2,375 research outputs found
Dietary Comparison of Eurycea cirrigera (Southern Two-lined Salamander) Larvae from Pond and Stream Habitats in Southern West Virginia
We give the first dietary report for a lentic population of two-lined salamander larvae (Eurycea bislineata complex) and the first dietary comparison of lentic and lotic populations simultaneously. Diets of Eurycea cirrigera (Southern Two-lined salamander) larvae were investigated from pond and stream habitats in southern West Virginia during 1994 and 1995. Pond larvae consumed nine prey taxa dominated by chironomid larvae and ostracods, with copepods contributing significantly on most sampling dates. Stream larvae consumed 15 prey taxa dominated by copepods, isopods, and chironomid larvae. Seasonal shifts in diet were apparent at both sites. Comparisons between sites (D = % dietary overlap and rs = Spearman rank correlation coefficient) indicate that larval diets are different at each site (D = 8.1-41.8; rs =-0.4091 to 0.5606, p = 0.l0-0.96). This is most likely due to differences in prey availability at each site. These results emphasize the generalist nature of Two-lined salamander larvae
Reproduction in West Virginia Populations of the Southern Two-lined Salamander (Eurycea cirrigera)
We describe reproduction in West Virginia populations of the southern two-lined salamander (Eurycea cirrigera) and provide insights into the behavioral ecology of this wide-ranging urodele. The first signs of reproduction are evident well before the arrival of Spring. Sexually mature adults inhabit the cold, rocky streams of southwestern West Virginia in early February. Females arc known by the presence of large oocytes visible through the body wall and males by their extremely swollen heads. Breeding occurs in the stream during late March and is marked by the presence of gravid females with sperm caps in their posterior cloacae. Eggs are deposited from mid-March through early April on the underside of flat rocks in cool, shallow, and swiftly flowing streams. Females guard their nests against potential predators, including other two-lined salamanders. Hatchlings emerge as miniature adults with gills after several months of development
Reference database of teeth images from the Family Bovidae
Researchers typically rely on fossils from the Family Bovidae to generate African paleoenvironmental reconstructions due to their strict ecological tendencies. Bovids have dominated the southern African fauna for the past four million years and, therefore, dominate the fossil faunal assemblages, especially isolated teeth. Traditionally, researchers reference modern and fossil comparative collections to identify teeth. However, researchers are limited by the specific type and number of bovids at each institution. B.O.V.I.D. (Bovidae Occlusal Visual IDentification) is a repository of images of the occlusal surface of bovid teeth. The dataset currently includes extant bovids from 7 tribes and 20 species (~3900). B.O.V.I.D. contains two scaled images per specimen: a color and a black and white (binarized) image. The database is a useful reference for identifying bovid teeth. The large sample size also allows one to observe the natural variation that exists in each taxa. The binarized images can be used in statistical shape analyses, such as taxonomic classification. B.O.V.I.D. is a valuable supplement to other methods for taxonomically identifying bovid teeth
Notes on the life history of the southern two-lined salamander, Eurycea cirrigera, in West Virginia
Abstract published in the proceedings of the 1997 Annual Meeting of the West Virginia Academy of Science
Elliptical Fourier Analysis of Crown Shape in Permanent Mandibular Molars From The Late Neolithic Cave Burials of Belgium
Prehistoric remains from caves and rockshelters are known from more than 250 sites situated along the Meuse River Basin of Belgium. Most of these osteological remnants date to the Late Neolithic period beginning after 4,500 years before present (BP), and five of these cave burials have been subject to intensive study, including Hastière Caverne M and Hastière Trou Garçon C from an earlier period of the Late Neolithic (4,345 ± 60 to 4,220 ± 45 years BP), Sclaigneaux and Bois Madame from the final/late Neolithic (4,155 ± 35 to 3,910 ± 40 years BP) and Maurenne Caverne de la Cave which dates to the final/late Neolithic period, 4,160 ± 45 to 3,830 ± 90 years BP and Middle Neolithic, 4,635 ± 45 years BP. Since the majority of the remains comprise gnathic fragments with in situ dental elements, comparisons between the caves are largely restricted to the teeth. Elliptical Fourier analysis of 40 permanent mandibular molar crown outlines from 27 individuals is utilized to address the degree to which chronology and ecogeography can explain the variation in crown shape across the caves. Although the sample sizes are limited, the cave burial of Hastière Caverne M appears to be distinctive. The variation within the cave burials of Sclaigneaux and Maurenne Caverne de la Cave is extensive, and a pronounced overlapping characterizes some of the sites. The results may provide evidence for increasingly broader contact between Late Neolithic farming communities of the Belgian Meuse basin prior to the Bronze Age
Analytical studies of particle dynamics in bending waves in planetary rings
Particles inside a planetary ring are subject to forcing due to the central
planet, moons in inclined orbits, self-gravity of the ring and other forces due
to radiation drag, collisional effects and Lorentz force due to magnetic field
of the planet. We write down the equations of motion of a single particle
inside the ring and solve them analytically. We find that the importance of the
shear caused by variation of the radial velocity component with local vertical
direction cannot be ignored and it may be responsible for damping of the
bending waves in planetary rings as observed by the Voyager data. We present
the wave profile resulting from the dissipation. We estimate that the surface
mass density of the C ring to be of the order of gm
cm, and the height m. These theoretical results are in
agreement with observations.Comment: 17 pages 3 figures MNRAS (In press
A New Snail-Eating Turtle of the Genus Malayemys Lindholm, 1931 (Geoemydidae) from Thailand and Laos
We describe a snail-eating turtle, Malayemys isan sp. nov., from the Mekong River Basin in northeastern Thailand (Nong Bua Lamphu, Nong Khai and Udon Thani provinces) and the adjacent Vientiane area in Laos. The new species is readily distinguishable from M. subtrijuga by its two (vs. six to nine) nasal stripes, and from both M. subtrijuga and M. macrocephala by its thin, often discontinuous, infraorbital stripe that never reaches the loreal seam. This geographically-restricted new species is sold in several food markets throughout the species‟ distribution and is in urgent need of conservation measures
Restoration of SMN in Schwann cells reverses myelination defects and improves neuromuscular function in spinal muscular atrophy
Spinal muscular atrophy (SMA) is a neuromuscular disease caused by low levels of SMN protein, primarily affecting lower motor neurons. Recent evidence from SMA and related conditions suggests that glial cells can influence disease severity. Here, we investigated the role of glial cells in the peripheral nervous system by creating SMA mice selectively overexpressing SMN in myelinating Schwann cells (Smn(−/−);SMN2(tg/0);SMN1(SC)). Restoration of SMN protein levels restricted solely to Schwann cells reversed myelination defects, significantly improved neuromuscular function and ameliorated neuromuscular junction pathology in SMA mice. However, restoration of SMN in Schwann cells had no impact on motor neuron soma loss from the spinal cord or ongoing systemic and peripheral pathology. This study provides evidence for a defined, intrinsic contribution of glial cells to SMA disease pathogenesis and suggests that therapies designed to include Schwann cells in their target tissues are likely to be required in order to rescue myelination defects and associated disease symptoms
- …