Systematics of Guyana and Brazilian Shield Endemic Loricariid Catfishes of the Tribe Ancistrini and Biogeography of the Shield Regions

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With 646 species, the Loricariidae (suckermouth armored catfishes) is one of the largest families of fishes in the world. Loricariids are distributed throughout much of South America and part of Central America where they fill significant ecological roles as algivores, detritivores, and lignivores (wood-eaters). Particularly speciose among the Loricariidae is the tribe Ancistrini of the subfamily Hypostominae. Amongst the Ancistrini, the major taxonomic and systematic problems revolve around a group of genera with ranges centered upon the Brazilian and Guyana Shields, two areas of ancient mountain ranges. In this study, the shield endemic groups of the Ancistrini will be examined to determine what species exist in the shield region and numerous undescribed taxa will be described. Once this is completed, the relationships of the species will be determined by various aspects of their morphology (such as bones) in order to reconstruct the biogeographical history of the shield region. By analyzing several groups with similar life histories, the way in which the shield regions have been invaded by fishes can be explored in detail. Particular emphasis will be placed on the Guyana Shield.From a conservation standpoint, although much of the Guyana Shield remains sparsely populated, some rivers have been incredibly impacted by gold and diamond mining. By studying the Guyana Shield Ancistrini now, we will have a better understanding of the diversity of fishes in the area before the area becomes irreversibly impacted. On a recent trip I took to the Potaro River in Guyana, several loricariids that should have been present were not captured suggesting that the extensive mining in the area has had a detrimental effect on them. Mining practices may have a particularly detrimental effect on loricariid catfishes because loricariids feed on biofilm that may become laced with pollutants from the mining industry and which may be harmed by the increased turbidity caused by dredging. It is imperative that studies into the shield fauna be accomplished soon so that we can have a better understanding of what we need to conserve and how it needs to be conserved before it is lost. This study will also provide the means to collect in poorly studied areas of South America. Many undescribed species of fishes will likely be collected in this study. In addition, tissues of all species collected will be taken for future genetic analyses and would allow for future toxicological analyses.