A new species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Gulf of Mexico, with a redescription of Echinoderes bookhouti Higgins, 1964

Sampling of meiofauna along the US continental shelf of the Gulf of Mexico has been carried out in an eight year period, from 2007 to 2014. Studies of the kinorhynch fauna from these collections have resulted in the description of two new species, Echinoderes augustae and E. skipperae. The present contribution includes new recordings of E. augustae and E. skipperae, as well as information on two additional kinorhynch species, Echinoderes bookhouti and Echinoderes charlotteae sp. nov. The latter species is new to science and a detailed morphological description is provided. Echinoderes bookhouti was originally described from shallow water localities off North Carolina, but comparison with the type material indicates that the same species occurs in the Gulf of Mexico. Based on the new material from the Gulf, E. bookhouti is redescribed using light- and scanning electron microscopy, and new taxonomically significant characters are provided. In addition, examination of other Echinoderes types from the collections of the Smithsonian Institution revealed that several species described before 1990 showed taxonomically significant structures, such as tubes and glandular cell outlets type 2, which were not included in their original descriptions. Hence, to ease future identification of Echinoderes species, we provide updated information about the nature and distribution of cuticular structures for a total of seven species, including E. abbreviatus, E. andamanensis, E. imperforatus, E. kristenseni, E. pennaki, E. truncatus, and E. wallaceae.