Echinoderes guianensis, Cepeda & Gayet & Spedicato & Michaud & Zeppilli, 2022

Cepeda, Diego, Gayet, Nicolas, Spedicato, Adriana, Michaud, Emma & Zeppilli, Daniela, 2022, Two new species of the Echinoderes coulli-group (Kinorhyncha: Cyclorhagida: Echinoderidae) from a low human-impacted mangrove swamp in French Guiana (western Atlantic Ocean), Zoologischer Anzeiger 301, pp. 179-195 : 186-189

publication ID	https://doi.org/ 10.1016/j.jcz.2022.10.008
DOI	https://doi.org/10.5281/zenodo.10374760
persistent identifier	https://treatment.plazi.org/id/AE098789-C672-FF8D-2604-F9C77BFDF89B
treatment provided by	Felipe
scientific name	Echinoderes guianensis
status	sp. nov.

Treatment

3.3. Echinoderes guianensis View in CoL sp. nov urn:lsid:zoobank.org:act:65E2AD91-5AA4-42D3-A87A-6DE1E56B47DB .

( Figs. 9–13 View Fig View Fig View Fig View Fig View Fig , Tables 3 and 4)

3.3.1. Material examined

Holotype, adult male, collected in November 2017 at the confluence of the Cayenne and Montsin´ery Rivers, French Guiana (western Atlantic Ocean): 04 ◦ 53 ′ 49.2288 ′′ N, 52 ◦ 22 ′ 27.714 ′′ W at the intertidal zone in mud; mounted in Fluoromount G ®, deposited at MNHN under catalogue number: 664 Ma GoogleMaps . Paratype, adult female, same collecting data as holotype; mounted in Fluoromount G ®, deposited at MNHN under catalogue number: 665Ma GoogleMaps . Additional material, one adult male and one adult female, same collecting data as type material; mounted for SEM , stored at IFREMER.

3.3.2. Diagnosis

Echinoderes with short, poorly sclerotized, weakly articulated spines in middorsal position on segment 4, lateroventral position on segment 6 and sublateral position on segment 7, and tubes in lateroventral position on segment 5 and laterodorsal position on segment 10. Enlarged, oval sieve plate in sublateral position on segment 9, consisting of an anterior, slightly convex region with numerous pores and a posterior, slightly concave area with a single, central pore.

3.3.3. Etymology

The specific epithet designates Guiana, the geographical region where the species was found.

3.3.4. Description

See Table 3 for measurements of selected morphological features and body dimensions, and Table 4 for summary of spine, tube, nephridiopore, glandular cell outlet and sensory spot locations.

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 sheath and a triangular, hooked, distally pointed end-piece; basal sheath with a median ridge bearing two short fringes, one basal and another located prior to the junction. Outer oral styles basally joined by triangular, cuticular thickenings. Outer oral styles located anterior to each introvert sector, except in the middorsal sector 6 where a style is missing ( Fig. 9 View Fig ; 12 View Fig A-B).

