Anoplodactylus madibenthos, Sabroux & Hassanin & Corbari, 2022

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 : 88-91

Anoplodactylus madibenthos sp. nov.

urn:lsid:zoobank.org:act:0E6D16F7-B75F-4BF7-B30C-934203E22322

Figs 22A–J , 23

Anoplodactylus sp. 1 . – Sabroux et al. 2019b: 1531, tab. 1, fig. 3.

Material examined

Holotype MARTINIQUE • ♂; Baie du Robert; 14°42ʹ N, 60°53.8ʹ W; depth 2 m; 24 Sep. 2016; st. AB452; MNHN- IU-2016-1071/ MK411043 .

Paratypes MARTINIQUE • 1 ♀; Les Anses-d’Arlet; 14°29.6ʹ N, 61°05.5ʹ W; depth 8–12 m; 7 Sep. 2016; st. AR103; MNHN-IU-2016-807/ MK411129 • 1 ♀; Pointe Michel; 14°26.4ʹ N, 60°49.3ʹ W; depth 2 m; 12 Sep. 2016; st. AB120; MNHN-IU-2016-537 • 1 juv.; Case-Pilote; 14°38.9ʹ N, 61°09.1ʹ W; depth 0–14 m; 27 Sep. 2016; st. AS 365; MNHN-IU-2016-1078 • 1 ♀; Trois Rivières; 14°27.8ʹ N, 60°57.9ʹ W; depth 3–4 m; 25 Sep. 2016; st. AB356; MNHN-IU-2016-1202/ MK411079 • 1 ♂ ov., 1 ♀; Grande Anse du Diamant; 14°28ʹ N, 61°00.1ʹ W; depth 12 m; 26 Sep. 2016; st. AB360; MNHN-IU-2016-1235 • 1 ♂; same collection data as for preceding; MNHN-IU-2019-3401 • 1 juv.; Baie du Robert; 14°42ʹ N, 60°53.8ʹ W; depth 1–3 m; 24 Sep. 2016; st. AR453; MNHN-IU-2016-1321 • 1 ♂, 1 ♀, 4 juvs; Ste-Luce; 14°27.3ʹ N, 60°55.5ʹ W; depth 15 m; 10 Sep. 2016; st. AB062; MNHN-IU-2016-1453.

Etymology

Apposition. Named after the Madibenthos Expedition.

Description (holotype, ♂, MNHN-IU-2016-1071)

BODY. Small-sized species, slender, cuticle granular. Trunk incompletely segmented with segments 3 and 4 fused. No dorsal ornamentation. Post-ocular neck short. Ocular tubercle about twice as tall as wide, with rounded tip and four pigmented eyes. 1 st and 2 nd lateral processes about 1.5 times as long as wide, 3 rd and 4 th articles about as long as wide, all well separated by about their own diameter, without ornamentation.

PROBOScIS. Elongated and cylindrical, widening at mid-length; proboscis tip not reaching further than chelifore scape.

ABDOMEN. Long, tapering distally, oriented diagonally. No basal articulation.

CHELIFORE. 2-articled, fingers reaching not far beyond mouth. Scape 1-articled, slender, about 5 times as long as wide. Chela small, palm and fingers of about same size. Fingers curved, subequal, with few teeth: four teeth on movable finger, six on immovable finger.

PALP. Absent.

OvIGER. 6-articled. 1 st article about as long as wide. 2 nd article about 3 times as long as wide, carrying scarce setae. 3 rd article longest, gently curved, about 1.5 times as long as 2 nd and 10 times as long as wide, with scarce setae. 4 th article gently curved, about 3 times as long as wide, with setae on outer surface. 5 th article about ⅔ length of 4 th, less than 3 times as long as wide, with scarce setae on inner and outer surfaces. 6 th article shortest, about ⅔ length of 5 th and twice as long as wide, carrying setae on inner surface.

