Echinoderes imperforatus Higgins, 1983

Sørensen, Martin V., Goetz, Freya E., Herranz, María, Chang, Cheon Young, Chatterjee, Tapas, Durucan, Furkan, Neves, Ricardo C., Yildiz, N. Özlem, Norenburg, Jon & Yamasaki, Hiroshi, 2020, 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, European Journal of Taxonomy 730, pp. 1-101 : 26-28

Echinoderes imperforatus Higgins, 1983

Fig. 7

Emended diagnosis

Echinoderes with short middorsal spines on segments 4 to 8, and lateroventral spines on segments 6 to 9, never extending beyond the posterior margin of their respective segments. Tubes present in lateroventral positions on segments 2 and 5, and in laterodorsal positions on 10. Minute glandular cell outlets type 2 in laterodorsal positions on segments 8 and 9. Tergal extensions of segment 11 short, pointed and well-spaced; sternal extensions short with ventrolateral seta-like tuft of extended fringe tips. Females with ventromedial female papillae resembling glandular cell outlets type 2 on segments 6 to 8. Trunk segments with cuticular hairs, but perforation sites are indistinct.

Material examined

Holotype

BELIZE • 1 ♀; Carrie Bow Cay ; 16°50′ N, 088°06′ W; 14 m b.s.l.; 8 Apr. 1977; R.P. Higgins leg.; RH 442, fine coral sand with mangrove and seagrass detritus; USNM-69972 . Specimen mounted for LM. Paratypes

BELIZE – Carrie Bow Cay • 1 ♀; same collection data as for holotype; USNM-69974 • 1 ♀, 1 ♂; 500 m southwest of type locality; 3 m b.s.l.; 8 Apr. 1977; R.P. Higgins leg.; RH443, coralline mud with mangrove and seagrass detritus; USNM-69975 • 1 ♀; 500 m south of RH443; 3 m b.s.l.; 8 Apr. 1977; R.P. Higgins leg.; RH444, very fine coralline mud with mangrove and seagrass detritus; USNM-69976 .

All specimens mounted for LM. See Table 1 for an overview.

Description

The appearance of the species generally follows the description provided by Higgins (1983), hence the following notes only provide additional information not included in the original description.

Introvert with six trichoscalids attached to trichoscalid plates (four dorsal and two ventral). Tubes present in lateroventral positions on segments 2 and 5 ( Fig. 7C, E ), and in laterodorsal positions on segment 10 ( Fig. 7 G–H). Spines are present in middorsal positions on segments 4 to 8 ( Fig. 7D ), and lateroventral positions on segments 6 to 9 ( Fig. 7E ); spines never extend beyond the posterior margins of their respective segments. Sensory spots could not be observed on all segments, but it is positively confirmed that sensory spots are present in following positions: paradorsal positions on segments 6 to 8, subdorsal positions on segments 4 to 9 ( Fig. 7F ), and ventromedial positions on segment 1. Glandular cell outlets type 1 are present in following positions: middorsal position on segments 1 to 3 ( Fig. 7B ), subdorsal positions on segments 4 to 9 (closer to paradorsal positions on segment 9) ( Fig. 7B, D, F ), lateroventral positions on segment 1 ( Fig. 7C ), and ventromedial positions on segments 2 to 10 ( Fig. 7C, E ). Minute glandular cell outlets type 2 present in laterodorsal positions on segments 8 and 9 ( Fig. 7F ). Females with ventromedial female papillae in ventromedial positions on segments 6 to 8 ( Fig. 7E ); outlet of papillae on segments 6 and 7 close to the ventrolateral positions, whereas outlets on segment 8 are closer to the midventral line. The intracuticular structures of the papillae on segment 6 form a semicircle with a small protuberance in the curved part of the structure; substructure of segment 7 and 8 papillae forms very short intracuticular tubes. Tergal extensions triangular and well-spaced ( Fig. 7 G–H). Posterior margins of sternal plates of terminal segment obliquely straight towards a ventrolateral point; pectinate fringe well-developed, with differentiated fringe tips forming seta-like extensions ( Fig. 7G ). Perforation sites of cuticular hairs are not invisible on most segments, however, they can be visualized as indistinct dots on segments 1 and 2.

Figures

Fig. 7. Light micrographs showing overviews and details of Echinoderes imperforatus Higgins, 1983. A, D–E. Holotype, ♀ (USNM-69972). B, F, H. Paratype, ♀ (USNM-69974). C, G. Paratype, ♂ (USNM-69975). A. Ventral overview. B. Segments 1 to 3, dorsal view. C. Segments 1 to 3, ventral view. D. Segments 4 to 8, dorsal view. E. Segments 4 to 8, ventral view, showing female sexual dimorphism. F. Segments 8 to 10, dorsal view. G. Segments 10 to 11, ventral view, showing male sexual dimorphism. H. Segments 10 to 11, ventral view, showing female sexual dimorphism.