Swamp eel: Blood-red subterranean dweller is newest fish genus discovered

Together with a group of international colleagues, Senckenberg scientist Ralf Britz described a new fish genus. The blind fishes, which are members of the swamp eel family, live in subterranean waters in Southern India and show a red coloration. Moreover, the team assigned three additional species to the new genus. The study was recently published in the scientific journal Ichthyological Exploration of Freshwaters.

Swamp eels (Synbranchidae) have an elongated body that lacks pectoral, pelvic, dorsal, anal, and caudal fins. They can be found on all continents except for Antarctica. "A total of 26 species has been confirmed for this family of bony fishes. A 'hotspot' with six species can be found in the Western Ghats, a mountain range along the west coast of India," explains Dr. Ralf Britz of the Senckenberg Natural History Collections in Dresden, and he continues, "The specimen we examined was captured in 1998 near a small village in Kerala State and was described as Monopterus roseni by two American scientists. It belongs to the local subterranean fish fauna, which currently includes 10 species from five families."

Using computer tomography and genetic methods, the biologist from Dresden, along with researchers from India and the U.S., discovered that Monopterus roseni and three other red-colored, subterranean species differed significantly from all of the remaining swamp eel species. "These studies, which have only been possible now, ultimately led to the introduction of a new genus, Rakthamichthys, for these four species. The species previously described as Monopterus roseni now becomes the type species for this new genus, bearing the updated name Rakthamichthys roseni," explains Britz.

The type species is blind, with a length of approximately 17 centimeters, and lives in subterranean, aquiferous laterite layers. "These extremely slender animals show a bright red coloration, which is reflected in the new genus name: Raktham means 'blood-red' in the Malayalam language; the suffix ichthys is the Greek word for fish," adds Britz in conclusion.