LEGS. Slender. Coxae 1 and 3 subequal, slightly longer than wide, coxa 1 carrying dorsodistal setae. Coxa 2 about 3 times as long as basal width, slightly shorter than coxae 1 and 3 together; small spur present on ventral surface near distal margin carrying gonopore on 3 rd and 4 th legs. Coxa 3 carrying ventral setae. Femur, tibia 1, tibia 2 and propodus longer on 1 st and 2 nd legs than on 3 rd and 4 th legs. Femur widening distally, about 5 times (1 st leg) and 4 times (3 rd leg) as long as distal width, carrying scarce setae; one dorsal spur on distal margin carrying one long seta. Cement gland pore carried on femur as low, straight and elongated aperture. Tibia 1 curved, about 10 times (1 st leg) and 7 times (3 rd leg) as long as basal width and subequal to femur, carrying many setae along and one long dorsal seta at distal margin. Tibia 2 10 times (1 st leg) and 8 times (3 rd leg) as long as wide and subequal to femur and tibia 1, with several setae along and one long dorsal seta on distal fourth. Tarsus short, about as long as wide, carrying setae and one ventral spine on distal margin. Propodus about 0.6 times as long as tibia 2 and about 4 times as long as wide, straight, with setae and one long seta distally; heel carrying 2 heel spines, the distal larger and pectinated; sole carrying 12 short spines and very short lamina distally. Main claw reaching heel spines, slightly curved, slenderer and longer on 1 st and 2 nd legs than on 3 rd and 4 th legs. No auxiliary claw.

MEASUREMENTS (mm). Trunk 1.06; abdomen 0.40; proboscis 0.57; chelifore 0.55; coxa 1 0.23; coxa 2 0.45; coxa 3 0.28; femur 1.23 (1 st leg), 1.04 (3 rd leg); tibia 1 1.12 (1 st leg), 0.93 (3 rd leg); tibia 2 1.08 (1 st leg), 0.93 (3 rd leg); tarsus 0.17 (1 st leg), 0.15 (3 rd leg); propodus 0.67 (1 st leg), 0.57 (3 rd leg); main claw 0.56 (1 st leg), 0.42 (3 rd leg).

Sexual dimorphism

Females larger, without oviger, femur moderately inflated, without cement gland. All four pairs of coxa 2 carrying gonopore on ventral surface, at the tip of a low distal bulge ( Fig. 23 ).

Remarks

The propodal pectinated spine is observed in five species: Anoplodactylus madibenthos sp. nov., A. exageratus Stock, 1994 from Indonesia, A. perissoporus Arango & Krapp, 2007 from Australia, A. tenuicorpus Child, 1991 from the Indoacific and A. pectinus Hedgpeth, 1948 , which is included in the present report. The three former species, which belong to the same tenuicorpus complex, differ a lot from A. madibenthos by their extreme slenderness and the ovigers which articulate with the first pair of lateral processes.

The species Anoplodactylus pectinus ( Fig. 22K–L ) is morphologicaly the closest relative to A. madibenthos sp. nov. Anoplodactylus pectinus was sampled in Martinique, and we also consulted the holotype of Hedgpeth (1948). The distance between the lateral processes is larger in A. pectinus (peculiarly between segments 2 and 3), and the proboscis is distally widened in A. pectinus , whereas it is cylindrical in A. madibenthos . The CO1 analysis also supported a deep divergence between the two species (intraspecific p-distance = 0–0.1, interspecific p-distance = 0.174 –0.180) ( Sabroux et al. 2019b; see Appendix).

Specimens were collected on both the Atlantic and Caribbean coasts.

Distribution

Only known from Martinique.

Depth range

2– 15 m.

Figures

Fig. 22. Comparison of Anoplodactylus madibenthos sp. nov. (A–J) and A. pectinus Hedgpeth, 1948 (K–L). A–J. Holotype, ♂, MNHN-IU-2016-1071. K–L. MNHN-IU-2016-1254. A. Body, dorsal view. B. Proboscis in ventral view. C. Body lateral view (same scale as A). D. Oviger. E. Chela. F. Third leg. G. Tarsus and propodus of third leg. H. Cement gland opening. I. First leg. J. Tarsus and propodus of first leg. K. Body, dorsal view. L. Proboscis in ventral view (same scale a A).

Fig. 23. Anoplodactylus madibenthos sp. nov., paratype, ♀, MNHN-IU-2016-1202. A. First leg. B. Third leg.