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Despite some remarkable recent discoveries, the Mesozoic fossil record of salamanders remains limited, particularly for the Jurassic. Here we describe the first articulated salamander skeleton from the Jurassic of Euramerica, recovered from Upper Jurassic deposits of the Morrison Formation, Dinosaur National Monument, USA. The specimen was studied using both conventional methods and high-resolution computed tomography. It shows a combination of primitive and derived character states that distinguish it from all known Mesozoic salamanders and which permit the erection of a new genus and species, Iridotriton hechti. The derived states (including the presence of spinal nerve foramina in the tail) suggest a position...
We used a phylogenetically based comparative approach to evaluate the potential for physiological studies to reveal patterns of diversity in traits related to susceptibility to an environmental stressor, the trace metal cadmium (Cd). Physiological traits related to Cd bioaccumulation, compartmentalization, and ultimately susceptibility were measured in 21 aquatic insect species representing the orders Ephemeroptera, Plecoptera, and Trichoptera. We mapped these experimentally derived physiological traits onto a phylogeny and quantified the tendency for related species to be similar (phylogenetic signal). All traits related to Cd bioaccumulation and susceptibility exhibited statistically significant phylogenetic signal,...
The morphologies, halotolerances, temperature requirements, pigment compositions and 16S rRNA gene sequences of five culture collection strains and six novel isolates of cyanobacteria with helical, tightly coiled trichomes were investigated. All strains were very similar morphologically and could be assigned to the genus Spirulina (or section Euspirulina sensu Geitler), according to traditional classification. However, the isolates showed significantly different requirements for salinity and temperature, which were in accordance with their respective environmental origins. The genetic divergence among the strains investigated was large. The results indicate the drastic underestimation of the physiological and phylogenetic...
Zhou, H., Fend, S. V., Gustafson, D. L., De Wit, P. & Erséus, C. (2010). Molecular phylogeny of Nearctic species of Rhynchelmis (Annelida). — Zoologica Scripta, 39, 378–393. The Nearctic species of Rhynchelmis (Clitellata, Lumbriculidae) are known primarily from cool-water habitats in western North America. Their taxonomy has so far been based on limited collections from isolated localities, using intuitive assessment of morphological characters. This approach has proved unsatisfactory when additional populations of closely related species were sampled and scrutinized for incorporation in the present classification. Therefore, in this study, mitochondrial (cytochrome c oxidase subunit I and 16S rDNA) and nuclear...
Global conservation prioritization usually emphasizes areas with highest species richness or where many species are thought to be at imminent risk of extinction. However, these strategies may overlook areas where many species have biological traits that make them particularly sensitive to future human impact but are not yet threatened because such impact is currently low. In this article, we identify such areas for the world's mammals using latent extinction risk, the discrepancy between a species' current extinction risk and that predicted from models on the basis of biological traits. Species with positive latent risk are currently less threatened than their biology would suggest, usually because they inhabit...
We used variation in a portion of the mitochondrial DNA control region to examine phylogeography of Tamiasciurus hudsonicus, a boreal-adapted small mammal in the central Rocky Mountain region. AMOVA revealed that 65.66% of genetic diversity was attributable to variation within populations, 16.93% to variation among populations on different mountain ranges, and 17.41% to variation among populations within mountain ranges. Nested clade analysis revealed two major clades that likely diverged in allopatry during the Pleistocene: a southern clade from southern Colorado and a northern clade comprising northern Colorado, Wyoming, eastern Utah, and eastern Idaho. Historically restricted gene flow as a result of geographic...
Bats (Chiroptera) represent one of the largest and most diverse radiations of mammals, accounting for one-fifth of extant species. Although recent studies unambiguously support bat monophyly and consensus is rapidly emerging about evolutionary relationships among extant lineages, the fossil record of bats extends over 50 million years, and early evolution of the group remains poorly understood. Here we describe a new bat from the Early Eocene Green River Formation of Wyoming, USA, with features that are more primitive than seen in any previously known bat. The evolutionary pathways that led to flapping flight and echolocation in bats have been in dispute, and until now fossils have been of limited use in documenting...
Recent fieldwork in the Gardnerbuttean (earliest Bridgerian) sediments along the northeastern edge of the Green River Basin at South Pass, Wyoming, has yielded a large and diverse sample of omomyid (tarsiiform) primates. This assemblage includes two species each of Artimonius gen. nov., Washakius, and Omomys, one species ofAnaptomorphus , Trogolemur and Uintanius, and a new, primitive species of the rare omomyine genus,Utahia . Utahia is known elsewhere only from its type locality in the Uinta Basin and its phylogenetic position is poorly understood. Utahia carina sp. nov. allows for re-evaluation of the affinities of this genus relative to other omomyines. In most characters, such as a lesser degree of molar trigonid...
Phenotype and molecular approaches were applied to the study diversity of 14 original soil Nostoc strains. Obtained data were compared with other molecular and phenotypic data of soil and symbiotic strains. Morphology of cells, filaments, hormogonia and mucilaginous sheaths were observed. Special attention was paid to life cycles. Considerable variability was found by both (the molecular and the morphological) approaches. Nine clusters sharing similarity of 95% were obtained analysing 87 16S rDNA Nostoc sequences. In some of them a significant correlation between results of molecular and morphological approach was found. Published in Algological Studies, volume 117, issue 1, on pages 251 - 264, in 2005.
Freshwater mussels (unionids) are increasingly recognized as important providers of ecosystem services, yet are among the most endangered fauna in the world. Because unionids are generally sessile and require specific fish hosts for development and dispersal, they are particularly vulnerable to habitat degradation. Surprisingly, little is known about the distribution of genetic diversity in freshwater mussels and this gap has a negative impact on taxonomy, monitoring, conservation and ecological research in these species. Here, we focus on western North American Anodonta, one of only three genera known to exist in this broad landscape and which contains three highly divergent lineages. We describe phylogeographical...
    map background search result map search result map A Late Jurassic salamander (Amphibia: Caudata) from the Morrison Formation of North America A Late Jurassic salamander (Amphibia: Caudata) from the Morrison Formation of North America