A Molecular Phylogeny for the Thermosphaeroma Species Complex


Meeting Abstract

P3.200  Tuesday, Jan. 6  A Molecular Phylogeny for the Thermosphaeroma Species Complex RODRIGUEZ, E.I*; SAUNDERS, K.; DAVIS, G.; SHUSTER, S.M.; AYERS, T. J; Northern Arizona University; Univ. of Florida; Univ. of Maryland, Baltimore Medical School; Northern Arizona University; Northern Arizona University eir4@nau.edu

The genus Thermosphaeroma (Crustacea:Isopoda:Sphaeromatidae) consists of 7 described freshwater species endemic to thermal springs in Texas and New Mexico in the United States, as well as in Chihuahua, Durango, Coahuila and Aguascalientes in the Republic of Mexico. The easternmost described species of the genus, T. subequalum, is found in at least 9 thermal springs located on both sides of the Rio Grande River over a 150 km distance. We used an approximately 470 base pair sequence from the mitochondrial 16S ribosomal RNA gene to investigate evolutionary relationships among these populations. Our analysis included sequences from mulitiple individuals from all known Thermosphaeroma species and populations, as well as from 4 other species belonging to 2 currently recognized Sphaeromatid subfamilies, the Dynameninae and the Sphaeromatinae. Our results provide (1) a molecular phylogeny for the genus Thermosphaeroma, (2) biogeographic data useful for studies of North American post-Cretaceous organisms, (3) support for the hypothesis that the Sphaeromatinae and the Dynameninae represent distinct Sphaeromatid lineages, and (4) evidence that Thermosphaeroma belongs within the latter subfamily.

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