Coralaxius nodulosus ( Meinert, 1877 )

Ngoc-Ho, Nguyen, 2003, European and Mediterranean Thalassinidea (Crustacea, Decapoda), Zoosystema 25 (3), pp. 439-555 : 454-457

Coralaxius nodulosus ( Meinert, 1877)

Axius nodulosus Meinert, 1877: 212 . — Stephensen 1910: 276, figs 1-5. — de Man 1925b: 18. — Balss 1926: 26. — Poulsen 1941: 208, fig. 2.

Coralaxius abelei Kensley & Gore, 1982: 1278 , figs 1-6.

“? Axiopsis nodulosus ” – ° Borradaile 1903: 539.

Coralaxius nodulosus – S akai & de Saint Laurent 1989: 11. — Kensley 1994: 814, 822. — d’Udekem d’Acoz 1999: 153.

REMARKS

This species was first described as Axius nodulosus by Meinert in 1877 from a single specimen of 9 mm in total length from the North Sea off Nymindegab, and has never been discovered again. Stephensen (1910: figs 1-4) depicted both P1, left P2, P4 of the type as well as the telson and uropods. Poulsen (1941: 209, fig. 2) reviewed and figured it in detail. Poulsen (1941: 213) believed that the specimen was a postlarva or a grown-up thalassinidean, but differed in one or more characters from all known postlarvae and young thalassinideans in the area. Likewise, no similarities are found between this specimen and the larvae referred to Calocarides coronatus (second stage, tl. 10 mm including rostrum), studied later by Elofsson (1959).

Sakai & de Saint Laurent (1989) assigned the species to the genus Coralaxius Kensley & Gore, 1982 . Meinert’s specimen resembles the type species of Coralaxius , C. abelei Kensley & Gore, 1982 (from Florida and the Caribbean) in: 1) the short rostrum; 2) the morphology of both major and minor P1; 3) the morphology of P2; 4) the biunguiculate P4; and 5) the telson and uropods (see Stephensen 1910: figs 1-5 and Poulsen 1941: fig. 2 as compared with Kensley & Gore 1982: figs 1-6 and Kensley 1994: figs 5, 6).

Kensley (1994: 814), describing more materials of Coralaxius , considered further that Meinert’s specimen was “unquestionably a mature male of Coralaxius abelei ” (the species name nodulosus has therefore priority over abelei ), that it “came from the Caribbean and the collection data became confused at some point”. Kensley’s argument seems convincing, and as C. nodulosus has not been collected again in the North Sea or European waters for over a century, it is likely to be an alien to the European fauna.

Genus Levantocaris Galil & Clark, 1993 TYPE SPECIES. — Levantocaris hornungae Galil & Clark, 1993 , by monotypy.

DIAGNOSIS. — Rostral triangular, margin with denticles, short median carina present, lateral carina unarmed. Eye with reduced pigmentation, anteriorly flattened, eyestalk rounded. Antenal acicle as a well developed spike. Mx2 scaphognathite with long posterior seta. Mxp3 with toothed crest on mesial surface of ischium. First pereopod chelate, subequal, P2 chelate, P3-5 simple.

Exopod on Mxp1-3; single epipod on Mxp1-3 and P1-4; single podobranch on Mxp1-3 and P1-3; paired arthrobranch on Mxp3 and P1-4; single pleurobranch on P2-4.

Male Plp1 slightly dilated subdistally, male Plp2 with appendix interna and appendix masculina. Telson longer than wide, bearing dorsal spines; posterior bor- der convex with median spine. Uropodal exopod with transverse suture.

Levantocaris hornungae Galil & Clark, 1993 ( Fig. 4 )

Levantocaris hornungae Galil & Clark, 1993: 48 , figs 1-4. — d’Udekem d’Acoz 1999: 154. — ° Türkay 2001: 289.

Axiella or Axiidae n. sp. – Noël 1992: 80, nomen nudum.

TYPE MATERIAL. — Holotype:, 50 km NW of Haifa, Israel ( NHML 1992 : 608).

