Browsing by Subject "Vertebrates"
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Item Letter to Bill Berggren from H.B. Stenzel on 1958-06-04(1958-06-04) Stenzel, Henryk B.Item New Early Miocene Formation and Vertebrate Local Fauna, Big Bend National Park, Brewster County, Texas(Texas Memorial Museum, The University of Texas at Austin, 1968-08) Stevens, Margaret S.; Stevens, James B.; Dawson, Mary R.The early Miocene Delaho (new) Formation is a locally derived sequence of basin fill sediments now severely deformed by later Tertiary normal faulting. These sediments contain the Castolon local fauna comprising seventeen mammalian taxa. Three genera are new. Age of the Castolon local fauna is considered middle Arikareean, and differences between it and other Arikareean faunas are caused in part by ecological bias.Item Protein Family Expansions and Biological Complexity(Public Library of Science, 2006-05-26) Vogel, Christine; Chothia, CyrusDuring the course of evolution, new proteins are produced very largely as the result of gene duplication, divergence and, in many cases, combination. This means that proteins or protein domains belong to families or, in cases where their relationships can only be recognised on the basis of structure, superfamilies whose members descended from a common ancestor. The size of superfamilies can vary greatly. Also, during the course of evolution organisms of increasing complexity have arisen. In this paper we determine the identity of those superfamilies whose relative sizes in different organisms are highly correlated to the complexity of the organisms. As a measure of the complexity of 38 uni- and multicellular eukaryotes we took the number of different cell types of which they are composed. Of 1,219 superfamilies, there are 194 whose sizes in the 38 organisms are strongly correlated with the number of cell types in the organisms. We give outline descriptions of these superfamilies. Half are involved in extracellular processes or regulation and smaller proportions in other types of activity. Half of all superfamilies have no significant correlation with complexity. We also determined whether the expansions of large superfamilies correlate with each other. We found three large clusters of correlated expansions: one involves expansions in both vertebrates and plants, one just in vertebrates, and one just in plants. Our work identifies important protein families and provides one explanation of the discrepancy between the total number of genes and the apparent physiological complexity of eukaryotic organisms.Item The Vale Formation (Lower Permian) Its Vertebrates and Paleoecology(Texas Memorial Museum, The University of Texas at Austin, 1982-03) Olson, Everett C.; Mead, James G.The Vale Formation is a wedge of predominantly terrestrial sediments of Leonardian age (Permian), overlying the Clear Fork Group and underlying the Choza Formation. Studies of the terrestrial vertebrates and stratigraphy of the Vale Formation, carried on since the late 19305, provide the basis for an initial synthesis of the faunas, stratigraphic distribution, paleoecology, taphonomy, and evolution of the vertebrates. Attention is focused on four principal outcrop areas: the northern Vale outcrop, with a complete section, largely in Knox County, Texas; the Sid McAdams locality, in the lower part of the Vale in southern Taylor County, Texas; the Blackwood locality, middle part of the Vale in central Taylor County, Texas; and the Stamford locality, middle part of the Vale in southern Haskell County, Texas. In addition, numerous other small sites in Texas and localities of equivalent age in Oklahoma were used in the analyses. Except for the northern Vale outcrops, the fossil vertebrate localities have been treated only briefly or not at all in previous publications. A study of fossil occurrences over a north-south distance of about 190 km in Texas, and of sections ranging up to 150 m thick, has provided a basis for tentative conclusions. The primary differences between the Vale and Arroyo faunas are the result of loss of genera and species in the upper part of the Arroyo Formation. New species were introduced early in the north and they, or their derivatives, appeared later to the south. Conditions of deposition pass from paralic in the south to strictly terrestrial with stream action predominant in the central and northern parts of the area. During deposition of the Vale Formation, especially in the north, climates were marked by increasing dryness and seasonality of rainfall. Most vertebrate remains were transported into the areas where they have been found. Only in ephemeral lakes and ponds were the organisms preserved where they lived. There is little evidence of pronounced evolutionary change during deposition of the Vale. Some speciation seems to have taken place, but faunal differences between areas were primarily related to climatological and physiographic differences. The fauna of the Vale does not differ significantly from that of the overlying Choza Formation. The report brings together all available information on the Vale faunas. Firmer interpretations of the evolution of the faunas will become possible when wider chronological and spatial distribution of vertebrates is known and after additional stratigraphic and paleoecological field studies have been completed.Item Versatility and Stereotypy of Free-Tailed Bat Songs(Public Library of Science, 2009-08-25) Bohn, Kirsten M.; Schmidt-French, Barbara; Schwartz, Christine; Smotherman, Michael; Pollak, George D.In mammals, complex songs are uncommon and few studies have examined song composition or the order of elements in songs, particularly with respect to regional and individual variation. In this study we examine how syllables and phrases are ordered and combined, ie “syntax”, of the song of Tadarida brasiliensis, the Brazilian free-tailed bat. Specifically, we test whether phrase and song composition differ among individuals and between two regions, we determine variability across renditions within individuals, and test whether phrases are randomly ordered and combined. We report three major findings. First, song phrases were highly stereotyped across two regions, so much so that some songs from the two colonies were almost indistinguishable. All males produced songs with the same four types of syllables and the same three types of phrases. Second, we found that although song construction was similar across regions, the number of syllables within phrases, and the number and order of phrases in songs varied greatly within and among individuals. Last, we determined that phrase order, although diverse, deviated from random models. We found broad scale phrase-order rules and certain higher order combinations that were highly preferred. We conclude that free-tailed bat songs are composed of highly stereotyped phrases hierarchically organized by a common set of syntactical rules. However, within global species-specific patterns, songs male free-tailed bats dynamically vary syllable number, phrase order, and phrase repetitions across song renditions.