Echinoderes gerardi Higgins, 1978

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 : 21-22

Echinoderes gerardi Higgins, 1978

Figs 5–6 , Tables 4, 6

Echinoderes gerardi Higgins, 1978: 172–176 , figs 1–8.

Echinoderes gerardi – Dal Zotto & Todaro 2016: 132–134, 138, table 6.

E. dujardinii – Mari & Morselli 1987: 117. — Sánchez-Tocino et al. 2011: 179–184, figs 1–4, tables 1–2. — Sánchez et al. 2012: 26 [Algeciras, Granada, Murcia, Alicante]. — Ürkmez et al. 2016: 1–8, figs 2–4.

Echinoderes aff. gerardi – Sönmez et al. 2016: 8–9, figs 1–2.

Emended diagnosis

Echinoderes with very short middorsal spines on segments 4 to 8 not even reaching the pectinate fringes of posterior segment margins; middorsal spines on segments 4 to 7 lanceolate, i.e., narrower proximally and distally than medially, whereas middorsal spine on segment 8 is more parallel-sided and only narrowing distally. Lateroventral spines on segments 6 to 9. Tubes present in lateroventral positions on segments 2 and 5, in lateral accessory positions on segment 8, and in laterodorsal positions on 10. Minute glandular cell outlets type 2 in laterodorsal positions on segments 8 and 9; outlets on segment 9 anterior to laterodorsal sensory spots. 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.

Material examined

Holotype

TUNISIA • 1 ♀; Gulf of Tunis , Korbous ; 36°49′ N, 010°34′ E; 0 m b.s.l.; Dr K. Ruetzler leg.; choanocytes of the sponge Tethya aurantium (see Higgins 1978); USNM-54841 . Specimen mounted for LM.

Additional material

TURKEY – Aegean Coast of Turkey • 3 ♀♀, 3 ♂♂; K̹ç̹kb̹k; 37°08′27″ N, 027°21′28″ E; 0 m b.s.l.; 23 Oct. 2012; Sönmez and S. Sak leg.; intertidal macroalgae; NHMD-616808 to 616813 • 4 ♀♀, 1 ♂; Akbük Sonrası ; 37°23′59″ N, 027°22′10″ E; 0 m b.s.l.; 24 Oct. 2012; Sönmez and S. Sak leg.; intertidal macroalgae; NHMD-616814 to 616818 • 1 ♀; Öncesi ; 37°59′40″ N, 027°07′15″ E; 0 m b.s.l.; 25 Oct. 2012; Sönmez and S. Sak leg.; intertidal macroalgae; NHMD-616819 • 1 ♀, 1 ♂; Çalış; 36°39′33″ N, 029°06′35″ E; 0 m b.s.l.; 16 May 2012; Sönmez and S. Sak leg.; intertidal sand from type locality of Cephalorhyncha flosculosa Yildiz et al., 2016 (see Yildiz et al. 2016); NHMD-616820 to 616821 • 3 ♀♀, 1 ♂; Çatal Island ; 37°00′24″ N, 027°13′06″ E; 0 m b.s.l.; 17 June 2011; N. Özlem Yıldız leg.; intertidal macroalgae; personal reference collection of the first author. – Antalya Coast of Turkey • 7 ♀♀, 5 ♂♂; Antalya , Bilem Beach ; 36°51′17″ N, 030°44′38″ E; 3 m b.s.l.; 20 Oct. 2012; F. Durucan leg.; red algae ( Laurencia obtusa ) on sandy bottom at type locality of Echinoderes antalyaensis Yamasaki & Durucan, 2018 (see Yamasaki & Durucan 2018); personal reference collection of the last author .

