Echinoderes cyaneafictus, Cepeda & González-Casarrubios & Sánchez & Spedicato & Michaud & Zeppilli, 2022

Cepeda, Diego, González-Casarrubios, Alberto, Sánchez, Nuria, Spedicato, Adriana, Michaud, Emma & Zeppilli, Daniela, 2022, Two new species of mud dragons (Scalidophora: Kinorhyncha) inhabiting a human-impacted mangrove from Mayotte (Southwestern Indian Ocean), Zoologischer Anzeiger 301, pp. 23-41 : 25-29

publication ID	https://doi.org/ 10.1016/j.jcz.2022.09.001
persistent identifier	https://treatment.plazi.org/id/616487EB-FFFF-7759-FCA4-CDF8CE5BF937
treatment provided by	Felipe
scientific name	Echinoderes cyaneafictus
status	sp. nov.

Treatment

3.1. Echinoderes cyaneafictus View in CoL sp. nov

Zoobank code: urn:lsid:zoobank.org:act:AD7E82A4-F389-485E-8B7B-2E53437B09C1

( Figs. 2–4 View Fig View Fig View Fig , Tables 2 and 3)

3.1.1. Material examined

Holotype, adult male, collected on October 6th, 2018, at Chirongui Bay , Grande-Terre Island, Mayotte Archipelago, SW Indian Ocean: 12 Ǫ 55 ′ 17.5 ′′ S, 45 Ǫ 09 ′ 10.4 ′′ E 12 Ǫ 55 ′ 22.8 ′′ S, 45 Ǫ 09 ′ 09.1 ′′ E in black organic mud at the intertidal zone; mounted in Fluoromount G ®, deposited at MNHN under catalogue number: 623 Ma . Paratypes, 23 adult males and 14 adult females, same collecting data as holotype; mounted in Fluoromount G ®, deposited at MNHN under catalogue numbers: 587 Ma-589 Ma, 594 Ma-595 Ma, 597 Ma-599 Ma, 601 Ma- 606 Ma, 608 Ma-612 Ma, 614 Ma, 616 Ma, 618 Ma-620 Ma, 622 Ma, 626 Ma-628 Ma and 630 Ma-636 Ma. Additional, non-type material : 12 juveniles, same collecting data as holotype and paratypes; mounted in Fluoromount G ®, deposited at MNHN under catalogue numbers: 590 Ma-593 Ma, 596 Ma, 600 Ma, 607 Ma, 615 Ma, 617 Ma, 621 Ma and 624 Ma-625 Ma .

3.1.2. Diagnosis

Echinoderes with spines that are short, poorly sclerotized and weakly articulated in middorsal position on segment 4 and sublateral position on segments 6–7, plus large tubes in lateroventral position on segment 5, lateral accessory position on segment 8 and laterodorsal position on segment 10. Enlarged, oval sieve plate openings in sublateral position on segment 9, consisting of an anterior, slightly convex region bearing numerous pores, and a posterior, slightly concave area bearing a single pore.

3.1.3. Etymology

The species name derives from Cyanea P´eron & Lesueur, 1810, which is a genus of scyphozoan cnidarians characterized by having multiple, elongated tentacles (resembling the elongated hairs of the segment 1 sensory spots of the species) and the Latin fictus (meaning feigned, false, counterfeit).

3.1.4. Description

See Table 2 for measurements of selected morphological traits and dimensions, and Table 3 for summary of acicular spine, tube, nephridiopore, glandular cell outlet and sensory spot locations.

Head: only a few specimens were found with a completely everted head, hence only a few details in some structures can be provided. Ring 00 of mouth cone with nine outer oral styles alternating in size between slightly larger and smaller ones. Outer oral styles composed of two jointed subunits: a rectangular, basal piece with proximal fringed sheath bearing a tuft of 5–7 spinous processes; and a triangular, hooked, distally pointed and curved end-piece ( Fig. 3F View Fig ). Triangular, strongly sclerotized, basally fringed cuticular thickenings flanking the outer oral styles. Outer oral styles located anterior to each introvert sector, except in the middorsal sector 6.

