The family Apseudidae Leach, 1814 (Crustacea: Tanaidacea) in the Gulf of Gabès (Mediterranean Sea): taxonomic and biogeographic remarks and description of Apseudopsis gabesi Esquete sp. nov.

Abstract

Species of Apseudidae Leach, 1814 are often found in high numbers in benthic samples and represent an important element of the infaunal assemblages of the coasts of the NE Atlantic and Mediterranean Sea. Precise knowledge of the species diversity, as well as accurate identification tools, is a need for obtaining reliable conclusions from benthic ecological studies and environmental assessment surveys. During a benthic survey carried out in the Gulf of Gabes (Tunisia), one Apseudes Leach, 1814 and four Apseudopsis Norman, 1899 species were identified, including one species new to science. Apseudopsis gabesi Esquete sp. nov. is distinguished from other species of the genus for having double ventral apophyses on pereonite 2, pereonites 2–6 with lateral indentations, ventral protuberances on antennule peduncle articles 2 and 3, three ventral spines on pereopod 1 propodus and no spine on merus. A ventral apophyse on cephalothorax is a newly recorded taxonomic character for Apseudopsis mediterraneus (Băcescu, 1961). Apseudopsis annabensis (Guţu, 2002) and Apseudopsis ostroumovi Băcescu and Cărăusu, 1947 are new records for Tunisian waters. Additionally, we comment on the taxonomic characters allowing the identification of the species and the diagnosis of the genus and propose the original name to Apseudes robustus Sars, 1882, and Apseudes israeliticus (Băcescu, 1961) comb. nov. is herein accepted and elevated to species rank. Additionally, the presence of abnormal numbers of spines on pereopod 1 propodus is discussed. The distribution of the Apseudopsis in the Mediterranean Sea is commented.