Browsing by Author "Larsen, Peter A. (TTU)"
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Item Genetic Diversity of Neotropical Myotis (Chiroptera: Vespertilionidae) with an Emphasis on South American Species(2012) Larsen, Roxanne J. (TTU); Knapp, Michelle C. (TTU); Genoways, Hugh H.; Khan, Faisal Ali Anwarali (TTU); Larsen, Peter A. (TTU); Wilson, Don E.; Baker, Robert J. (TTU)Background: Cryptic morphological variation in the Chiropteran genus Myotis limits the understanding of species boundaries and species richness within the genus. Several authors have suggested that it is likely there are unrecognized species-level lineages of Myotis in the Neotropics. This study provides an assessment of the diversity in New World Myotis by analyzing cytochrome-b gene variation from an expansive sample ranging throughout North, Central, and South America. We provide baseline genetic data for researchers investigating phylogeographic and phylogenetic patterns of Myotis in these regions, with an emphasis on South America. Methodology and Principal Findings: Cytochrome-b sequences were generated and phylogenetically analyzed from 215 specimens, providing DNA sequence data for the most species of New World Myotis to date. Based on genetic data in our sample, and on comparisons with available DNA sequence data from GenBank, we estimate the number of species-level genetic lineages in South America alone to be at least 18, rather than the 15 species currently recognized. Conclusions: Our findings provide evidence that the perception of lower species richness in South American Myotis is largely due to a combination of cryptic morphological variation and insufficient sampling coverage in genetic-based systematic studies. A more accurate assessment of the level of diversity and species richness in New World Myotis is not only helpful for delimiting species boundaries, but also for understanding evolutionary processes within this globally distributed bat genus. © 2012 Larsen et al.Item Natural hybridization generates mammalian lineage with species characteristics(2010) Larsen, Peter A. (TTU); Marchán-Rivadeneira, María R. (TTU); Baker, Robert J. (TTU)Most diploid species arise from single-species ancestors. Hybrid origins of new species are uncommon (except among polyploids) and are documented infrequently in animals. Examples of natural hybridization leading to speciation in mammals are exceedingly rare. Here, we show a Caribbean species of bat (Artibeus schwartzi) has a nuclear genome derived from two nonsister but congeneric species (A. jamaicensis and A. planirostris) and a mitochondrial genome that is from a third extinct or uncharacterized congener. Artibeus schwartzi is self-sustaining, morphologically distinct, and exists in near geographic isolation of its known parent species. Island effects (i.e., area, reduced habitat variability, and geographic isolation) likely have restricted gene flowfrom parental species into the Caribbean populations of this hybrid lineage, thus contributing to local adaptation and isolation of this newly produced taxon. We hypothesize differential rates of the development of reproductive isolation within the genus and estimate that 2.5 million years was an insufficient amount of time for the development of postzygotic isolation among the three species that hybridized to produce A. schwartzi. Reticulated evolution thus has resulted in a genomiccombination from three evolutionary lineages and a transgressive phenotype that is distinct from all other known species of Artibeus. The data herein further demonstrate the phenomenon of speciation by hybridization in mammals is possible in nature.