Cryptic speciation inLecane bulla(Monogononta: Rotifera) in Chihuahuan Desert waters

Abstract

The Chihuahuan Desert is known for its high biodiversity in both terrestrial and aquatic systems (Dinerstein et al. 2000, Souza et al. 2006). Endemism is pronounced in fishes (Minckley 1978) and springsnails (Hershler 1985); however, little is known regarding the distribution of many invertebrate groups. Dinger et al. 2005 recently surveyed the aquatic invertebrates in the diverse habitats at Cuatro Cienegas, Coahuila, Mexico, and noted the lack of taxonomic information for many insect groups in the region. Even less is known regarding the zooplankton of this and many other regions in the Chihuahuan Desert. Cosmopolitanism is assumed for many rotifers, including the monogonont Lecane bulla (Gosse 1851) (Koste 1978, Segers 1995). This species is characterized as one of the most eurytopic members of the Genus Lecane (Segers 1996), exhibits morphological variation, and is found in a variety of water sources worldwide. In his revision of the genus, Segers (1995) listed 11 species as synonyms with L. bulla but retained 3 recognized forms. More recently L. bulla goniata has been fully synonymized with L. bulla (Segers 2007). Because cryptic speciation is being detected with increasing frequency in rotifers (Gomez et al. 2002, Gomez 2005, Derry et al. 2003, Ortells et al. 2003, Gilbert & Walsh 2005, Suatoni et al. 2006, Schroder & Walsh 2007), we sampled sites from Chihuahuan Desert waters (U.S. and Mexico) to assess potential ecological and genetic differentiation of L. bulla.