A new origin for the maxillary jaw

One conserved feature of craniofacial development is that the first pharyngeal arch has two components, the maxillary and mandibular, which then form the upper and lower jaws, respectively. However, until now, there have been no tests of whether the maxillary cells originate entirely within the first pharyngeal arch or whether they originate in a separate condensation, cranial to the first arch. We therefore constructed a fate map of the pharyngeal arches and environs with a series of dye injections into stage 13-17 chicken embryos. We found that from the earliest stage examined, the major contribution to the maxillary bud is from post-optic mesenchyme with a relatively minor contribution from the maxillo-mandibular cleft. Cells labeled within the first pharyngeal arch contributed exclusively to the mandibular prominence. Gene expression data showed that there were different molecular codes for the cranial and caudal maxillary prominence. Two of the genes examined, Rarbeta (retinoic acid receptor beta) and Bmp4 (bone morphogenetic protein) were expressed in the post-optic mesenchyme and epithelium prior to formation of the maxillary prominence and then were restricted to the cranial half of the maxillary prominence. In order to determine the derivatives of the maxillary prominence, we performed focal injections of CM-DiI into the stage 24 maxillary prominence. Labeled cells contributed to the maxillary, palatine, and jugal bones, but not the other elements of the upper beak, the premaxilla and prenasal cartilage. We also determined that the cranial cells give rise to more distal parts of the upper beak, whereas caudal cells form proximal structures. Grafts of stage 24 maxillary prominences were also analyzed to determine skeletal derivatives and these results concurred with the DiI maps. These early and later fate maps indicate that the maxillary prominence and its skeletal derivatives are not derived from the first pharyngeal arch but rather from a separate maxillary condensation that occurs between the eye and the maxillo-mandibular cleft. These data also suggest that during evolution, recession of the first pharyngeal arch-derived palatoquadrate cartilage to a more proximal position gave way to the bony upper jaw of amniotes.     

Meat-eating by early hominids at the FLK 22Zinjanthropussite, Olduvai Gorge (Tanzania): an experimental approach using cut-mark data

The meat-eating behavior of Plio-Pleistocene hominids, responsible for the bone accumulations at the earliest archaeological sites, is still a hotly-debated issue in paleoanthropology. In particular, meat-eating and bone marrow consumption are often presented as either complementary or opposing strategies of carcass exploitation. The presence of cut marks on fossil archeofauna is a potential source of information that has not been consistently used as evidence of carcass consumption by hominids. Some authors interpret cut marks as the result of hominids manipulating meat-bearing bones, while others argue that they can also be the result of hominids extracting marginal scraps of carcass flesh that have survived carnivores’ initial consumption. In this study, a referential framework concerning the interpretation of cut marks is presented, based on a set of experiments conducted by the author. It is suggested, according to these experiments and data drawn from the FLK “Zinj” site, that hominids processed meat-bearing bones (on which flesh was abundant) rather than defleshed carcasses from felid kills.     

Mandible bone resorption as determined from panoramic radiographs in edentulous male individuals aged 25–80 years

Routine panoramic radiographs of 173 healthy edentulous males, aged 25–80 years, were measured for estimated bone loss using the Wical and Swoope (1974) technique. Results using this simple technique were comparable to other studies using more sophisticated methods but did not require exposure to additional radiation. Mean ratios of height of mandible (indicative of mandibular bone loss) decreased both with age of subject and with time after extraction. Efforts should be made to determine the usefulness of such archival radiographic films for a variety of studies.     

Taphonomic signature of golden eagles (Aquila chrysaetos) on bone prey remains

Abstract

The golden eagle (Aquila chrysaetos) is one of the most important birds of prey in the Northern Hemisphere. This raptor is used to building large nests in high cliffs to which they return for several breeding years accumulating important amounts of their prey skeletal remains. This makes the golden eagle one of the major predators able to accumulate faunal remains in archaeological sites. Despite this fact, the taphonomic signature of golden eagles has not been properly characterized. Here we present the analysis of ingested and non-ingested faunal remains predated and accumulated by this raptor in two different nesting areas from the Iberian Peninsula. Results show how the faunal taxonomic record may vary depending on the ecological zone. Leporids and terrestrial carnivores are the best represented. The observed anatomical representation, breakage and bone surface modification patterns are discussed for different taxa. The taphonomic pattern varies depending on the type of prey and the origin of skeletal materials (non-ingested vs. pellets). Finally, after comparing our results with marks left by other predators, several characteristic features are noted to recognise golden eagles as agents of animal bones accumulations in the fossil record.     

