IRFP: Upland Biogeography and Adaptive Radiation of the Neotropical Rubbernose Loricariids

Lujan Nathan K, Nashville TN

Investigators

Abstract

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award is co-funded with the Americas Program in the Office of International Science and Engineering. This project will generate a time-calibrated, multilocus molecular phylogeny for seven genera of South American montane suckermouth armored-catfishes (Loricariidae) endemic to upland rivers and streams of the Andes Mountains and the geologically ancient Guiana Shield. An existing morphology-based phylogeny for this Trans-Highland Clade (THC) supports its monophyly and its placement within the tribe Ancistrini (Siluriformes: Loricariidae), and indicates that Andean lineages are monophyletic and derived from Guiana Shield lineages. The new THC phylogeny generated by this project will 1) test previous morphology-based hypotheses and 2) will be used to study rates and timing of THC geographic dispersal and vicariance, as well as rates of jaw morphological and trophic ecological diversification -- addressing both intrinsic and extrinsic mechanisms of diversification within Loricariidae, the most species-rich family of catfishes and one of the most diverse and specialized groups of fishes. This study will be the first to use an explicitly phylogenetic context to investigate rates and timing of loricariid biogeographic dispersal and jaw morphological and associated trophic ecological diversification. By investigating both intrinsic and extrinsic evolutionary influences, it will have ramifications not only for the fields of Neotropical ichthyology and South American biogeography, but also for the understanding of fundamental processes driving organismal evolution. This project will train one full-time post-doctoral researcher and will train students in Canada and in each of the Andean countries across which Trans-Highland Clade (THC) Loricariidae species are distributed. The PI and hosts have a history of working with women and under-represented ethnic groups in Colombia, Peru, Venezuela, and Guyana. This proposal will strengthen these collaborations and expand educational opportunities to Ecuador. The PI is currently mentoring Peruvian and Venezuelan biologists on taxonomic revisions of the THC genus Chaetostoma in their respective countries. These student researchers have morphometric datasets already containing hundreds of specimens. As part of this proposal, mentoring will be broadened to students in Ecuador and Colombia - allowing for a comprehensive, collaborative, taxonomic revision of the long-problematic genus Chaetostoma. The PI and hosts will seek additional support for visits by each international student to Toronto for advanced training in taxonomic discrimination via morphometrics and the publication of taxonomic results. Major results of this proposal, including a Chaetostoma taxonomic revision, a species-level Trans-Highland Clade (THC) phylogeny, and a refined understanding of THC trophic ecological function, will also assist aquatic conservation efforts focused on the Andean and Guiana Shield highlands, where anthropogenic impacts are rapidly expanding.