An inventory of springsnails (Pyrgulopsis spp.) in and adjacent to the Spring Mountains, Nevada

Authors

Kevin S. McKelvey, USDA Forest Service, National Genomics Center, Rocky Mountain Research Station, Missoula, MT 59801Follow
Corey Kallstrom, U.S. Fish and Wildlife Service, Southern Nevada Fish and Wildlife Office, Las Vegas, NV 89130Follow
Jeri Ledbetter, Spring Stewardship Institute, Flagstaff, AZ 86001Follow
Donald W. Sada, Desert Research Institute, Reno, NV 89512Follow
Kristine L. Pilgrim, USDA Forest Service, National Genomics Center, Rocky Mountain Research Station, Missoula, MT 59801Follow
Michael K. Schwartz, USDA Forest Service, National Genomics Center, Rocky Mountain Research Station, Missoula, MT 59801Follow

Abstract

Springsnails (genus Pyrgulopsis, hereafter pyrgs) are small freshwater aquatic gastropods that occur in isolated springs in western North America. Pyrgs are species of conservation concern, but patterns of occupancy and speciation are complex. We investigated patterns of occurrence for pyrgs in the Spring Mountains, Clark County, Nevada. We were primarily concerned with identifying springs containing the species P. deaconi, the Spring Mountains pyrg, and P. turbatrix, the southeast Nevada pyrg. We identified species through genetic analysis of the COI-1 mitochondrial region and examined patterns of genetic structure. We located aquatic gastropods in 26 springs and analyzed 420 aquatic gastropods, of which 392 were pyrgs, the remainder representing an unknown species of Physa. Of the 26 springs, 25 contained pyrgs and 5 contained Physa sp. For pyrgs, at COI-1 we identified a total of 29 haplotypes that formed 6 distinct monophyletic groups. Five of the 6 groups were consistent with pyrgs previously identified: P. bacchus, P. deaconi, P. fausta, P. turbatrix, and an unknown species which had been identified previously in the Grapevine Springs. The sixth group, found in 2 springs, does not match any reference specimen and is genetically divergent from the other 5 groups. It is most closely related to P. micrococcus. Prior to this study, P. bacchus had not been located in the Spring Mountains. Both P. deaconi and P. turbatrix were located in multiple springs on both the east and west sides of the Spring Mountains, even though the Las Vegas Valley (east) and Pahrump Valley (west) are hydrologically distinct. At the scale of the hydrologic basin, genetic structure was not discernable; haplotype divergence did not align with basin boundaries and the most common haplotype for P. turbatrix occurred on both the east and west sides of the Spring Mountains. While there was little evidence for genetic structuring at the hydrologic-basin level, there was good evidence for structuring at the level of the individual spring. All told, 79% (23/29) of pyrg haplotypes were unique to specific springs, suggesting that pyrg diversity primarily occurs at the level of the individual spring.


Los caracoles del género Pyrgulopsis (en adelante pyrg) son pequeños gasterópodos acuáticos de agua dulce que habitan en manantiales aislados del oeste de América del Norte. Las especies de esté género, se encuentran en peligro de extinción. Sin embargo, sus patrones de ocupación y especiación son complejos. En el presente trabajo investigamos los patrones de incidencia de los caracoles pyrgs en Spring Mountains, condado de Clark, Nevada. Nuestro objetivo principal fue identificar los manantiales que albergan las especies P. deaconi (el pyrg de Spring Mountains) y P. turbatrix, (el pyrg del sureste de Nevada). Identificamos las especies mediante un análisis genético de la región mitocondrial COI-1 y examinamos los patrones de estructura genética. Localizamos gasterópodos acuáticos en 26 manantiales y analizamos 420 gasterópodos acuáticos, de los cuales 392 fueron pyrgs y el resto perteneciente a una especie desconocida de Physa. En 25 de los 26 manantiales, hallamos pyrgs y en cinco hallamos Physa sp. En la región mitocondrial COI-1 de los caracoles del género pyrgs identificamos un total de 29 haplotipos, que formaron seis grupos monofiléticos distintos. Cinco de los seis grupos fueron consistentes con pyrgs previamente identificados: P. bacchus, P. deaconi, P. fausta, P. turbatrix y una especie desconocida, previamente identificada en Grapevine Springs. El sexto grupo (hallado en dos manantiales) no coincide con ningún espécimen de referencia, diverge genéticamente de los otros cinco grupos y está más estrechamente relacionado con P. micrococcus. Previo a este estudio, no había registros del P. bacchus en Spring Mountains. Tanto los P. deaconi como los P. turbatrix fueron hallados en múltiples manantiales en los lados este y oeste de Spring Mountains. A pesar de que, el valle de Las Vegas (este) y el Valle de Pahrump (oeste) son hidrológicamente distintos. En cuanto a la cuenca hidrológica, la estructura genética no fue discernible; la divergencia del haplotipo no se alineó con los límites de la cuenca y el haplotipo más común del P. turbatrix ocurrió a ambos lados este y oeste de Spring Mountains. Aunque, existe poca evidencia de estructuración genética en la cuenca hidrológica, hubo indicios de estructuración a nivel del manantial individual. En total, el 79% (23/29) de los haplotipos de los pyrg fueron exclusivos de manantiales específicos, indicando que la mayor diversidad de caracoles del género pyrgs se encuentra a nivel de manantiales individuales.

Recommended Citation

McKelvey, Kevin S.; Kallstrom, Corey; Ledbetter, Jeri; Sada, Donald W.; Pilgrim, Kristine L.; and Schwartz, Michael K. (2020) "An inventory of springsnails (Pyrgulopsis spp.) in and adjacent to the Spring Mountains, Nevada," Western North American Naturalist: Vol. 80: No. 2, Article 6.
Available at: https://scholarsarchive.byu.edu/wnan/vol80/iss2/6