161 research outputs found

    The Mexican Blindcat Project: new discoveries and future efforts

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    content from an oral presentation March, 2017 at the 5th Astyanax International Meeting (http://www.stowers.org/sites/all/themes/aimfc/aim2017_prog.pdf)The endangered Mexican blindcat (Prietella phreatophila, Carranza 1954) is one of only four stygobitic ictalurid catfish in North America. Members of two monotypic genera (Satan eurystomus and Trogloglanis pattersoni) are known from the Edwards Aquifer in Texas and, until recently, Prietella (represented by P. lundbergi and P. phreatophila) was only known to occur in Mexico (northern Coahuila to southern Tamaulipas). The recent discovery of P. phreatophila in a cave on the Amistad National Recreation Area in Val Verde County, Texas is the result of decades of sporadic effort on both sides of the US/Mexican border and has stimulated a renewed effort to investigate the distribution, ecology, evolutionary history, and conservation status of this species. Collaborative efforts among The San Antonio Zoo, The University of Texas at Austin, Zara Environmental and The National Park Service are currently focused on habitat surveys in Texas as well as captive husbandry and propagation. Future efforts will include collaborators from the Comisión Nacional de Áreas Naturales Protegidas, Área de Protección de Recursos Naturales Sabinas, and the Laboratorio de Genética para la Conservación, Centro de Investigaciones Biológicas del Noroeste, La Paz to conduct expanded fieldwork in Mexico, hydrogeologic studies, and surveys using environmental DNA.San Antonio Zoo; University of Texas at Austin, Biodiversity Center, College of Natural Sciences; U.S. National Park ServiceIntegrative Biolog

    Using the Fishes of Texas Project Databases and Recent Collections to Detect Range Expansions by Four Fish Species on the Lower Coastal Plain of Texas

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    The Fishes of Texas project online database is a large, freely available quality controlled fish occurrence database of museum vouchered specimens. We used data from it, the same project’s separate database of occurrences extracted from published literature and our own recent survey data to examine range stability for four fish species inhabiting the Texas Lower Coastal Plain: Fundulus chrysotus, Fundulus jenkinsi, Heterandria formosa and Poecilia formosa. A weakness of our data is that they consist of presences only and species absences can only rarely be inferred. To help adjust for this we used common widespread species as proxies for the four target species by using captures of these proxy species as indicators that the collecting methods used were appropriate to capture the target species, assuming then that large numbers of occurrences of the proxies with contemporaneous absence of the target species in the same samples supports inferences of probable absence of target species. We here report new and previously unpublished occurrences for these species and document westward range expansions for H. formosa and F. chrysotus, an eastward range expansion for P. formosa, and a pattern of possible range contraction and expansion for F. jenkinsi

    Trophic polymorphism and behavioral differences decrease intraspecific competition in a cichlid, Herichthys minckleyi

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    Resource polymorphisms, or morphological variations related to resource use, are common in fishes and are thought to be a possible step in speciation. This study experimentally tests the hypothesis that fitness (as estimated by growth rates) is increased by the presence of multiple trophic morphotypes (or morphs) within a population. Cage experiments were used to quantify the intraspecific competitive interactions between morphs of the polymorphic cichlid Herichthys minckleyi in Cuatro Cienegas, Mexico. Results suggest that competition is reduced between morphs in mixed-morph treatments relative to equal-density single-morph treatments. Field studies revealed that the morphs feed in different microhabitats and use different feeding behaviors within these microhabitats. These results suggest that the polymorphism is maintained in the population because it decreases competition between the morphs, and that differences in feeding behavior facilitate resource partitioning
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