SPAIN – Andalusian Atlantic south coast of Spain • 2 ♀♀, 1 ♂; Cadiz; F. Pardos leg.; UCM • 2 ♀♀, 1 ♂; slightly west of the Gibraltar Strait, Algeciras ; F. Pardos leg.; UCM. – Spanish Territory on African mainland at the Gibraltar Strait • 3 ♀♀, 3 ♂♂; Ceuta; F. Pardos leg.; UCM. – Andalusian Mediterranean south coast of Spain • 1 ♀; Málaga ; F. Pardos leg.; UCM • 1 ♀; Almería ; F. Pardos leg.; UCM.– Murcian Mediterranean southeast coast of Spain • 1 ♀, 2 ♂♂; Cabo de Palos ; F. Pardos leg.; UCM. – Valencian Mediterranean east coast of Spain • 1 ♂; Denia ; F. Pardos leg.; UCM .

All Spanish and Turkish Aegean specimens mounted for LM; all Turkish specimens from Antalya mounted for SEM. See Table 1 for an overview.

Description

Measurements of spine and segments length and dimensions were made on the Turkish and Spanish specimens. They are presented separately and summarized together with the original measurements of the type material in Table 6 . LM and SEM examinations of E. gerardi revealed that it is morphologically very similar with E. dujardinii . Positions of cuticular structures, i.e., spines, tubes, most sensory spots and glandular cell outlets ( Figs 5 A–H, 6A–F, I–K) followed the pattern observed in E. dujardinii , hence, the distribution of these structures is summarized in the same table (see Table 4). The only observed difference in distribution of sensory spots regarded the ventrolateral sensory spots on segment 10, that in E. dujardinii are restricted to males, but occur in both sexes in E. gerardi ( Fig. 6 J–K). Since the The middorsal spines in E. gerardi are extremely short, and never even reaching the pectinate fringes of the posterior segment margins ( Figs 5 B–D, F–G, 6D). Opposite to typical acicular spines, the middorsal spines in E. gerardi are tapered at their attachment point, broadest around ⅓ from proximal end, and then gradually tapering from this point towards the tip, giving them a lanceolate appearance ( Figs 5 F–G, 6D). Female papillae are present on sternal plates of segments 6, 7 and 8 ( Figs 5E , 6 F–H), and have the same intracuticular structure as described from E. dujardinii . However, while the position of the papillae in E. dujardinii appeared to be rather fixed within the centre of the ventromedial area, the position on segment 6 in E. gerardi varied from centred ventromedial to a much more lateral position, very close to the ventrolateral line. But other than this, the morphology is very similar with the one in E. dujardinii , including the presence of laterodorsal glandular cell outlets type 2 on segments 8 and 9 ( Figs 5F , 6I ). The only other differences are meristic (see Tables 3 and 6 , and Discussion).

Figures

Fig. 5. Light micrographs showing overviews and details of of Echinoderes gerardi Higgins, 1978. A, F. Holotype, ♀ (USNM-54841). B–E, G–H. ♀, non-type from Turkey (NHMD-616810). A. Ventral overview. B. Segments 1 to 6, dorsal view. C. Segments 1 to 4, ventral view. D. Segments 5 to 9, dorsal view. E. Segments 6 to 8, ventral view, showing female sexual dimorphism. F. Segments 8 to 9, dorsal view. G. Detail of segments 7 to 8 showing middorsal spines. H. Segments 10 to 11, ventral view, showing female sexual dimorphism.

Fig. 6. Scanning electron micrographs showing overviews and details of Echinoderes gerardi Higgins, 1978. A–C, E, K. ♂ (HY, personal reference collection). D, F–J. ♀ (HY, personal reference collection). A. Lateral overview. B. Segments 1 to 2, dorsal view. C. Segments 1 to 2, ventrolateral view. D. Segments 5 to 8, subdorsal view. E. Segments 5 to 7, lateral view. F. Segments 6 to 8, showing female sexual dimorphism. G. Detail of segment 6 showing lateroventral spine and female papilla. H. Detail of segment 7 showing lateroventral spine and female papilla. I. Segments 8 to 9 lateral view. J. Segments 10 to 11 ventral view, showing female sexual dimorphism. K. Segments 9 to 11 ventral view, showing male sexual dimorphism.