Introvert with seven concentric rings of spinoscalids (one ring of primary spinoscalids and six rings or regular-sized spinoscalids) and 10 longitudinal sectors defined by the arrangement of the primary spinoscalids ( Fig. 9 View Fig ). Ring 01 with 10 primary spinoscalids, larger than remaining ones, composed of a basal sheath and a distal, elongated, flexible end-piece ( Fig. 9 View Fig ; 12 View Fig C-E). Basal sheath of primary spinoscalids with three overlapping fringes: proximal fringe with three flat projections (trident-like), middle fringe with 7–9 projections becoming shorter towards laterals, distal fringe with 10–12 flat, small, quite inconspicuous projections covering the junction with the end-piece ( Fig. 12E View Fig ). Ring 02 with 10 spinoscalids, arranged as one medially in each sector ( Fig. 9 View Fig ; 12 View Fig C-D). Spinoscalids on this and following rings also composed of a basal sheath and a distal end-piece, smaller than the primary spinoscalids; basal sheath with a proximal, median ridge distally fringed and a distal fringe with 20–25 small projections becoming shorter towards laterals and covering the junction with the end-piece ( Fig. 12F View Fig ). Ring 03 with 20 spinoscalids, arranged as two in each sector. Ring 04 with 10 spinoscalids, arranged as one medially in each sector. Ring 05 with 20 spinoscalids, arranged as two in each sector. Ring 06 with seven spinoscalids, arranged as one medially in each sector except in the sectors 2, 6 and 10. Ring 07 with at least 21 smaller spinoscalids (those of sector 6 not observed) arranged as three in sectors 1, 3 and 9 and two in sectors 2, 4, 5, 7, 8 and 10. Scalid arrangement identical in all sectors from rings 02–05, with one unpaired spinoscalid in ring 02 followed by a quincunx in rings 03–05; in sectors 1, 3 and 9, ring 06 with an unpaired spinoscalid followed by three smaller scalids in ring 07; in sectors 2 and 10, ring 06 without spinoscalids followed by two smaller spinoscalids in ring 07 leaving space for the corresponding trichoscalid and its plate; in sectors 4, 5, 7 and 8, ring 06 with an unpaired spinoscalids followed by two smaller spinoscalids in ring 07 leaving space for the corresponding trichoscalid and its plate ( Fig. 9 View Fig ; 12 View Fig C-D).

Neck with 16 trapezoidal placids, wider at the base, closely adjacent each other, with distinct joint between the neck and first trunk segment. Midventral placid widest (ca. 22 μm at base), remaining ones slightly narrower (ca. 13–15 μm at base). A ring of six short, superficially haired trichoscalids associated with the placids, attached to mushroom-shaped trichoscalid plates in sectors 2, 4, 5, 7, 8 and 10 ( Fig. 9 View Fig ; 10 View Fig A-B; 11A-B; 121, D, G).

Trunk fusiform, heart-shaped in cross-section, composed of 11 segments. Segments 1–2 closed, ring-like cuticular plates; remaining ones with one tergal and two sternal cuticular plates; tergosternal junction of segment 3 quite inconspicuous with LM ( Fig. 10A–D View Fig ; 11B View Fig ; 12A View Fig ). Maximum sternal width at segment 8, relatively narrow compared to total trunk length (MSW8/TL ratio = 17.2%). Cuticular hairs acicular, non-bracteate, emerging from rounded to slightly oval perforation sites. Cuticular hairs arranged in transversal rows (number of rows increasing towards segment 10) that become wavy at subdorsal and ventrolateral to ventromedial regions, interrupted by large, oval, muscular scars in laterodorsal position where hairs are missing throughout segments 2–10; anterior third of segment 1 without hairs ( Fig. 10A–D View Fig ; 11 View Fig A-H; 12A; 13A- I). Posterior segment margins straight, with short, finely serrated primary pectinate fringes; tips of primary pectinate fringes conspicuously shorter on segments 4–10 ( Fig. 10A–D View Fig ; 13 View Fig A-B, D-E, G-H). Secondary pectinate fringes not detected.

Segment 1 with type 1 glandular cell outlet in middorsal and lateroventral positions ( Fig. 10A and B View Fig ; 11A View Fig ). Rounded sensory spots in subdorsal, laterodorsal and ventromedial positions, the former two near the anterior segment margin, the latter near the posterior segment edge; these sensory spots have 5–6 concentric rings of short micropapillae surrounding one or two central pores ( Fig. 10A and B View Fig ; 11 View Fig A-B; 13A).

Segment 2 with one pair of droplet-shaped sensory spots in middorsal and ventromedial positions, and two pairs in laterodorsal position ( Fig. 10A and B View Fig ; 11 View Fig A-B; 13A); on this and following segments, these sensory spots have with numerous, concentric rings of micropapillae surrounding one or two central pores; micropapillae not increasing in length towards the posterior area of the sensory spot ( Fig. 13E–I View Fig ).

