Echinoderes guianensis Cepeda & Gayet & Spedicato & Michaud & Zeppilli 2022, sp. nov
Creators: name: Cepeda, Diego
name: Gayet, Nicolas
name: Spedicato, Adriana
name: Michaud, Emma
name: Zeppilli, Daniela
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Kinorhyncha
Cyclorhagida
Echinorhagata
Echinoderidae
Echinoderes
Echinoderes guianensis

description: 3.3. Echinoderes guianensis sp. novurn:lsid:zoobank.org:act: 65E2AD91-5AA4-42D3-A87A- 6DE1E56B47DB.
(Figs. 9–13, 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. Paratype, adult female, same collecting data as holotype; mounted in Fluoromount G ®, deposited at MNHN under catalogue number: 665Ma. 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; 12 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). Ring 01 with 10 primary spinoscalids, larger than remaining ones, composed of a basal sheath and a distal, elongated, flexible end-piece (Fig. 9; 12 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). Ring 02 with 10 spinoscalids, arranged as one medially in each sector (Fig. 9; 12 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). 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; 12 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; 10 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; 11B; 12A). 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; 11 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; 13 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; 11A). 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; 11 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; 11 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).
Segment 3 with droplet-shaped sensory spots in subdorsal and midlateral positions (Fig. 10B; 11C; 13B).
Segment 4 with spine in middorsal position (Fig. 10B; 11C); spines on this and following segments are acicular, short, poorly sclerotized, weakly articulated, distally frayed (as in Fig. 13D and E). Type 1 glandular cell outlets in subdorsal and ventromedial positions (Fig. 10A and B; 11B).
Segment 5 with tubes in lateroventral position (Fig. 10A; 11D; 13B–C). Type 1 glandular cell outlets in subdorsal and ventromedial positions (Fig. 10A and B; 11D). Droplet-shaped sensory spots in subdorsal, midlateral and ventromedial positions (Fig. 10A and B; 11D; 13B, G).
Segment 6 with spines in lateroventral position (Fig. 10A; 11G; 13B, D). Type 1 glandular cell outlets in subdorsal and ventromedial positions (Fig. 10A and B; 11G). Droplet-shaped sensory spots in subdorsal, midlateral and ventromedial positions (Fig. 10A and B; 11G; 13B, G).
Segment 7 with spines in sublateral position (Fig. 10A; 11H; 13E). Type 1 glandular cell outlets in subdorsal and ventromedial positions (Fig. 10A and B). Droplet-shaped sensory spots in subdorsal, midlateral and ventrolateral positions (Fig. 10A and B; 11H; 13E, H).
Segment 8 with type 1 glandular cell outlets in subdorsal and ventromedial positions (Fig. 10A and B). Droplet-shaped sensory spots in subdorsal position (Fig. 10B).
Segment 9 with type 1 glandular cell outlets in subdorsal and ventromedial positions (Fig. 10A and B). 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; 11 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; 11E; 13I).
Segment 10 with short tubes in laterodorsal position (Fig. 10B, D). Type 1 glandular cell outlets in ventromedial position (Fig. 10A, C). Rounded sensory spots in subdorsal and ventrolateral positions (Fig. 10A–D).
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; 12A, H–I). 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; 12I). Females with short lateral terminal accessory spines, covered by hairs, distally pointed (Fig. 10C and D; 12H). Tergal extensions short, triangular, softly rounded at the tips (Fig. 10A–D; 12H–I).
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).
description: Published as part of 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), pp. 179-195 in Zoologischer Anzeiger 301 on pages 186-189, DOI: 10.1016/j.jcz.2022.10.008, http://zenodo.org/record/10375291