''Hamaticolax unisagittatus'' is a species of

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

belonging to the family

Bomolochidae Bomolochidae is a family (biology), family of copepods parasitic on marine fishes. Most species parasitize the gills of fish, but some species live in the nostrils or on the eyes of their hosts. The family contains just over 150 species from the ...

. It is a parasite on the

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s of the

common snook The common snook (''Centropomus undecimalis'') is a species of Seawater, marine fish in the family (biology), family Centropomidae of the order (biology), order Perciformes. The common snook is also known as the sergeant fish or robalo. It was o ...

and has only been recorded in coastal waters off

Rio de Janeiro State Rio de Janeiro () is one of the 27 federative units of Brazil. It has the second largest economy of Brazil, with the largest being that of the state of São Paulo. The state, which has 8.2% of the Brazilian population, is responsible for 9.2% of ...

. In one study over half of the host fish sampled in this area carried this parasite. The female is up to long; the male is as yet unknown. Originally described in the genus '' Acantholochus'', it was later transferred to the genus ''

Hamaticolax ''Hamaticolax'' is a genus of parasitic copepods belonging to the family Bomolochidae. Its members can only be distinguished from the closely related genus ''Acantholochus'' by the presence of an accessory process on the claw of the maxillipeds. ...

''.

References

Poecilostomatoida Crustaceans of the Atlantic Ocean Crustaceans described in 2003 {{copepod-stub