Segment 3 with droplet-shaped sensory spots in subdorsal and midlateral positions ( Fig. 10B View Fig ; 11C View Fig ; 13B View Fig ).

Segment 4 with spine in middorsal position ( Fig. 10B View Fig ; 11C View Fig ); spines on this and following segments are acicular, short, poorly sclerotized, weakly articulated, distally frayed (as in Fig. 13D and E View Fig ). Type 1 glandular cell outlets in subdorsal and ventromedial positions ( Fig. 10A and B View Fig ; 11B View Fig ).

Segment 5 with tubes in lateroventral position ( Fig. 10A View Fig ; 11D View Fig ; 13B–C View Fig ). Type 1 glandular cell outlets in subdorsal and ventromedial positions ( Fig. 10A and B View Fig ; 11D View Fig ). Droplet-shaped sensory spots in subdorsal, midlateral and ventromedial positions ( Fig. 10A and B View Fig ; 11D View Fig ; 13B, G View Fig ).

Segment 6 with spines in lateroventral position ( Fig. 10A View Fig ; 11G View Fig ; 13B, D View Fig ). Type 1 glandular cell outlets in subdorsal and ventromedial positions ( Fig. 10A and B View Fig ; 11G View Fig ). Droplet-shaped sensory spots in subdorsal, midlateral and ventromedial positions ( Fig. 10A and B View Fig ; 11G View Fig ; 13B, G View Fig ).

Segment 7 with spines in sublateral position ( Fig. 10A View Fig ; 11H View Fig ; 13E View Fig ). Type 1 glandular cell outlets in subdorsal and ventromedial positions ( Fig. 10A and B View Fig ). Droplet-shaped sensory spots in subdorsal, midlateral and ventrolateral positions ( Fig. 10A and B View Fig ; 11H View Fig ; 13E, H View Fig ).

Segment 8 with type 1 glandular cell outlets in subdorsal and ventromedial positions ( Fig. 10A and B View Fig ). Droplet-shaped sensory spots in subdorsal position ( Fig. 10B View Fig ).

Segment 9 with type 1 glandular cell outlets in subdorsal and ventromedial positions ( Fig. 10A and B View Fig ). One pair of droplet-shaped sensory spots in midlateral and ventrolateral positions, and two pairs in subdorsal position, mesial ones larger and located more posterior than the lateral ones ( Fig. 10A and B View Fig ; 11 View Fig E-F; 13F, I). Nephridiopores in sublateral position at the posterior half of the cuticular plate as oval, enlarged sieve plate openings with an anterior, elongated, slightly convex area with numerous pores and a posterior, slightly concave region with a single, central pore ( Fig. 10A View Fig ; 11E View Fig ; 13I View Fig ).

Segment 10 with short tubes in laterodorsal position ( Fig. 10B, D View Fig ). Type 1 glandular cell outlets in ventromedial position ( Fig. 10A, C View Fig ). Rounded sensory spots in subdorsal and ventrolateral positions ( Fig. 10A–D View Fig ).

Segment 11 with very short lateral terminal spines (LTS:TL average ratio = 7.6%), distally pointed, with hollow central cavity, covered by hairs throughout the first two thirds ( Fig. 10A–D View Fig ; 12A, H–I View Fig ). Males with three pairs of penile spines that emerge from laterodorsal position in the intersegmental joint with the preceding segment; penile spines tube-like, abruptly tapering near the distal tips ( Fig. 10B View Fig ; 12I View Fig ). Females with short lateral terminal accessory spines, covered by hairs, distally pointed ( Fig. 10C and D View Fig ; 12H View Fig ). Tergal extensions short, triangular, softly rounded at the tips ( Fig. 10A–D View Fig ; 12H–I View Fig ).

3.3.5. Remarks

One of the examined specimens for SEM had two types of epibionts: unicellular bacteria near the muscular scars of anterior segments and filamentous bacteria of different lengths attached to the segment 11 edge ( Fig. 12I View Fig ).