Three new meiobenthic species from a submarine cave in Japan: Echinoderes gama, E. kajiharai and E. uozumii (Kinorhyncha: Cyclorhagida)

Abstract

Three new species of echinoderid kinorhynchs are described from Daidokutsu, a submarine cave in Ryukyu Islands, Japan. Echinoderes gama sp. nov. is characterized by the presence of middorsal acicular spines on segments 4–8; lateroventral acicular spines on segments 7–9; lateroventral tubes on segment 5; sublateral tubes on segment 8; laterodorsal tubes on segment 10; and type-2 gland cell outlets in subdorsal and lateroventral position on segment 2. Echinoderes kajiharai sp. nov. is defined by the presence of middorsal acicular spines on segments 4, 6, 8; lateral accessory acicular spines on segment 9; lateroventral acicular spines on segments 6–8; lateroventral tubes on segments 2 and 5; midlateral tubes on segment 10; and type-2 gland cell outlets in laterodorsal position on segments 2 and 5, and subdorsal position on segments 8 and 9. Echinoderes uozumii sp. nov. is characterized by the presence of middorsal acicular spines on segments 4 and 6; lateroventral acicular spines on segments 6–9; lateroventral tubes on segments 2 and 5; sublateral tubes on segment 8; laterodorsal tubes on segment 10; type-2 gland cell outlets in subdorsal and lateral accessory position on segment 2; and blunt, short pectinate fringe teeth of primary pectinate fringe on segment 1. In addition, the Echinoderes multiporus species group including E. kajiharai sp. nov., and the Echinoderes bispinosus species group including E. uozumii sp. nov. are established. Furthermore, the distribution of the two species groups and the origin of Echinoderes species in Daidokutsu are discussed.

Echinoderes (Kinorhyncha: Cyclorhagida) from the Hikurangi Margin, New Zealand

“…The spine pattern on its dorsal side, with middorsal spines on segments 4 and 6, is already an uncommon feature within Echinoderes. This trait itself is shared only with E. astridae Sørensen, 2014, E. bispinosus Higgins, 1982, E. uozumii Yamasaki et al, 2020 described below in the present study (Higgins 1982;Sørensen 2014;Yamasaki et al 2020b). This character in combination with its tubes on segment 2 makes E. landersi unique among its congeners.…”

Description, redescription and revision of sixteen putatively closely related species of Echinoderes (Kinorhyncha: Cyclorhagida), with the proposition of a new species group – the Echinoderes dujardinii group

“…The three most common echinoderid dorsal patterns of glandular cell outlets type 1 on segments 1 to 9. Literature sources: Huys & Coomans 1989;Adrianov & Malakhov 1999;Adrianov et al, 2002a;Neuhaus & Blasche 2006;Herranz et al , 2014Herranz et al , 2018Sørensen et al 2012Sørensen et al , 2013Sørensen et al , 2016Sørensen et al , 2018Herranz & Pardos 2013;Sørensen & Landers 2014;Pardos et al 2016b;Yamasaki & Durucan, 2018;Yamasaki et al 2018aYamasaki et al , 2018bYamasaki et al , 2020bCepeda et al 2019bCepeda et al , 2019cGrzelak & Sørensen 2019;Sánchez et al 2019;Yamasaki & Dal Zotto 2019; present study. always present in middorsal positions on segments 1 to 3, and in subdorsal positions on segments 4 to 9.…”