Gruvelialepas leguillouxi, Geronimo, 2009

Geronimo, Raffaella Di, 2009, A new species of Gruvelialepas Newman, 1980 (Crustacea, Cirripedia) from the northern Atlantic and remarks on living and fossil closely-related genera, Zoosystema 31 (1), pp. 63-70 : 65-66

Gruvelialepas leguillouxi n. sp.

( Figs 1; 2)

TYPE MATERIAL. — North Atlantic Ocean. Armorican margin, 47°30’N, 7°00’W, 1000 m, II.2006, holotype, specimen attached to the deep-sea scleractinian Madrepora oculata (Linnaeus, 1758) (MNHN-Ci3023). ETYMOLOGY. — The species is named after Dr Erwan Le Guilloux who kindly provided the specimen.

DIAGNOSIS. — Capitulum with 15 plates, including two subrostra ( Figs 1; 2). Rostrolatus overlapping carinolatus. Plates thick, sculptured with longitudinal ridges and growth lines. Carina strongly arched. Scutum triangular with apico-basal ridge dividing plate almost unequally. Tergum rhomboidal with flat apico-basal ridge marked by deep, squared groove. Rostrum higher than wide, strongly convex. Rostrolatus strongly curved inwards and inclined towards rostral side.

DESCRIPTION

The description is based on the single available specimen, which is not disarticulated. No juveniles were found in the sub-rostral region.

Capitulum: height 10 mm, thick plates partly covered by cuticle ( Fig. 2). Cuticle partially hiding the ornamentation of plates, mainly in lower whorl, locally breaking, exposing mineralised plates sculptured with marked longitudinal ridges and growth lines. Rostrolatus overlapping carinolatus ( Fig. 2 A-D).

Carina: broad, length about three times width, bending inwards, strongly arched with tectum transversally convex. Apico-basal ridge raised; four strong longitudinal ridges with obtusely angular growth lines each side of median ridge; basal margin obtusely angular.

Scutum: triangular, length almost twice width, apical part slightly inclined towards tergum; moderately convex transversely, with distinct transverse growth lines. Apico-basal ridge nearer to occludent side, dividing plate unequally; three strong longitudinal ridges between apico-basal ridge and raised occludent border, six on tergal side of plate. Occludent margin weakly convex, tergal margin weakly concave.

Tergum ( Fig. 2E): rhomboidal, elongate, weakly curved away from scutum, length about 2.5 times width. Apico-basal ridge narrow apically and slightly enlarging basalwards, consisting of flat and relatively smooth ridge medially marked by a deep squared groove, starting at about one third from the apex. Numerous flat, longitudinal ridges on both sides of the apico-basal ridge. Marked transverse growth lines.

Rostrum ( Fig. 2D): almost equilaterally triangular, higher than wide, with inwardly bent, triangular apex. Strongly convex transversely, lateral margins concave; outer surface with longitudinal ridges. Apico-basal ridge radially diverging downwards from apex in median subtriangular depressed area.

Subrostrum 1 ( Fig.2D): higher than wide, forming isosceles triangle, apex rounded. Cuticle concealing ornamentation of plate.

Subrostrum 2 ( Fig. 2D): elongate, higher than wide, surface convex; smaller than subrostrum 1, touching it on rostral latus side. Ornamentation of plate hidden by cuticle.

Subcarina: equilaterally triangular, strongly convex transversely, curving towards carina; lateral and basal margins concave. Growth lines and longitudinal ridges hidden by cuticle.

Rostrolatus ( Fig. 2D): inequilaterally triangular, wider than high; strongly curved inwards, inclined towards rostral side. Apex rounded, carinal and rostrolateral margins concave; basal margin slightly concave; carinal margin longer than rostral margin. Outer surface with marked transverse growth lines, longitudinal ridges and grooves, radially diverging from apex.

Mediolatus ( Fig. 2D): low, wide, slightly curved, forming scalene triangle. Strong apico-basal ridge extending from apex near scutal margin; tergal margin short, about 0.5 times length of scutal margin. Three marked longitudinal ridges on surface of plate towards tergum; fine growth lines evident.

Carinolatus: triangular, wider than high, weakly curved, with sub-median, apico-basal fold near median side. Three marked ridges on each side of fold; fine growth lines evident. Carinal margin shorter than median lateral margin.

Peduncle: forming inverted triangle, 5 mm high, covered by several imbricating peduncular scales, each protected by cuticle. Upper whorl consisting of approximately 24 scales, decreasing in number downwards. Where cuticle present, plate morphology hidden, scales appearing small, semi-circular, without ornamentation. Where cuticle removed, peduncular scales appearing elongate, with lateral margins strongly indented, outer surface sculptured with growth lines and fine striae.