Status of Freshwater Mussels in Texas

Authors: K. Winemiller, N. K. Lujan, R. N. Wilkins, R. T. Snelgrove, A. M. Dube, K. L. Skow, A. G. Snelgrove

We requested records of Texas freshwater mussels (Unionidae) from 15 institutional biodiversity collections in the United States and Canada, all but two of which were outside of Texas. Results of these queries were standardized and collated into a Texas Freshwater Mussel Database (TFMD) consisting of 7442 records, dating from 1829 to 2005. Staff of the Institute of Renewable Natural Resources georeferenced all records based on verbatim locality data attached to each record. Precision of locality data varied from exact coordinates to generalized locations such as county or river basin, and georeferenced records were categorized accordingly. Taxonomies under which many of these records are being curated did not reflect current usage as compiled by Howells et al. (1996); therefore, synonyms were assigned according to that reference and the MUSSEL Project Simpson-Haas Index available online. Based on this revised taxonomy, our database comprises records of 51 unionid species currently recognized from Texas, and includes 877 records for 10 of the 11 species currently petitioned for listing as federally endangered or threatened (there are no records for the Salina mucket)(Fig. 1). Every major river basin in Texas with the exception of the Canadian and Red river basins has at least one record of a currently state threatened, federally petitioned, or federal candidate species. (Table 1)(Fig. 2). This latter subset of records dates from 1889 to 2005. The most common species in the database is the Threeridge, with 668 records, followed by the Pondhorn (596 records) and Tampico Pearlymussel (543 records) (Fig. 1).