Reinstatement of Euarche rudipalpa (Polychaeta: Acoetidae), with remarks on morphology and body pigmentation

Abstract

Eupanthalis rudipalpa Amaral & Nonato, 1984 was described based on three incomplete, colorless specimens and has not been reported since its original description; the epithet rudipalpa means "hirsute palps", a characteristic that separates it from other congeneric species. Eupanthalis McIntosh, 1876 and Euarche Ehlers, 1887, and their respective type species, E. kinbergi McIntosh, 1876 and E. tubifex Ehlers, 1887, were considered synonyms (E. rudipalpa as a junior synonym of E. tubifex, a cosmopolitan species) by some authors, because both have sessile eyes and two or three antennae. Nonetheless, these two genera are, in fact, distinct. Their type species can clearly be separated using some prostomial features. We provide an emended diagnosis of Euarche, and reinstate E. rudipalpa, redescribing it based on a Brazilian specimen (original type specimens lost). Illustrations showing body pigmentation pattern and a key to all species of Eupanthalis are also provided.