Brownsville narrow-mouthed toad. Taxonomy Hypopachus variolosus is a variable species with a long list of synonyms. Sheep frogs occur in a wide range of color and pattern variations, calls, and toe structure, suggesting that the species as currently understood (2021) might represent a species complex. Description The sheep frog is a relatively small frog, 2.5-3.8 cm, with rare individuals exceeding 4 cm. Males average 3.3 mm and females average 3.8 mm. Distribution The sheep frog ranges through parts of Central America and Mexico, generally in lower elevation coastal areas below 1600 m, reaching its northernmost limit in far south Texas, US. On the Pacific coast it occurs from northwest Costa Rica, into western Nicaragua, north through western Mexico including the Balsas basin, into Sinaloa, and adjacent areas of extreme southern Sonora and Chihuahua. In Honduras and Guatemala it ranges across continent to the Atlantic (Caribbean Sea) coast, north into Belize and throughout the Yucatán Peninsula, up the coast to Nuevo León and Tamaulipas, Mexico, and adjacent areas of south Texas, US. Several areas within the range, such as southern Belize and northern Sinaloa lack records, suggesting possible gaps in the distribution. Conversely, relatively informal records available on internet web sites suggest the range extents significantly further into interior regions of southern Mexico than previously known. In the US, it occurs on the southern coast of Texas in at least 16 counties, from the lower Rio Grande Valley northward as far as Goliad County north of Corpus Christi. Some older maps indicate a distributional gap in northern Tamaulipas, Mexico, suggesting the Texas population is isolated from populations in southern Tamaulipas and Nuevo León. However, a few sparse records have appeared in recent years filling portions of that gap. Ecology and natural history Diet: Sheep frogs are diet specialist, feeding largely on termites and ants (Hymenoptera), although some minute flies (Diptera) and other insects are occasionally consumed as well. Habitat: Hypopachus variolosus is known to occur in a variety habitats, most frequently reported from semiarid thornscrub and savanna environments. It also occurs in drier open woodlands, as well as more humid canyons, basins, foothills and premontane forest up to 1000-1200 meters (ca. 1600 m. maximum). Disturbed areas such as pasturelands, irrigation ditches, and vacant lots are also occupied. One author wrote that it is absent from undisturbed moist lowland forest in southern Mexico and Central America. In Texas, it is restricted to