Nymphon dorlis, 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 : 56-59

Nymphon dorlis sp. nov.

urn:lsid:zoobank.org:act:8B1908A6-04E4-4B2E-B142-8E6E9F0990AD

Fig. 11

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

Material examined

Holotype MARTINIQUE • ♂; Presqu’Île de la Caravelle; 14°44.1ʹ N, 60°50.8ʹ W; depth 16 m; 18 Sep. 2016; st. AB189; MNHN-IU-2016-879/ MK411189 .

Paratypes MARTINIQUE • 1 ♂; same collection data as for holotype; MNHN-IU-2016-870/ MK411181 • 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-2016-1298 • 1 ♂; Le François; 14°38.5ʹ N, 60°46.3ʹ W; depth 63 m; 15 Sep. 2016; st. AD234; MNHN-IU-2016-1313 • 1 juv.; Pointe de la Baleine; 14°31.1ʹ N, 61°05.9ʹ W; depth 24 m; 30 Sep. 2016; st. AR413; MNHN-IU-2016-1221.

Etymology

Noun in apposition. Named after the Dorlis, also called ‘night husband’, a malevolent, invisible character of Martinique folklore. It fits somehow with the aspect of this species, with horn-like lateral sense organs on the ocular tubercle and large setose chelae; and only males were found.

Description (holotype, ♂, MNHN-IU-2016-879)

BODY. Species rather small and stout, trunk completely segmented, cuticle smooth. No dorsomedian tubercle. Ocular tubercle rounded, as tall as wide, positioned anteriorly to 1 st lateral processes, with 2 conspicuous pointy lateral sense organs beside tip and four pigmented eyes. Preocular neck short, shorter than wide. Oviger base jointing 1 st lateral process. Lateral processes without ornamentation, well separated by less than their own diameter.

PROBOScIS. Rounded and large, reaching distal margin of chelifore scape in lateral view.

ABDOMEN. Medium-sized, not reaching beyond lateral processes, carrying several setae at about midlength, directed diagonaly. No basal segmentation.

CHELIFORE. 2-articled, reaching far beyond proboscis. Scape 1-articled, 4.5 times as long as wide, carrying setae. Chela very large, palm longer than fingers ornamented with setae. Fingers sub-equal in length, bearing simple and bifurcated teeth, 10 bifurcated and 3 simple teeth on both fingers.

PALP. 5-articled. 1 st article shortest, shorter than wide. 2 nd article longest, about 7 times as long as wide, with distal setae. 3 rd article about 0.8 times as long as 2 nd, carrying ventrodistal setae. 4 th article about 0.6 times as long as 5 th, about 3 times as long as wide, with many long ventral setae along its length. 5 th article 0.8 times as long as 3 rd, carrying many ventral setae.

OvIGER. 10-articled. 1 st article shorter than wide. 2 nd article about 1.5 times as long as wide. 3 rd article about twice as long as wide. 4 th article about 4 times as long as wide, with a few distal setae. 5 th article longest, about twice as long as 4 th, straight, strongly swollen distally, with light constriction at base. 6 th article about ⅔ as long as 4 th, with many setae along its length. 7 th and 10 th articles subequal, about ¾ of 6 th article length. Strigilis formula 12:10:9:10. Strigilis spines compound, carrying many lateral teeth, proximalmost shortest and spatulated to oblong, median spines lancelolate, distalmost spines spatulated to oblong, longer than proximalmost. Intermediary position spines roughly intermediary in shape. Distalmost spines of 9 th and 10 th articles longest among strigilis articles. Terminal claw about ⅔ length of 10 th article.

LEGS. Slender, setose. Coxa 1 no longer than broad. Coxa 2 about 3 times as long as maximal width, longer than coxae 1 and 3 together. Coxa 3 about as long as wide. Femur about 8 times as long as wide and more than twice as long as coxa 2, ventrally carrying one row of hardly conspicuous cement glands and cement gland pores, 44 glands counted on 3 rd leg. No cement gland tube. Tibia 1 gently curved, slender, about as long as femur. Tibia 2 even slenderer, longest, about 1.5 times length of femur or tibia 1, with many tall setae along and two ventral spines on distal margin. Tarsus medium-sized, trapezoid, one spine distally on ventral surface. Propodus straight, slender, about 3 times as long as tarsus, and ¼ of tibia 2 length. Main claw short, about ¼ of propodal length, well curved. Auxiliary claws present, well curved, as long as main claw. Both main claw and auxiliary claws with small teeth on inner surface.

MEASUREMENTS (mm). Trunk 1.13; abdomen 0.22; proboscis 0.61; chelifore scape 0.61; chela palm 0.56; chela fingers 0.29; coxa 1 0.16; coxa 2 0.54; coxa 3 0.20; femur 1.24; tibia 1 1.34; tibia 2 1.82; tarsus 0.15; propodus 0.36; main claw 0.12; auxillary claw 0.12.

Sexual dimorphism

No female available.

Individual variability

Strigilis formula more or less with one compound spine per article in investigated specimens, the highest number of compound spines always on the first strigilis article. Chela teeth number variable, 13–16 on movable finger and 13–20 on immovable finger in investigated specimens.

Remarks

Nymphon dorlis sp. nov. is a new species in the aequidigitatum -group ( Child 1988b). It can be discriminated from most of its relatives by the following three criteria: (i) preocular neck short, (ii) tarsus about ⅓ as long as propodus; (iii) tibiae 2 about 1.5 times as long as femorae or tibiae 1. Additionally, this species can be distinguished from N. biformidens Stock, 1974 from Madagascar by the larger chelifore palms and shorter fingers of N. dorlis , as well as its conspicuous horn-like lateral sense organs ( Stock 1974). It can be distinguished from N. aequidigitatum Flynn, 1919 from Australia by the shorter tarsi (⅓ of propodus length in N. dorlis against ½ in N. aequidigitatum ) and the prominent lateral organs of N. dorlis (see Stock 1973). It differs from N. draconis Child, 1990 from the Indo-Pacific by having no conspicuous range of cement gland tubes on the ventral side of the femorae, a longer main claw relatively to the auxiliary claws, and the tarsus only about ⅓ of propodus length (against about ½ for N. draconis ; Child 1990). Finally, it differs from N. megacheles Child, 1988 by the larger space between the lateral processes, the longer 5 th palp segment, the shorter main claw relatively to the propodus and the slenderer leg articles ( Child 1988a).

Among Martinique species, Nymphon dorlis sp. nov. could be mistaken for N. macabou Müller, 1990 . The two species differ by the propodus, which is straight in N. dorlis and curved in N. macabou ; and the tibiae 2, which are slender and 1.5 times as long as the femorae, while in N. macabou tibiae 2 are only slightly longer than the femorae ( Müller 1990a).

The species was only collected on the Atlantic coast.

Depth range

Only known from type locality. 16– 63 m.

Figures

Fig. 11. Nymphon dorlis sp. nov., holotype, ♂, MNHN-IU-2016-879. A. Body, dorsal view. B. Body, lateral view (same scale as A). C. Palp. D. Oviger. E. Pointed teeth of oviger. F. Chela. G. Third leg. H. Tarsus and propodus of third leg.