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Kulkoyluoglu O.,University of Science and Arts of Iran | Gibson R.,San Marcos National Fish Hatchery and Technology Center | Diaz P.H.,Texas Fish and Wildlife Conservation Office USFWS | Colin J.-P.,University of Lisbon

A new freshwater ostracod genus, Bicornucandona gen. nov. and its type species (Bicornucandona fineganensis sp. nov.) are described from Finegan Springs, Texas, U.S.A. The new genus differs from the related genera in the presence of two horn-like structures on the dorsal margin of the left valve in both sexes. This is also the diagnostic character of the type species. Differences in the structure of the hemipenes and prehensile palps of the male, and the shapes of some other soft body parts also separate this genus from the related species. Taxonomic status of the new genus and species are compared and discussed with both living and fossil relatives. © 2011 · Magnolia Press. Source

Xu X.,Wuhan University | Walters C.,U.S. Department of Agriculture | Antolin M.F.,Colorado State University | Alexander M.L.,San Marcos National Fish Hatchery and Technology Center | And 4 more authors.
Molecular Phylogenetics and Evolution

The wild-rice genus Zizania includes four species disjunctly distributed in eastern Asia and North America, with three species (Z. aquatica, Z. palustris, and Z. texana) in North America and one (Z. latifolia) in eastern Asia. The phylogeny of Zizania was constructed using sequences of seven DNA fragments (atpB-rbcL, matK, rps16, trnL-F, trnH-psbA, nad1, and Adh1a) from chloroplast, mitochondrial, and nuclear genomes. Zizania is shown to be monophyletic with the North American species forming a clade and the eastern Asian Z. latifolia sister to the North American clade. The divergence between the eastern Asian Z. latifolia and the North American clade was dated to be 3.74 (95% HPD: 1.04-7.23) million years ago (mya) using the Bayesian dating method with the combined atpB-rbcL, matK, rps16, trnL-F, and nad1 data. Biogeographic analyses using a likelihood method suggest the North American origin of Zizania and its migration into eastern Asia via the Bering land bridge. Among the three North American species, the organellar data and the haplotype network of the nuclear Adh1a gene show a close relationship between Z. palustris and the narrowly distributed endangered species Z. texana. Bayesian dating estimated the divergence of North American Zizania to be 0.71 (95% HPD: 0.12-1.54) mya in the Pleistocene. The non-monophyly of Z. palustris and Z. aquatica in the organellar and nuclear data is most likely caused by incomplete lineage sorting, yet low-frequency unidirectional introgression of Z. palustris into Z. aquatica is present in the nuclear data as well. Source

Fries J.N.,San Marcos National Fish Hatchery and Technology Center | Gibson J.R.,San Marcos National Fish Hatchery and Technology Center
Southwestern Naturalist

For captive-bred Devils River minnows (Dionda diaboli), which are federally listed as threatened, we measured critical thermal maxima when they were acclimated at 18, 22, 24, and 27°C. Critical thermal maxima were 32.6, 34.3, 35.3, and 37.8°C and were positively correlated with temperatures of acclimation, but not with either gender or size. There was high pre-test mortality (39) for fish held at 28°C for 72 days. Source

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