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Morphological Details (morphological + detail)
Selected AbstractsObservations of the morphology of some known and new fragilarioid diatoms (Bacillariophyceae) from rivers in the USAPHYCOLOGICAL RESEARCH, Issue 2 2005Eduardo A. MoralesArticle first published online: 22 FEB 200 SUMMARY Morphological studies at the light microscopy and scanning electron microscopy levels of selected fragilarioid diatoms occurring in North American streams and lakes are presented herein. The majority of the samples studied were collected by the US Geological Survey's National Water Quality Assessment Program, which concentrates on stream water quality monitoring throughout the continental USA and Hawaii. Two new species (Staurosirella confusa Morales and Punctastriata mimetica Morales) and a new forma (Pseudostaurosiropsis geocollegarum f. triradiatum Morales) are described and two new combinations (Pseudostaurosira subsalina (Hustedt) Morales and Staurosirella olden-burgiana (Hustedt) Morales) are provided. Morphological details of an additional taxon, Staurosira construens var. binodis (Ehrenberg) Hamilton in Hamilton et al. are also presented. The taxonomic affinities of all these taxa, as well as some evolutionary aspects and ecologic characteristics, are discussed in the light of published material. [source] Genetic, geographic, and environmental correlates of human temporal bone variationAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2007Heather F. Smith Abstract Temporal bone shape has been shown to reflect molecular phylogenetic relationships among hominoids and offers significant morphological detail for distinguishing taxa. Although it is generally accepted that temporal bone shape, like other aspects of morphology, has an underlying genetic component, the relative influence of genetic and environmental factors is unclear. To determine the impact of genetic differentiation and environmental variation on temporal bone morphology, we used three-dimensional geometric morphometric techniques to evaluate temporal bone variation in 11 modern human populations. Population differences were investigated by discriminant function analysis, and the strength of the relationships between morphology, neutral molecular distance, geographic distribution, and environmental variables were assessed by matrix correlation comparisons. Significant differences were found in temporal bone shape among all populations, and classification rates using cross-validation were relatively high. Comparisons of morphological distances to molecular distances based on short tandem repeats (STRs) revealed a significant correlation between temporal bone shape and neutral molecular distance among Old World populations, but not when Native Americans were included. Further analyses suggested a similar pattern for morphological variation and geographic distribution. No significant correlations were found between temporal bone shape and environmental variables: temperature, annual rainfall, latitude, or altitude. Significant correlations were found between temporal bone size and both temperature and latitude, presumably reflecting Bergmann's rule. Thus, temporal bone morphology appears to partially follow an isolation by distance model of evolution among human populations, although levels of correlation show that a substantial component of variation is unexplained by factors considered here. Am J Phys Anthropol 2007. © 2007 Wiley-Liss, Inc. [source] Bdelloid Rotifers from Lakes above 1700 m in Western Italian Alps, with Taxonomic Notes on Dissotrocha macrostylaINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 6 2003Diego Fontaneto Abstract Benthic and periphytic bdelloid communities from 16 alpine lakes from 1700 to 2850 m above sea level in Sesia Valley (Piedmont region, North-western Italy), sampled during summer 2001 and 2002, were analyzed. Seventeen species were identified from these species-poor communities, with 1 to 6 species each. Dissotrocha macrostyla and Philodina citrina were the most common species, present in 10 lakes while 9 species were collected from one lake only. New morphological details from S.E.M. pictures of Dissotrocha macrostyla revealed that Dissotrocha macrostyla tuberculata (Gosse, 1886) is only a seasonal morphotype. Its different appearance is due to the presence of locally distributed microscopic mucous bubbles (diameter 1.41 ± 0.18 ,m) on the trunk surface, produced by the rotifer itself under stressful conditions. [source] A trace fossil assemblage from fluvial Old Red deposits (Wood Bay Formation; Lower to Middle Devonian) of NW-Spitsbergen, SvalbardLETHAIA, Issue 2 2004MAX WISSHAK From the fluvial Old Red Sandstone (ORS) of the Lower to Middle Devonian Wood Bay Formation (NW-Spitsbergen), a diverse trace fossil assemblage, including two new ichnotaxa, is described: Svalbardichnus trilobus igen. n., isp. n. is interpreted as the three-lobed resting trace of an early phyllocarid crustacean (Rhinocarididae). Cruziana polaris isp. n. yields morphological details that point towards a trilobite origin. This occurence of presumably marine trace makers in a fluvial red bed sequence raises the question of whether we are dealing with marine ingressions that are not sedimentologically expressed, with homeomorphy, or with an adaptation of marine groups to non-marine environments. [source] Appearance of Crypt Neurons in the Olfactory Epithelium of the Skate Raja clavata During DevelopmentTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 10 2007Sara Ferrando Abstract Crypt neurons are olfactory receptor cells located in the olfactory epithelium of fishes. They exhibit a peculiar and well-recognizable morphology, although their odorant specificity is still unknown. Data on their appearance during development are few and far between. This study set out to identify the time at which crypt neurons appeared in the skate, Raja clavata, using histological and immunohistochemical methods. For this purpose, embryos and juveniles at different stages of development, from 13 weeks after laying (11 weeks before hatching) to 24 weeks after hatching, were examined. The crypt neurons were identified on a morphological basis. An anti,,-tubulin antibody and two lectins (wheat germ agglutinin and peanut agglutinin) were used to highlight morphological details. The olfactory marker protein was detected by immunohistochemistry, because this protein is a marker of neuronal maturity in vertebrates. The crypt neurons could be detected by their morphology at 15 weeks after laying and became strongly olfactory marker protein immunoreactive 22 weeks after laying. Although involvement of crypt neurons in reproductive behavior has been inferred in various studies on bony fishes, their early presence in skate embryos and juveniles may suggest that they are not exclusively involved in sexual behavior. Anat Rec, 290:1268-1272, 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||