Introvert with six rings of scalids (one ring of primary spinoscalids and five rings of regular-sized scalids) and 10 longitudinal sectors delimited by the arrangement of the primary spinoscalids. Ring 01 of introvert with 10 primary spinoscalids, larger than remaining ones, laterally compressed, composed of a medially fringed basal sheath and a distal, elongated, flexible, distally blunt end-piece ( Fig. 3F View Fig ). Remaining rings of introvert with regular-sized scalids, composed of a rectangular basal sheath and a distal, elongated, acicular, distally pointed end-piece ( Fig. 3F View Fig ). Scalids tend to collapse when mounted for LM ( Fig. 3F View Fig ), and specimens for SEM were not available, so details on the scalid arrangement are not provided.

Neck: 16 trapezoidal placids, wider at base, closely adjacent, with distinct joint between the neck and first trunk segment. Midventral placid widest (ca. 9–10 μm wide at base), remaining ones slightly narrower (ca. 6–8 μm wide at base). A ring of six long, superficially haired trichoscalids associated with the placids, attached to large, bottleshaped trichoscalid plates ( Fig. 2A–B View Fig , D-E; 3B, D, F).

Trunk: fusiform, composed of 11 segments, heart-shaped in cross-section. Segments 1–2 closed, ring-like cuticular plates, remaining ones with one tergal and two sternal cuticular plates ( Fig. 2A–B View Fig , D-E; 3A; 4A). Maximum sternal width at segment 7, trunk progressively tapering toward anterior and posterior ends. Cuticular hairs throughout segments 2–10, emerging from rounded to slightly oval perforation sites. Cuticular hairs arranged as 6–8 approximately straight transversal rows densely covering the cuticular surface of segment 2; as 5–7 transversal, uninterrupted rows that become wavy at laterodorsal, sublateral and ventrolateral to ventromedial regions on segment 3; as 7–12 transversal rows interrupted at the laterodorsal region that become wavy at sublateral and ventrolateral to ventromedial regions on segments 4–10; segments 1 and 11 without hairs ( Fig. 2A–E View Fig ; 3 View Fig B-D; 4B-F). Posterior segment margins straight, with a long, conspicuous, strongly serrated primary pectinate fringe ( Fig. 2A–E View Fig ; 3 View Fig B-C; 4B-F). Secondary pectinate fringes not detected.

Segment 1: type 1 glandular cell outlets in middorsal and lateroventral positions, the former near the anterior segment margin, the latter located at the anterior half of the segment ( Fig. 2A–E View Fig ; 3B View Fig ). Rounded sensory spots (sensu Lundbye et al., 2011) in subdorsal, laterodorsal and ventrolateral positions, the former two located near the anterior segment margin, the latter located near the posterior segment end; these sensory spots are characterized by having the posterior part of the papillae area with a transversal row of conspicuously elongated hairs ( Fig. 2A–B View Fig , D-E; 3 B, D, E).

Segment 2: type 1 glandular cell outlets in middorsal and ventromedial positions ( Fig. 2A–B View Fig , D-E; 3D). Droplet-shaped sensory spots (sensu Lundbye et al., 2011) in middorsal position only in males, in paradorsal and midlateral positions only in females, and also in subdorsal and laterodorsal positions in both sexes ( Fig. 2A–B View Fig , D-E; 3B).

Segment 3: type 1 glandular cell outlets in middorsal and ventromedial positions ( Fig. 2A–B View Fig , D-E; 3D). Droplet-shaped sensory spots in middorsal and subdorsal positions, and also in midlateral position only in females ( Fig. 2B View Fig , D-E).

Segment 4: short (ca. 4–10 μm long), poorly sclerotized, weakly articulated, acicular spine in middorsal position ( Fig. 2B View Fig ; 3 B View Fig ). Type 1 glandular cell outlets in paradorsal and ventromedial positions ( Fig. 2A–B View Fig ).

