The Phylum Echinodermata contains near 7000 living species divided into five Classes. Throughout the years, much has been discovered about them. Besides traditional studies on their ecology, morphology and taxonomy, recent studies are emphasizing new subjects such as medicinal uses, paleoenvironmental indicators and even craftwork. In this study it is presented the occurrence of the Echinodermata species from the Bahia State (Brazil), which are represented by a total of seventy one living species and six fossils. Among the living species, eight belong to the Asteroidea Class, forty to the Ophiuroidea, thirteen to the Echinoidea, seven to the Holoturoidea and three to the Crinoidea. Even though the Bahia State has the longest coastal line, in the whole country, its diversity represent only 21 % of the currently registered Echinodermal fauna of Brazil.

Ophiotrichidae Ljungman, 1867 comprises brittle stars diagnosed by the absence of oral papillae and presence of a cluster of dental papillae covering at least half the height of the dental plate. Ophiothrix Müller & Troschel, 1840 is the largest genus in the family and is composed of many species with a highly variable morphology. Ophiothrix angulata is one species with descriptions showing morphological variation in many of the diagnostic characters stated by Say (1825) in the original description. Say's (1825) type material and specimens studied by him could be located. Thus, in order to elucidate the taxonomic identity of O. angulata and following Article 75 of the International Code for Zoological Nomenclature, here we propose the neotype designation of O. angulata based on topotype specimens from South Carolina, United States. A discussion of the records of O. angulata from the Atlantic Ocean is included. Taxonomic comments on the genus Ophiothrix are also provided.

A checklist of Gymnolaemata bryozoans from Bahia State, north-east Brazil, is presented. Specimens are lodged in the Bryozoa collection of the Museu de Zoologia at the Universidade Federal da Bahia (UFBA). The checklist comprises 135 species in 54 families, the majority belonging to the order Cheilostomata.

Brittle stars are considered one of the main benthic groups at the Brazilian coast, where they occur in high abundance and diversity. Ophiothrix Müller & Troschel, 1840 is among the most common genera of ophiuroids, with hundreds of specimens deposited in Brazilian Zoological Collections. Here we reviewed the species of Ophiothrix of Brazil and elucidated the taxonomic status of the six species previously reported in Brazilian waters—Ophiothrix ailsae Tommasi, 1970, Ophiothrix angulata (Say, 1825), Ophiothrix brachyactis H. L. Clark, 1915, Ophiothrix rathbuni Ludwig, 1882, Ophiothrix suensoni Lütken, 1856 and Ophiothrix trindadensis Tommasi, 1970. Three of these were not found among the 1.134 specimens analyzed in this study—O. ailsae, O. angulata and O. brachyactis. Most specimens previously attributed to these three taxa are here assigned to Ophiothrix brasiliensis n. sp. due having disc covered by short spines with 2–6 thorns at the apex and triangular radial shields covered only by short bifid and trifid spines. Three other new species are also described. Ophiothrix spiniformis n. sp. has a disc covered by long spines with denticules along their complete length and an apex with spinelets and radial shields covered by short bifid and trifid spines. Ophiothrix tommasii n. sp. is characterized by the interradial regions of the disc and radial shields being covered by spines with 2–7 thorns at the tip, and by the presence of small spines on the first dorsal arm plate. Ophiothrix troscheli n. sp. has a disc covered by long conical spines and naked, triangular radial shields. An identification key for the Ophiothrix species of Brazil is provided.