DNA barcoding of springsnails (Mollusca, Gastropoda, Caenogastropoda) endemic to the Trans-Pecos region of Texas (USA)

In desert environments, unique communities depend on groundwater from springs, including a diverse radiation of small (<5 mm) snails found in the desert across the southwestern United States. Nearly all springs-nail species are considered critically imperiled with their existence depending on maintenance of spring-flows in regions of declining water availability. Extant, endemic springsnails in the Trans-Pecos region of Texas include one species of Pseudotryonia Hershler, 2001, five nominal Tryonia W. Stimpson, 1865 (Cochliopidae) and seven Pyrgulopsis Call & Pilsbry, 1886 (Hydrobiidae). Four of these are classified as endangered under the US Endangered Species Act. Surveys for springsnails were conducted at 128 sites, including 13 sites that were previously reported localities, and 115 previously unsampled spring sites were also searched for new springsnail populations. Sequences of the DNA barcoding region were used to establish a database of known sequences from the named species and confirm identifications of new populations encountered. We report eight new springsnail populations, including new records for T. metcalfi Hershler, Liu & Landye, 2011, T. cheatumi (Pilsbry, 1935), P. ignota Hershler, Liu & Lang, 2010, P. metcalfi (D.W. Taylor, 1987), and P. texana (Pilsbry, 1935). We were not able to recollect Juturnia brunei (D.W. Taylor, 1987), T. oasiensis Hershler, Liu & Landye, 2011, or P. davisi (D.W. Taylor, 1987). The DNA barcoding gap for Tryonia ranged from 1.56- 4.47% and for Pyrgulopsis from 0.68-1.68%.