecus namibiensis, a middle Miocene hominoid from southern Africa. It is shown that Otavipithecus is unique in that several important mechanical properties of its mandible, including maximum and minimum moments of inertia and distribution of cortical bone, differ from patterns seen in both extant hominoids and the early hominids Australopithecus africanus and Australopithecus (Paranthropus) robustus. This is particularly apparent in the mechanical design of the posterior portion of the mandibular corpus for resisting increased torsional and transverse bending moments. Cortical index values at the level of M2 also reveal that both Otavipithecus and A. africanus are similarly designed to resist increased masticatory loads with relatively less cortical bone area, a highly efficient mechanical design.

The Anomalous Archaic Homo Femur From Berg Aukas, Namibia: A Biomechanical Assessment

The probably Middle Pleistocene human femur from Berg Aukas, Namibia, when oriented anatomically and analyzed biomechanically, presents an unusual combination of morphological features compared to other Pleistocene Homo femora. Its midshaft diaphyseal shape is similar to most other archaic Homo, but its subtrochanteric shape aligns it most closely with earlier equatorial Homo femora. It has an unusually low neck shaft angle. Its relative femoral head size is matched only by Neandertals with stocky hyperarctic body proportions. Its diaphyseal robusticity is modest for a Neandertal, but reasonable compared to equatorial archaic Homo femora. Its gluteal tuberosity is relatively small. Given its derivation from a warm climatic region, it is best interpreted as having had relatively linear body proportions (affecting proximal diaphyseal proportions, shaft robusticity, and gluteal tuberosity size) combined with an elevated level of lower limb loading during development (affecting femoral head size and neck shaft angle).

Non-metric features in the ulna of Aegyptopithecus, Alouatta, Ateles, and Lagothrix.

A comparison of the non-metric features of the ulnar fragment (YPM 23940) referred to Aegyptopithecus zeuxis with those in the same bone of Alouatta, Ateles, and Lagothrix -- the three living taxa whose ulnae most closely resemble that of the fossil -- reveals that the closest similarities of the fragment are with the ulna of Alouatta.

Brief communication: new primate remains from the Miocene of Namibia, southern Africa.

Miocene primates from southern Africa are extremely rare. For this reason we wish to place on record several interesting new fossil primate specimens recently recovered from the Miocene sites of Berg Aukas and Harasib in the Otavi Mountain region of northern Namibia. The new finds consist of a virtually complete atlas vertebra from Berg Aukas attributable to the hominoid Otavipithecus namibiensis and two teeth and four postcranial fragments from Harasib referrable to Cercopithecoidea. The atlas vertebra exhibits anatomical characteristics intermediate between those of modern cercopithecoids and hominoids which may be indicative of a transition from pronograde to orthograde postures. The cercopithecoid remains show that the earliest Old World monkeys known from southern Africa were small, approximately the size of vervet monkeys. These new specimens are important because they provide the first evidence relating to possible positional behaviors of Otavipithecus and the earliest fossil record of cercopithecoids from southern Africa.

Earliest Known Procaviid Hyracoid from the Late Miocene of Namibia

Despite the great diversity of known fossil hyracoids that belong to the archaic family Pliohyracidae, practically nothing has been unravelled about the origin and diversification of the modern family Procaviidae (containing four genera of Pliocene to Recent age). A new species of procaviid hyrax is reported from Namibian cave breccias dating to the earlier part of the late Miocene. The new species is represented by dental, postcranial, and fragmentary cranial specimens. Despite its 1.0 x 10 7 -year age, the new hyracoid cannot be generically distinguished from the modern genus Heterohyrax. The new species differs from extant H. brucei in its less molarized anterior premolars, and its molar cusps that are slightly more inflated basally. The possible relevance of the new fossil for the origin and radiation of the family Procaviidae is discussed.