MATERIAL EXAMINED. — Israel. 50 km NW of Haifa, 33°00’N, 34°35’E, 1400 m, B. Galil coll., 17.XII.1991, 1, holotype, cl. 11 mm, tl. 25.3 mm including rostrum (figured) ( NHML 1992: 608).

DISTRIBUTION. — Mediterranean: Israel ( Galil & Clark 1993), Catalan coast (de Saint Laurent pers. comm.), in deep waters: 1400 m ( Galil & Clark 1993).

DIAGNOSIS (partly after Galil & Clark 1993) Rostrum ( Fig. 4B ) elongate, triangular, dorsal surface concave, lateral margin with two or three denticles, continuous posteriorly to unarmed lateral carina. Eyestalk less than half rostrum length, cornea unpigmented. Gastric region slightly convex, carrying short, unarmed median carina, cervical groove well defined. Abdominal somites ( Fig. 4A ) unarmed, pleura ventrally rounded, pleuron 2 largest. Telson ( Fig. 4G ) over 1.6 times as long as proximal width, proximal half with two pairs of dorsal spines; three to five spinules on lateral border, posterior border convex with median spine.

A2 acicle ( Fig. 4B ) reaching approximately middle of fourth article of A2 peduncle. Md, Mx1, Mx2 (see Galil & Clark 1993: fig. 2c, d, e respectively) as figured: Md cutting edge smooth, Mx1 with sickle-shaped endopod, Mx2 scaphognathite with long posterior seta. Mxp1 ( Galil & Clark 1993: fig. 3a, b) with large epipod; exopod bearing distal segmented process tipped with setae. Mxp2 and Mxp3 ( Galil & Clark 1993: fig. 3c, d; see also Fig. 4H, I ): Mxp2 with long and slender exopod, Mxp3 with prominent toothed crest on mesial surface of ischium, three spines on lower border of ischium and merus, distal largest.

P1 ( Fig. 4C ) chelate, subequal. Ischium and merus with spines on lower border, propod with fixed finger nearly as long as palm, cutting edge bearing large and small round teeth; dactylus curved distally with denticles on distal half of cutting edge. P2 ( Fig. 4D ) chelate, unarmed, fixed finger and dactylus with pectinate cutting edge. P3-5 ( Fig. 4E, F ) simple, slender.

Branchial formula (after Galil & Clark 1993): single epipod on Mxp1-3 and P1-4; single podobranch on Mxp1-3 and P1-3; paired arthrobranch on Mxp3 and P1-4; single pleurobranch on P2-4.

Male Plp1 ( Fig. 4J ) slightly dilated subdistally bearing cluster of minute hooks on mesial border. Male Plp2 ( Fig. 4K ) with appendix interna and appendix masculina.

Uropod ( Fig. 4G ) about as long as telson, endopod with subdistal spine on lateral border and four or five dorsal spines; exopod with denticules and subdistal spine on lateral border, a suture near posterior border.

Colour

White ( Galil & Clark 1993).

Size

Holotype of cl. 11 mm, tl. 25.3 mm ( Galil & Clark 1993).

REMARKS

As the holotype is the only known specimen and in poor condition, the morphology of mouth appendages and the branchial formula are here given according to Galil & Clark (1993) (unchecked).

According to de Saint Laurent (pers. comm.), the material of “ Axiella n. sp. ”, a nomen nudum mentioned by Noël (1992: 80), from the Catalan coast, belongs to this species. It is deposited in the Institut de Ciènces del Mar de Barcelona (Dr Joan Cartes) but is not available for study at present. This material will be treated in a later work, with additional data on ecology and distribution.

Figures

FIG. 4. — Levantocaris hornungae Galil & Clark, 1993, holotype, from Haifa, Israel (NHML 1992: 608); A, abdomen, lateral view; B, anterior part of carapace; C, D, pereopod 1 and 2; E, F, pereopod 3 and distal part of pereopod 5; G, telson and uropods; H, I, maxilliped 3 and mesial view of ischium; J, K, pleopod 1 and 2. Scale bars: 2 mm.