Segment 5: tubes in lateroventral position ( Fig. 2A View Fig ; 3C View Fig ). Type 1 glandular cell outlets in paradorsal and ventromedial positions ( Fig. 2A–B View Fig ; 4B View Fig ). Droplet-shaped sensory spots in subdorsal, midlateral and ventromedial positions ( Fig. 2A–B View Fig ; 3C View Fig ; 4B View Fig ).

Segment 6: short (ca. 4–7 μm long), poorly sclerotized, weakly articulated, acicular spines in sublateral position ( Fig. 2A View Fig ; 3C View Fig ). Type 1 glandular cell outlets in paradorsal and ventromedial positions ( Fig. 2A–B View Fig ; 4B View Fig ). Droplet-shaped sensory spots in subdorsal, midlateral and ventromedial positions, the former slightly more mesial than those of the precedent segment but still in subdorsal position ( Fig. 2A–B View Fig ; 3C View Fig ; 4B View Fig ).

Segment 7: similar to segment 6 in the arrangement of spines, glandular cell outlets and sensory spots ( Fig. 2A–B View Fig ; 3C View Fig ; 4B View Fig ).

Segment 8: tubes in lateral accessory position ( Fig. 2A View Fig ; 3C View Fig ). Type 1 glandular cell outlets in paradorsal and ventromedial positions ( Fig. 2A–B View Fig ; 4 View Fig B-C). Droplet-shaped sensory spots in paradorsal and ventrolateral positions ( Fig. 2A–B View Fig ; 4 View Fig B-C).

Segment 9: type 1 glandular cell outlets in paradorsal and ventromedial positions ( Fig. 2A–B View Fig ; 4C View Fig ). Droplet-shaped sensory spots in paradorsal, subdorsal and ventrolateral positions ( Fig. 2A–B View Fig ; 4C View Fig ). Nephridiopores in sublateral position as oval, enlarged sieve plate openings consisting of an anterior, elongated, slightly convex area with numerous pores, and a posterior, slightly concave region with a single pore (sensu Lundbye et al., 2011) ( Fig. 2A View Fig ; 4F View Fig ).

Segment 10: tubes in laterodorsal position ( Fig. 2B View Fig ). Two longitudinally aligned type 1 glandular cell outlets in middorsal position; type 1 glandular cell outlets also in ventromedial position ( Fig. 2A–C View Fig ; 4C, E View Fig ). Droplet-shaped sensory spots in subdorsal and ventrolateral positions ( Fig. 2A–C View Fig ; 4C, E View Fig ). Posterior margins of sternal plates midventrally extended, forming an elongated, V-shaped extension over the following segment ( Fig. 2A View Fig ; 4 View Fig D-E).

Segment 11: relatively short lateral terminal spines (LTS:TL average ratio = 23.8%), apparently well sclerotised but still quite flexible, distally pointed, with a hollow central cavity ( Fig. 2A–C View Fig ; 3A View Fig ; 4A View Fig , D-E). Males with three pairs of penile spines, dorsal and ventral pairs longer and slender, smooth and distally rounded, medial pair shorter and stouter, hairy with a distal tuft of hairs ( Fig. 2A–B View Fig ; 4E View Fig ); females with short (LTAS:LTS average ratio = 5.0%), slender, occasionally distally frayed, lateral terminal accessory spines ( Fig. 2C View Fig ; 4D View Fig ). Type 1 glandular cell outlet in middorsal position ( Fig. 2B–C View Fig ). Rounded sensory spots in subdorsal and ventromedial positions, the latter near the basal insertion of the lateral terminal spines ( Fig. 2A–C View Fig ; 4E View Fig ). Tergal extensions forming projections laterally, with blunt tips in males and pointed tips in females; posterior margin between the tergal extensions densely fringed ( Fig. 2A–C View Fig ; 4 View Fig D-E). Sternal extensions short, distally rounded ( Fig. 2A View Fig ; 4E View Fig ).

3.1.5. Remarks

The holotype of the species (MNHN-623 Ma) was found carrying epibiont, filamentous bacteria attached to the lateral margins of segment 11 tergal plate ( Fig. 3A View Fig ).