A new method for assessing the sex of fragmentary skeletal remains: femoral shaft circumference

A simple discriminant function using midshaft femoral circumference for the determination of sex has been tested with 114 skeletons from the Libben Site, Ontario County, Ohio. The results have been shown to be 85% consistent with other, accepted means of determining sex. Femur circumference an be an aid to the sexual identification of poorly preserved and fragmentary skeletal remains.     

A critical evaluation of the relationship between the presynaptic network,synaptic vesicles and dense projections in central synapses

Summary Synapses of the oculomotor nucleus of Echidna have been examined ultrastructurally with the aim of integrating data obtained from osmicated and nonosmicated PTA stained material. Particular emphasis has been laid on the relationship between the synaptic vesicles of the osmicated material and the presynaptic network and vesicular grid of the PTA material. This relationship has been explored qualitatively by examining osmicated material of varying qualities of fixation. Such material contains dense projections in addition to synaptic vesicles, and various vesicular network appearances. A variety of measurement techniques have shown that the PTA network is characterised by reticular strands, spaces, and regular hexagonal units smaller than vesicles, these observations prompting the formulation of a vesicle-network coincidence model of the presynaptic terminal. This model has been tested by tracing the profiles of vesicles within the PTA network and comparing their size and shape frequency distributions with those of osmicated synaptic vesicles. The distributions have been found to be essentially similar, suggesting that vesicles can be located within the network, and that the hexagonal network units are formed only in the presence of an underlying vesicular matrix.Additionally, the following points have emerged: 1) the dense projections in the two types of material appear to be equivalent; 2) a loose correlation exists between dense projections and vesicles in osmicated terminals, increase in the area of the dense projections being associated with a decrease in the area of the vesicles; 3) network and dense projection units are similar. In view of the similarity between network and dense projection units, the demonstrated vesicular basis of the network raises the question of whether dense projections are entirely independent structures, or whether they depend in part for their existence on the nearby presence of synaptic vesicles.This work was supported by the Arnold Yeldham and Mary Raine Research Foundation of the University of Western Australia and by the Australian Research Grants Committee and the Nuffield Foundation     

The role of glucose in the lipid metabolism of the rat tapeworm Hymenolepis diminuta

The composition of the neutral lipids and the phospholipids, and the role of glucose in the lipid metabolism of prepatent (12-day-old) Hymenolepis diminuta has been studied in vitro. Triglyceride was the most abundant lipid present; substantial amounts of sterol and sterol ester, diglyceride, free fatty acids and monoglycerides were also present. The phospholipids, which were qualitatively and quantitatively similar to those of other invertebrates and vertebrates, were, in order of abundance, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphoinositide, lysophosphatidylcholine, cardiclipin, phosphatidic acid, lysophosphatidic acid and phosphatidylglycerol. Small amounts of glucose carbon were incorporated into the lipids, principally the water soluble (glycerol) moiety of the triglycerides; only traces were incorporated into the phospholipids. Small amounts of glucose were converted to inositol and galactose. The principal pathway of triglyceride synthesis is suggested to be via the α-glycerophosphate-phosphatidic acid-diglyceride pathway.     

Extensive size homoplasy at a microsatellite locus in the Japanese bumblebee, Bombus diversus

An extensive size homoplasy was found at microsatellite locus B11 of the bumblebee, Bombus diversus, in northern to central Honshu, Japan. A total of 16 alleles of different nucleotide sequences in five length morphs was obtained at B11 for this species. Of these alleles, five were 141 base pairs (bp) in length, five were 137 bp and four were 133 bp. Allele diversity in each length morph was high compared with previous studies. It is noteworthy that this extensive size homoplasy was found in a relatively small geographic area, in contrast to results from previous studies. Reconstruction of a median‐joining network revealed the complicated evolutionary process of the locus, involving insertion/deletion and point mutations. Preliminary estimation of the mutation rate of the B11 locus in B. diversus gives a value comparable to those estimated from experimental Drosophila populations. Effects of the extensive size homoplasy in population genetic studies is discussed.     

An ostracod-based calibration function for electrical conductivity reconstruction in lacustrine environments in Patagonia,Southern South America

In the Patagonian region (∼37–56°S) E of the Andes, the salinity and solute composition of lakes is strongly related to their location along the marked W-E decreasing precipitation gradient that is one of the main climatic features of the area. A calibration function (n = 34) based on 12 ostracod species (Ostracoda, Crustacea) was developed by WA-PLS to quantitatively reconstruct electrical conductivity (EC) values as a salinity proxy. The selected one component model had a r² = 0.74 and RMSEP and maximum bias equal to 16% and 31% of the sampled range, respectively, comparable to other published ostracod-based calibration functions. This model was applied to the ostracod record of the closed lake Laguna Cháltel (49°58′S, 71°07′W), comprising seven species and dominated by two species of the genus Limnocythere. In order to evaluate the calibration function’s robustness, the obtained EC values were compared with qualitative lake level and salinity variations inferred through a multiproxy hydrological reconstruction of the lake. Both reconstructions show good overall agreement, with reconstructed EC values in the oligo-mesohaline range (average: 11 060 ± 680 μS/cm) between 4570 and 3190 cal BP, corresponding to the ephemeral and shallow lake phases, and a marked decrease in EC concurrent with a lake level rise, reaching an average EC of 1140 ± 90 μS/cm during the deep lake phase (1720 cal BP to present). The variability in the reconstructed EC values for the ephemeral lake phase showed some inconsistency with the expected trend, which was attributed to time-averaging effects; for its part, the pace of the decrease in EC during the medium-depth phase (3190–1720 cal BP) differed from the expected, which could be due to autigenic effects (redissolution of salts) at the onset of this phase. This comparison not only lends support to the adequacy of the calibration function, but also suggests that its application in the context of a multiproxy study can greatly contribute to distinguish between autigenic and climatic-related controls of paleosalinity in closed lakes, allowing performing more accurate paleoenvironmental inferences on the basis of paleohydrological reconstructions.     

Functional morphology of the caudal skeleton in teleostean fishes

The basic function of the caudal skeleton in teleostean fishes is to support the caudal fin, but its parts contribute to this function in somewhat different ways. The main axis for this support is the upturned terminal end of the vertebral column, which ends at the base of the uppermost principal rays. The uroneural struts just ahead of this axis provide support for it. The parts of the caudal skeleton behind and below this upturned axis, the hypurals and parhypural, not only support the caudal rays but also provide a means for differential movements between the upper and lower parts of the fin base. This basic caudal skeleton varies with the position of the fish in the sequence of teleosten evolution, the way in which the fish uses its caudal fin, and to some extent with the shape of the fin.