雅罗鱼亚科咽骨及咽齿的研究

本文根据对雅罗鱼亚科咽骨及咽齿的研究,将其咽骨分为三种类型。研究结果表明,本亚科咽骨形态及咽齿结构表现有与食性高度适应的现象。本亚科的咽齿有圆锥型,斜齿面型及特化型,这是对三种不同食性适应的结果。依据咽骨、咽齿的结构特点,试拟了雅罗鱼亚科属的检索。     

Lead levels in ancient and contemporary Japanese bones

During the past few centuries, lead production, consumption and emissions, to our total environment have increased remarkably. We have determined the concentrations of lead in 41 well-preserved ancient and 11 contemporary rib bones of a mature age (40–60 y), with a view to historically evaluating lead exposure in humans. The oldest Japanese bones (1000–300b.c.) were found to contain a mean of 0.58 μg Pb/g dry wt and a mean molar ratio of lead to calcium of 0.6×10⁻⁶, compared with 4.7–5.2×10⁻⁶ in the bones of the Edo era (1600–1867a.d.) and contemporary residents in Japan. The mean molar ratios of female bones were always higher than those of male bones for each era. From this fact we may assume that facial cosmetics were one of the main routes of lead exposure among the ancient Japanese, especially those who lived during the Edo era.     

Secretion by the mandibular gland of the red kangaroo (Macropus rufus) during isoprenaline infusion

Summary Intracarotid infusion of isoprenaline, either alone or in combination with acetylcholine infusion was used to stimulate salivation by the mandibular glands of anaesthetized red kangaroos. Isoprenaline alone (0.20–1.25 mol·kg^–1·min^–1) elicited flow rates ranging from 0.014 to 0.239 ml·min^–1 (1.21–28.1 l·g gland^–1·min^–1). Salivary concentrations of sodium, chloride, phosphate and urea were negatively correlated with flow, whereas potassium, calcium, magnesium, hydrogen ion, bicarbonate, protein, and osmolality were poorly correlated with flow. Relative to cholinergic saliva produced at equivalent flow rates, isoprenaline-evoked saliva had higher osmolality, saliva/plasma urea ratios and concentrations of protein, potassium, magnesium, bicarbonate, and phosphate, but lower sodium, chloride and hydrogen ion levels. At a steady salivary flow (0.5 ml·min^–1), superimposition of isoprenaline infusion (0.15 mol·kg^–1·min^–1) on a pre-existing acetylcholine infusion reduced the rate of acetylcholine administration necessary to maintain flow, increased osmolality and the concentrations of protein, urea, potassium, calcium, magnesium, bicarbonate and phosphate and decreased sodium, chloride and hydrogen ion in the saliva. Salivary amylase activity was low and highly variable and the amylase activity/protein ratio fell substantially during isoprenaline stimulation. These results support the conclusion that the enzyme is of extrinsic origin. The response of the kangaroo mandibular gland to isoprenaline stimulation was very similar to that reported for rat mandibular gland, suggesting that the same ion transport phenomena underlie mandibular secretion in both species and probably in therian mammals generally.     

Novel mandibular gland volatiles from Apterostigma ants

The fungus-farming ants are a well-studied evolutionary radiation within the subfamily Myrmicinae that associate with a web of symbionts that span kingdoms. Members of the Apterostigma pilosum species group cultivate unique basidiomycete fungi belonging to the coral-mushroom family Pterulaceae, a family of fungi that is distantly related to the Agaricaceae (Leucoagaricus and Leucocoprinus) fungi grown by most fungus-farmers including other members in the genus Apterostigma (A. auriculatum group and A. megacephala). A chemical analysis using gas chromatography–mass spectroscopy of the mandibular gland volatiles of two species – A. dentigerum and A. manni – revealed the presence of an extraordinary diversity of natural products. Many of these compounds are new to Arthropoda, such as a homologous series of 3-methyl-2-alkanones, 2-methyl-2-alkenals, and 1-phenyl-2-propanone in A. dentigerum and 1-phenyl-2-propanol in A. manni. These results identify a remarkable divergence of compounds across the fungus-growing ants and other members in Myrmicinae. Functions of these natural products are proposed and discussed.     

Development of hind limb bones in chicken embryos under altered temperature and humidity conditions

The data on growth and development of hind limb bones in chicken embryos under normal (standard) and altered incubation conditions are presented.     

Relationships between lengths of long bones among recent Americans and Early Medieval Alamannic Germans

Relationships between lengths of long bones in early medieval Alamanns and in recent white Americans do not differ significantly. Lacking evidence of any differences between the contribution of trunk length to stature in the two samples, formulas for estimating stature based on relationships of bone lengths to stature in an American sample thus appear applicable to the Alamannic material.