Achelia gracilis Verrill, 1900

Sabroux, Romain, Hassanin, Alexandre & Corbari, Laure, 2022, Sea spiders (Arthropoda: Pycnogonida) collected during the Madibenthos Expedition from Martinique shallow waters, European Journal of Taxonomy 851 (1), pp. 1-141 : 8-9

Achelia gracilis Verrill, 1900

Achelia (?) gracilis Verrill, 1900: 582 , pl. 70 fig. 10.

Ammothea gracilis – Cole 1904a: 317–323, pl. 21 figs 4–14. — Helfer & Schlottke 1935: 285. Ammothea (Achelia) gracilis – Giltay 1934b: 5.

Achelia gracilis – Marcus 1940: 79. — Hedgpeth 1948: 244. — Stock 1954a: 117; 1975a: 983; 1979: 10; 1986: 416, tab. 1; 1992a: 139 (list). — Bourdillon 1955: 597. — Müller 1992b: 43, fig. 1. — Child 1996a: 526. — Müller & Krapp 2009: 10–11 , 14 (key), 14–17, 137 (list), tab. 1, figs 2–3. — Varela 2012: 2, fig. 1a. — Lucena & Christoffersen 2018a: 104. — Lucena et al. 2019: 3 (list), 20–21, figs 2a–c, 3–4. — Sabroux et al. 2019b: tab. 1, figs 3, 5. — León-Espinosa et al. 2021: tab. 1. — Ramírez-Tello et al. 2022: tab. 1.

Achelia (Pigrolavatus) gracilis – Fry & Hedgpeth 1969: 104, figs 152–153, 155.

Type material

Holotype: YPM IZ 003366.CR (not examined). Type locality: Flatts Inlet , Bermuda.

Material examined

MARTINIQUE • 1 ♂; Grande Anse d’Arlets ; 14°29.9ʹ N, 61°05.4ʹ W; depth 28 m; 7 Sep. 2016; st. AB157; MNHN-IU-2016-849/ MK411162 • 1 ♂; Grande Anse d’Arlets ; 14°30.5ʹ N, 61°06.1ʹ W; depth 20–23 m; 6 Sep. 2016; st. AB152; MNHN-IU-2016-851/ MK411164 • 1 ♂; same collection data as for preceding; MNHN-IU-2016-888/ MK411197 • 1 juv.; Baie de Fort-de-France ; 14°32.6ʹ N, 61°04.7ʹ W; depth 0–1 m; 6 Sep. 2016; st. AM002; MNHN-IU-2016-85/ MK411170 • 1 ♂ ov.; same collection data as for preceding; MNHN-IU-2016-1193 • 1 ♂; Presqu’Île de la Caravelle ; 14°44.1ʹ N, 60°50.8ʹ W; depth 16 m; 18 Sep.2016;st.AB189;MNHN-IU-2016-881/ MK411191 • 1♂; Ste-Marie , 14°46.3ʹ N, 60°57.5ʹ W; depth 20 m; 20 Sep. 2016; st. AB260; MNHN-IU-2016-1062/ MK411040 • 1 juv.; Les Anses-d’Arlet; 14°29.7ʹ N, 61°05.4ʹ W; depth 19 m; 7 Sep. 2016; st. AB155; MNHN-IU-2016-1114/ MK411053 • 1 ♀ gr.; E of Le Vauclin ; 14°34.7ʹ N, 60°45.9ʹ W; depth 22 m; 16 Sep. 2016; st. AB181; MNHN-IU-2016-1180/ MK411073 • 1 ♀ gr.; Le Robert ; 14°41.1ʹ N, 60°51.4ʹ W; depth 10 m; 19 Sep. 2016; st. AB195; MNHN- IU-2016-1182 • 1 ♂; same collection data as for preceding; MNHN-IU-2016-1330/ MK411104 • 2 ♂♂, 1 juv.; same collection data as for preceding; MNHN-IU-2016-1408 • 1 ♀; Trois Rivières ; 14°27.7ʹ N, 60°57.8ʹ W; depth 4–5 m; 25 Sep. 2016; st. AB354; MNHN-IU-2016-1276/ MK411095 • 1 ♀ gr.; same collection data as for preceding; MNHN-IU-2016-1380/ MK411108 • 1 ♂ ov.; Presqu’Île de la Caravelle ; 14°48.4ʹ N, 60°52.8ʹ W; depth 23–25 m; 20 Sep. 2016; st. AB197; MNHN-IU-2016-1379/ MK411107 • 1 juv.; same collection data as for preceding; MNHN-IU-2016-1384 .

Remarks

This species was distinguished from Achelia sawayai Marcus, 1940 based on the key in Müller & Krapp (2009), relying on the number of palp articles (7 in A. gracilis , 8 in A. sawayai ) and the number of dorsolateral tubercles on coxae 1 on the first and second legs of males (4 in A. gracilis , 3 in A. sawayai ). Achelia gracilis was previously recorded from Martinique by Bourdillon (1955) on the hulls of scows in Fort-de-France port. Madibenthos sampling reveals that this species is present on both the Atlantic and Caribbean coasts of Martinique. Achelia gracilis is a common species in the Caribbean, almost as common as its close congener, Achelia sawayai ( Child 1996a) .

DNA barcoding data ( Sabroux et al. 2019b) suggest that this species name hides two potential cryptic species (intracluster p-distance = 0–0.010; intercluster p-distance = 0.105 –0.112), here named group 1 (MNHN-IU-2016-849, -851, -857, 881, -888, -1114, -1180, -1276, -1379 and -1380) and group 2 (MNHN-IU-2016-1062 and -1330) ( Table 2 and Appendix).

Distribution

Tropical West Atlantic ( Bermuda, Caribbean and Brazil).

Depth range

0– 18 m. One record at 157 m is regarded as a likely contamination by shallow fouling on the hull of a ship. We extend this depth-range to 28 m.