Pseudacris regilla

Recuero et al. (2006a) examined patterns of mtDNA variation (including new samples and additional samples presented by Ripplinger and Wagner (2004) and reviewed available allozyme data for Pseudacris regilla (sensu lato). They concluded that P. regilla should be partitioned into three species, P. regilla, P. sierra, and P. hypochondriaca (the original proposal included different names based on taxonomic errors that were subsequently corrected). The authors did not provide detailed maps or descriptions of the ranges of the three proposed species and did not describe the contact zones between P. sierra and the other two species. Subsequent nuclear DNA data (Barrow et al. 2014) did not support the taxonomy proposed by Recuero et al. (2006). Jadin et al. (2021) provided a molecular analysis that supported the species distinction (as Hyliola) of Pseudacris regilla, P. sierra, and P. hypochondriaca. Holycross (2022), following arguments by Barrow et al. (2014), await a more thorough analysis based on nuclear markers and extensive sampling in contact zones before recognizing multiple species in this clade.

Duellman et al. (2016) moved this species from the genus Pseudacris to Hyliola, but Faivovich et al. (2018) subsequently argued against its recognition. Both the Society for the Study of Amphibians and Reptiles (SSAR) and Amphibian Species of the World (ASW) have not accepted this change (Crother 2017, Frost 2020).

The range of P. regilla (sensu lato) extends from southern British Columbia in Canada southward through the United States to southern Baja California, Mexico, and east to Montana, Idaho, and Nevada. The species also occurs on the Channel Islands off southern California (Stebbins 2003). Desert populations in southern California probably were introduced, as were some populations in Arizona. An introduced population occurs in the Queen Charlotte Islands, British Columbia (Reimchen 1990), Canada, and on Revillagigedo Island in Alexander Archipelago, Alaska, where it was introduced in 1960 and is breeding (Waters 1992, Hodge 2004). Overall elevational range extends from sea level to around 3,540 meters (Stebbins 2003).

Under the taxonomic arrangement proposed by Recuero et al. (2006), the distributions of the species in the P. regilla complex presumably would be approximately as follows (Recuero et al. did not provide distributional details):

P. regilla: extreme southern Alaska (introduced), British Columbia, Washington, western Oregon, and northern California.

P. sierra: central California, Nevada, eastern Oregon, Idaho, western Montana, and presumably extreme northwestern Utah (extirpated?).

P. hypochondriaca: southern California, southern Nevada, southwestern Utah (extirpated?), and western Arizona south to southern Baja California.

This frog is well distributed along 90 km of the lower Colorado River and its backwaters from Davis Camp, just below Davis Dam, to Castle Rock in upper Lake Havasu, but the native versus exotic status of these populations is unclear (Rorabaugh et al. 2004). In Arizona, this species has been recorded as an apparent introduction at Middle Spring and a nearby stock tank in the Virgin Mountains, Mohave County, and at two central Arizona plant nurseries (Rorabaugh et al. 2004). It persisted for at least 19 years and successfully bred at one nursery, where it was reportedly introduced on ornamental plants imported from San Diego (Rorabaugh et al. 2004).

Represented by many and/or large occurrences throughout most of the range.

In most areas this species faces no major threats. It lives and breeds in a large number of natural and highly altered habitats. Introduced mosquitofish (Gambusia) prey heavily on larvae and may negatively affect local populations (Goodsell and Kats 1999). However, this is not a pervasive threat. In lakes in the Sierra Nevada, distribution and abundance were negatively related to non-native trout presence (Matthews et al. 2001).