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Deep-sea ophiuroids from western Mexico have been documented since 1899, but mostly by non-Mexican expeditions. TALUD is a Mexican project designed to study the deep-sea fauna from Mexico. As part of it, the present contribution provides for the first time detailed information about the taxonomy and distribution, as well as images, of deep-sea ophiuroids from western Mexico, representing a useful taxonomic identification tool for Ophiuroidea from the eastern Pacific. A total of 38 species of ophiuroid (35 identified at species level, one at genus level, and two as confer) were collected from 83 stations located at 123‒2,309 m depth. At a regional scale, several new species records are presented: six for western Baja California, five for western Baja California Sur, two for the Gulf of California, four for Jalisco, 14 for Colima, and five for Guerrero. Geographic (six) and bathymetric (seven) distribution ranges of species are extended. An updated list of deep-sea ophiuroids (61 species) from western Mexico is provided together with an identification key to species collected during this survey. In addition, nine records of deep-sea ophiuroids for the Mexican Pacific are unproven, doubtful or invalid. We corroborated the presence of Ophiacantha eurypoma and Ophiacantha pacifica in the study area and added Amphiura gymnogastra as the first record for Mexico. We propose to transfer Ophiacantha phragma to Ophiolimna on account of it having both granules and spines on the dorsal disc and striated arm plates. TALUD cruises collected 57 % of the total deep-sea species known to occur off Mexico, making it the most important survey of deep-sea Ophiuroidea carried out in western Mexico to date.

This paper presents a checklist of echinoderm species in the Adriatic Sea. The checklist is based on the review of the available literature data, with temporal coverage from the end of the 18th century to the present day, including the most recent investigations of benthic communities. A total of 108 species have been recorded: 2 species from class Crinoidea, 23 species from class Asteroidea, 22 species from class Ophiuroidea, 22 species from class Echinoidea and 39 species from class Holothuroidea. Non-indigenous echinoderm species have not been observed.

The taxonomy of some ophiuroids reported from off Argentina, western Antarctica and the SW Atlantic Ocean is reviewed. The species Amphilepis sanmatiensis, known only from the small holotype, is a synonym of Amphioplus lucyae. This synonymy removes the only reported endemic ophiuroid from Argentina. The species name ?Ophiacantha ingrata Koehler, 1923? used for specimens from South Georgia is invalid; the specimens are likely to belong to one of two cryptic species within the O. vivipara complex. Specimens of Amphiura joubini reported from Argentina are re-identified as Amphiura princeps, and specimens of Ophiactis amator from the Antarctic Peninsula are re-identified as Ophiactis asperula. Fil: Brogger, Martin Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentina Fil: O'hara, Timothy D.. Museum Victoria; Australia

Lateral arm plates, the spine-bearing plates of the ophiuroid arm skeleton, have long been assumed to display sufficient morphological diversity to be used for species identifications in ophiuroid micropalaeontology. As a consequence, many new brittle-star species have been described on the basis of isolated fossil lateral arm plates. A substantial lack of information on the morphological variability of lateral arm plates in respect of taxon concepts, however, has led to increasing confusion over species limits and excessive extensions of stratigraphic species ranges. In this study, we therefore performed a detailed assessment of the variability of lateral arm plate morphology within and between species in order to test to what extent isolated lateral arm plates can be used for species identifications. To this end, we investigated the morphological variability of lateral arm plates within species according to ontogenetic changes and according to the position of the plates along the arm. Furthermore, we examined the lateral arm plates of 56 Recent species, belonging to 27 genera and 10 families, and systematically assessed their morphology in the light of currently accepted taxon concepts. The results of this study demonstrate that lateral arm plate morphology is in accordance with most family, genus and species limits. Some of the currently accepted taxon concepts, including the affinities between the Ophiacanthidae and Ophiocomidae, however, are challenged by lateral arm plate morphology. Differences in lateral arm plate morphology between taxa are the most conspicuously displayed by adult proximal lateral arm plates, as a consequence of their high degree of differentiation compared to distal or juvenile lateral arm plates. Differences at species level, often pertain to characters which were considered to be within-species variation in previous micropalaeontological works, suggests that species identifications based on isolated fossil lateral arm plates require a much more detailed and careful morphological assessment. Some of the species studied herein displayed indistinguishable lateral arm plate morphologies, but belonged to the same genus in all cases. Our study endorses the use of isolated fossil lateral arm plates for taxonomic interpretations in ophiuroid micropalaeontology, including species identifications and the creation of new taxa, providing that descriptions are based on pristinely preserved adult proximal LAPs, described and illustrated using SEM-pictures of both the external and internal sides of the plate.