Dawkinsia
Dawkinsia is a genus of cyprinid fishes from freshwater in South India and Sri Lanka. It was split off from genus Puntius in 2012. The genus is endemic to South Asia; most species are found in the Western Ghats, with one inhabiting the Knuckles Hills of Sri Lanka. The Sri Lankan species colonized the island by crossing the Palk Isthmus during the Pliocene-Late Pleistocene.
Etymology
Dawkinsia is named after the evolutionary biologist Richard Dawkins in recognition of his "contribution to the public understanding of science, particularly, of evolutionary science". Dawkins describes this as "a great honour".The synonym Sahyadria alludes to the local name of the Western Ghats, Sahayadri, where the two species of that group are found.
Description
Adults typically measure SL. They do not have rostral barbels but may have maxillary barbels. Juveniles have a colour pattern consisting of three black bars on body; this persists in the adults of some species. Adults have a black, horizontally elongate blotch on the caudal peduncle. The last unbranched fin-ray of the dorsal fin is smooth and the lateral line is complete, with 18 to 22 scales.Three species groups can be distinguished: Filamentosa, Sahyadria, and Assimilis, though this is mostly based on molecular analyses; the Filamentosa and Assimilis group have plesiomorphies, shared features that the Sahyadria group do not possess, such as the extensions of the dorsal fin rays past the membrane. All three groups do, however, share the juvenile barred patterning.
Species
These are the currently recognized species in this genus:Dawkinsia apsara Dawkinsia arulius Dawkinsia assimilis Dawkinsia austellus Katwate, Marcus Knight, Anoop, Raghavan & Dahanukar, 2020Dawkinsia chalakkudiensis Dawkinsia crassa Katwate, Marcus Knight, Anoop, Raghavan & Dahanukar, 2020 Dawkinsia denisonii Dawkinsia exclamatio Dawkinsia filamentosa Dawkinsia lepida Dawkinsia rohani Dawkinsia rubrotincta Dawkinsia singhala Dawkinsia srilankensis Dawkinsia tambraparniei Dawkinsia uttara Katwate, Apte & Raghavan, 2020Phylogenetic analyses continually suggested that Dawkinsia was paraphyletic if Sahyadria were considered a distinct genus, so the two species of Sahyadria, Sahyadria denisonii and S. chalakkudiensis, were lumped into Dawkinsia. The following cladogram is based on a Bayesian inference of the concatenated mitochondrial dataset of the cyt b + cox1 gene:
Mitogenome analysis confirms that D. denisonii and D. chalakkudiensis are sister species; they comprise the Sahyadria group.