Deep-water Asteroidea (Echinodermata) collected during the TALUD cruises in the Gulf of California, Mexico

Abstract

During a series of cruises aboard the R/V "EI Puma" aimed at collecting the deep-water benthic and pelagic fauna off the Pacific coast of Mexico, in the eastern Pacific, samples of Asteroidea were collected below 500 m depth (587-1 526 m). A total of 335 specimens were collected, belonging to 18 species, 14 identified to species, 3 to genus, and 1 previously undescribed species. New records are provided for Dipsacaster laetmophilus Fisher, 1910, Myxoderma sacculatum (Fisher, 1905), Peribolaster biserialis Fisher, 1905, Ampheraster chiroplus Fisher, 1928, Ampheraster hyperoncus (H. L. Clark, 1913), Anteliaster coscinactis Fisher, 1923, Nearchaster aciculosiis (Fisher, 1910), Ceramaster leptoceramus (Fisher, 1905), Mediaster transfuga Ludwig, 1905, and Lophaster furcilliger Fisher, 1905. All species were collected below the oxygen minimum zone that extends throughout the central and southern Gulf of California, or within the threshold zone where severe to mild hypoxic conditions prevail. Epibenthic dissolved oxygen concentrations associated with the capture of the specimens show support for strong tolerance to severe hypoxia (<1.0 ml O2/l) for most species, but only mild hypoxia for Ctenodiscus crispatus (Retzius, 1805), and Nymphaster diomedeae Ludwig, 1905. A checklist of all species of Asteroidea occurring below 500 m depth off the Pacific coast of Mexico is included.