Telmatobius dankoi, also known as the Loa water frog, is a species of critically endangered aquatic frog in the family Telmatobiidae. It is endemic to Chile and is only known from its type locality near Calama, in the El Loa province. Only 14 individuals are known from captivity following the destruction of its habitat prior to 2019, so it may already be extinct in the wild. However, it is doubtfully distinct from Telmatobius halli and thus may not be a distinct species. Taxonomy The specific name dankoi honors professor , a Chilean geneticist. Prior to its description in 1999, it was confused with Telmatobius halli. However, multiple studies indicate little divergence between this species and Telmatobius vilamensis, and T. vilmanensis itself is doubtfully distinct from T. halli, and thus all three species may be conspecific with one another. Description Adult males measure and females in snout–vent length. There are small thorns on the posterior third of the body, flanks, head, and extremities. Tympanum and tympanic ring are absent. The toes are webbed. Males have small nuptial spines. The tadpoles are large: the longest measured tadpole was . The body is ovoid and measures about among the largest tadpoles. Habitat and ecology The species has been collected in small streams along the Loa River at about above sea level. The streams are bordered by Baccharis glutinosa and Tessaria absinthioides and are located in a high desert environment. Stomach contents of two adult specimens revealed a diet consisting of odonate larvae, snails of genus Littoridina, and amphipods (Hyalella gracilicornis); the last were the dominant group. Beetles from families Dytiscidae and Elmidae were present in the habitat but not identified in the stomach contents. Tapeworm Ophiotaenia calamensis was described as a new species based on specimens from the small intestine of this frog. Three tapeworms, measuring in total length, were found in the eight adult male frogs examined. Conservation In 2015, the International Union for Conservation of Nature (IUCN) assessed Telmatobius dankoi as being critically endangered. Its range is very small, and the habitat is affected by water pollution from mining activities. Additional threats are abstraction of surface water for human consumption and agriculture, as well as recreational activities. In 2019, a team of conservationists and indigenous leaders visited the type locality of the species and found that it had been devastated by water extraction by mining, agriculture, and real estate development, with