Anoplodactylus micros Bourdillon, 1955

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 : 93-96

Anoplodactylus micros Bourdillon, 1955

Figs 20 , 24

Anoplodactylus micros Bourdillon, 1955: 591–592 , pl. 1 fig. 3–8.

Anoplodactylus micros – Stock 1986: tab. 1. — Montoya Bravo et al. 2009: 22–24. — Müller & Krapp 2009: 10, 86 (key), 103–105, 137 (list), tab. 1, fig. 55. — Lucena et al. 2015: tab. 1. — Sabroux et al. 2019b (pro parte): tab. 1, figs 3, 5.

Material examined

Neotype MARTINIQUE • ♂; Les Anses-d’Arlet; 14°29.7ʹ N, 61°05.4ʹ W; depth 19 m; 7 Sep. 2016; st. AB155; MNHN-IU-2016-1325/ MK411100 .

Other material

MARTINIQUE • 1 ♀, 3 juvs; same collection data as for neotype; MNHN-IU-2016-1230 • 1 ♀; same collection data as for neotype; MNHN-IU-2016-1387/ MK411110 • 1 ♀; same collection data as for neotype; MNHN-IU-2016-1388 • 1 ♂; Anse Noire ; 14°32ʹ N, 61°05.3ʹ W; depth 13 m; 6 Sep. 2016; st. AB150; MNHN-IU-2016-802/ MK411125 • 1 ♂; Grande Anse d’Arlets ; 14°30.5ʹ N, 61°06.1ʹ W; depth 20–23 m; 6 Sep. 2016; st. AB152; MNHN-IU-2016-803 • 1 preadult ♀; Pointe du Vauclin ; 14°33.6ʹ N, 60°49.7ʹ W; depth 2 m; 12 Sep. 2016; st. AD230; MNHN-IU-2016-804/ MK411126 • 1 ♂; same collection data as for preceding; MNHN-IU-2016-568 • 1 ♀; Grande Anse d’Arlets ; 14°29.9ʹ N, 61°05.4ʹ W; depth 28 m; 7 Sep. 2016; st. AB157; MNHN-IU-2016-536 • 1 ♂, 1 ♂ ov.; Baie de St-Pierre ; 14°45.1ʹ N, 61°11ʹ W; depth 17 m; 4 Oct. 2016; st. AB388; MNHN-IU-2016-1059 • 1 ♂; same collection data as for preceding; MNHN-IU-2016-1386 • 1 ♂; Grande Anse du Diamant ; 14°28ʹ N, 61°00.1ʹ W; depth 12 m; 26 Sep. 2016; st. AB360; MNHN-IU-2016-1080 • 1 ♂; same collection data as for preceding; MNHN-IU-2016-1218 • 1 ♂; Le Prêcheur ; 14°49.1ʹ N, 61°13.8ʹ W; depth 20–25 m; 8 Oct. 2016; st. AS 576; MNHN-IU-2016-1087 • 1 ♂, 1 ♀; Presqu’Île de la Caravelle ; 14°48.4ʹ N, 60°52.8ʹ W; depth 23–25 m; 20 Sep. 2016; st. AB197; MNHN-IU-2016-1139 • 1 ♂; same collection data as for preceding; MNHN-IU-2016-1250 • 1 preadult ♂; same collection data as for preceding; MNHN-IU-2016-1391 • 1 ♀; Grande Anse du Diamant ; 14°27.9ʹ N, 61°01.4ʹ W; depth 17 m; 26 Sep. 2016; st. AB358; MNHN- IU-2016-1211 • 1 ♀, 1 juv.; Anse des Galets ; 14°51.4ʹ N, 61°12.8ʹ W; depth 10 m; 7 Oct. 2016; st. AB567; MNHN-IU-2016-1246 • 2 ♀♀, 4 ♀♀ gr.; Pointe de la Baleine ; 14°31.1ʹ N, 61°05.9ʹ W; depth 17–19 m; 30 Sep. 2016; st. AB369; MNHN-IU-2016-1258 • 1 ♀; Anse Couleuvre ; 14°50.4ʹ N, 61°13.4ʹ W; depth 7 m; 1 Oct. 2016; st. AB463; MNHN-IU-2019-3390 .

Description (neotype, ♂, MNHN-IU-2016-1325)

BODY.Small-sized species; trunk segmentation incomplete with 3 rd and 4 th segments fused; cuticle smooth. No dorsomedian ornamentation. Ocular tubercle less than twice as tall as wide, distal tip triangular, with two pointy lateral sense organs above four large pigmented eyeseyes. Two setae laterally positioned on ocular tubercle between anterior and posterior eyes. Post-ocular neck medium-sized. Lateral processes about as long as wide, well separated by less than their own diameter, 3 rd and 4 th the closest. Lateral processes ornamented with a rounded tubercle, bearing one seta.

