Two new species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Gulf of Mexico

Abstract

Comprehensive sampling of meiofauna along the northern continental slope in the Gulf of Mexico has revealed a diverse kinorhynch fauna of undescribed species. The present contribution includes the description of two new species of the cyclorhagid genus Echinoderes. Echinoderes augustae sp. nov. is recognized by the presence of acicular spines in middorsal positions on segments 4-8, and in lateroventral positions on segments 6-9, tubes in lateroventral positions on segments 2-5, midlateral positions on segment 4, and in sublateral positions on segment 8. It furthermore has glandular cell outlets type 2 in subdorsal positions of segment 2, a middorsal protuberance-like extension from the intersegmental border between segments 10 and 11, and conspicuously short and stout lateral terminal spines. Echinoderes skipperae sp. nov. has acicular spines in middorsal positions on segments 4, 6, and 8, and in lateroventral positions on segments 8 and 9, tubes in sublateral and ventrolateral positions on segment 2, in lateroventral positions on segment 5, in lateral accessory positions on segment 8, and in laterodorsal positions on segment 10. The species can furthermore be recognized by its conspicuously well-developed pachycycli at the anterior segment margins of segments 2 to 10, and margins of sternal plates facing the midsternal junctions of segments 3 to 10.

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

“…Higgins (1964) also mentions the presence of a middorsal protuberance, emerging between segments 10 and 11. A structure like this has also been described from E. augustae Sørensen and Landers, 2014, and it might also be present in E. eximus. However, its presence in the latter species needs to be confirmed by more careful examinations with SEM (see Sørensen and Landers, 2014).…”

“…The occurrence and positions of glandular cell outlets type 2 were only relatively recently introduced as taxonomic characters among echinoderids. Neuhaus and Blasche (2006) used the character to distinguish between species of Fissuroderes, and subsequently the occurrence of the outlets have proved useful to discriminate species of Meristoderes and Echinoderes also (see e.g., Herranz et al, 2012;Sørensen et al 2012;Yamasaki and Kajihara 2012;Herranz and Pardos 2013;Sørensen 2014;Sørensen and Landers 2014;Yamasaki and Fujimoto 2014). Information on the distribution of glandular cell outlets type 2 might be missing in older descriptions, but as part of the present project, a considerable part of the Echinoderes types stored at the Smithsonian Institution were examined, and this study confirmed that 1) glandular cell outlets type 2 appear in many species even though it is not reported in the literature, and 2) the outlets of this type do not appear to show intraspecific variation in their occurrence, which supports the taxonomic value of the character.…”

First account on kinorhynchs from Portugal, with the description of two new species: Echinoderes lusitanicus sp. nov. and E. reicherti sp. nov.

“…The two species share the same tube/spine distribution in the lateral series, and E. lusitanicus sp. nov. also shows, at least to some extent, the same rectangular overall trunk shape that is highly characteristic for E. skipperae (Sørensen & Landers 2014). However, the new species does not have the conspicuously strong pachycycli that are found in E. skipperae, and the dorsal spine patterns are also different, since E. lusitanicus sp.…”

“…No other kinorhynch shows this particular tube/spine pattern. The presence of lateroventral tubes and/or spines on only segments 5, 8 and 9 is shared with four other species only: Echinoderes caribiensis Kirsteuer, 1964 Lou, 1934(see Kirsteuer 1964Higgins & Kristensen 1988;Sørensen et al 2012;Sørensen & Landers 2014). Echinoderes caribiensis is a shallowwater species from mangroves in Venezuela (Kirsteuer 1964), and it possesses lateroventral tubes or spines on segments 5, 8 and 9, but since it otherwise does not have any spines on segments 1 to 10, it cannot in any way be confused with E. lusitanicus sp.…”

Redescription of Echinoderes levanderi Karling, 1954 (Kinorhyncha: Cyclorhagida) – a kinorhynch tolerant to very low salinities

“…The presence of sublateral tubes on segment 4 is unique among congeners and the only other species with tubes on segment 4, but in the midlateral positions, is E. augustae Sørensen & Landers, 2015(Sørensen & Landers 2014. However, E. augustae is easily distinguished from E. levanderi by its short, stout lateral terminal spines.…”