PROBOScIS. Cylindrical, with setae on ventral surface, constricted medially and distally.

ABDOMEN. Medium-sized, diagonally oriented, reaching beyond lateral processes of 4 th trunk segment.

CHELIFORE. 2-articled, reaching beyond mouth. Scape 1-articled, about 4 times as long as wide, carrying setae distally. Chela carrying setae, fingers slightly longer than palm. Fingers subequal, crossing at tip, with few teeth.

PALP. Absent.

OvIGER. 6-articled, with scarce setae. 1 st article about 1.5 times as long as wide. 2 nd article about ¼ longer than 1 st article, slenderer. 3 rd article longest, 1.5 times as long as 1 st, with constriction at base. 4 th and 5 th articles about half as long as 3 rd, 5 th most setose. 6 th article smallest, bud-like, with distal seta.

LEGS. Stout. Coxa 1 slightly longer than wide, carrying setae at distal margin. Coxa 2 about ⅔ longer than coxa 1 or 3, with small ventrodistal spur on 3 rd and 4 th legs. Femur longest, more than 3 times as long as median width, with one long dorsal seta on distal margin, and one short cement gland tube, about mid-sized and slightly constricted at base. Tibia 1 about ¾ of femur length, with one long seta near distal margin. Tibia 2 about ⅔ of femur size, with one long seta on distal half rising from low tubercle. Tarsus short, trapezoid, with one ventrodistal spine. Propodus about 0.9 times as long as tibia 2, sole straight, with strong heel carrying 2 large heel spines followed by 2 smaller spines; sole carrying 2 small spines on proximal 3 rd directed distally. Lamina on distal part of sole, about ⅔ of sole length. Main claw almost reaching heel, straight with terminal bending. Auxiliary claws present, very small.

MEASUREMENTS (mm). Trunk 0.44; abdomen 0.18; proboscis 0.25; chelifore 0.26; coxa 1 0.10; coxa 2 0.17; coxa 3 0.13; femur 0.41; tibia 1 0.32; tibia 2 0.3; tarsus 0.05; propodus 0.22; main claw 0.13.

Sexual dimorphism

Females with dilated femorae, no oviger.

Individual variability

Number of propodus heel spines variable, with 2 or 3 large spines and 2 or 3 smaller spines. Sole spines also variable in number, 1 or 2.

Remarks

Because the holotype is considered to be lost ( Müller & Krapp 2009 and MNHN collections data), we propose the selection of a new specimen from type locality ( Martinique, southern Caribbean coast) to designate as a neotype.

According to Müller & Krapp (2009), the two similar species Anoplodactylus micros and A. bahamensis can be distinguished based on the setae on the ventral side of the proboscis in A. bahamensis . However, both species exhibit setae in Madibenthos material. The species differ in two aspects: (i) the most obvious is the size of the specimens, the trunk of A. micros in the present material and in the original description being about half as long as A. bahamensis as measured by Child (1977b); (ii) the cement gland opening is larger in A. bahamensis than in A. micros , although in some specimens this distinction may be tricky ( Fig. 20 ). Regarding molecular data, the two species are clearly distinct (interspecific p-distance = 0.077– 0.1). Interestingly, within the material identified as A. micros the presence of two clusters (Sabroux et al. 2019) with p-distances similar to that between A. micros and A. bahamensis (intercluster p-distance = 0.077 –0.079) suggests that there may be at least two cryptic species. We thus informally describe two groups: group 1 includes the neotype, MNHN-IU-2016-1325, and specimens MNHN-IU-2016-802 and MNHN-IU-2016-1387, and group 2 is only represented by MNHN-IU-2016-804 (see Appendix for complete list).

The species Anoplodactylus micros was originally collected in Petite Anse du Diamant on the southern Caribbean coast ( Bourdillon 1955). Here, the species was mostly found on the Caribbean coast, except six specimens sampled at Pointe du Vauclin and Presqu’Île de la Caravelle.

Distribution

So far only recorded from the Colombian Caribbean and Martinique.

Depth range

2– 30 m.

Figures

Fig. 20. Cement gland pores of Anoplodactylus micros Bourdillon, 1955 and A. bahamensis Child, 1997.

Fig. 24. Anoplodactylus micros Bourdillon, 1955, neotype, ♂, MNHN-IU-2016-1325. A. Body, dorsal view. B. Body, lateral view (same scale as A). C. Proboscis in ventral view (same scale as A). D. Ocular tubercle, frontal view. E. Oviger. F. Second leg. G. Cement gland opening of second leg. H. Coxa 2 of third leg. I. Tarsus and propodus of second leg. J. Chelifore.