Paragalene longicrura
Creators: name: Castro, Peter
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Progeryonidae
Paragalene
Paragalene longicrura

description: Paragalene longicrura (Nardo, 1868)   
(Figs. 6–8)  
 Eriphia longicrura Nardo, 1868: 302, pl. 13 fig. 1.   
 Paragalene neapolitana Kossmann, 1878: 253.   
For complete synonymy, see d’Udekem d’Acoz 1999: 241; Ng & Manuel-Santos 2007: 68.  
 Material examined. 2 ♂♂, 32.4 x 41.7 mm, 33.0 x 43.7 mm (NHM 1959.5.26.187–188), Bay of Naples, collected by Zoological Station at Naples, Italy.   
 Description. Carapace hexagonal (Fig. 6A; also see Türkay 1976b: fig. 1; González Pérez 1995: figs. 139, 140); front lamellar, marked by median notch bordered on each side by narrow prominence plus wide concave margin ending in a prominence; notch between front, supraorbital border. Orbits (Fig. 6B) short, spherical, not expanded on outer portion; triangular, granular outer orbital tooth; supraorbital borders short, curved, with large granules, notches absent. Anterolateral borders (Fig. 6A) curved; posterolateral borders long, nearly straight. Dorsal surface of carapace convex anteriorly, granular with granules larger, conspicuous along anterior border. Granular ridge across hepatic region. Elevated protogastric region with 2 granular ridges along anterior margin, deep bifurcated sulcus medially. Branchial region with short, transverse ridge, Cardiac region with 2 shallow, curved grooves. Outer orbital angle with granular margin; anterolateral margin with 4 teeth; anteriormost 2 granular, obtuse; third tooth (largest) curved upward, granular, with smooth, acute apex; fourth straight, granular with smooth, acute apex (Fig. 6A). Basal antennal article short, mobile, almost closed by extension of carapace margin, thus distalmost (third) article almost reaches front (Fig. 6 C, E). Eye peduncle short, cornea spherical, large, expanded distally (Fig. 6B). Suborbital border with large, granular, acute inner tooth, similar median tooth (Fig. 6C, E). Anterior border of endostome well demarcated from buccal cavern, ridges faint but clearly defined. Third maxillipeds completely close buccal cavern; anterior outer margin conspicuously expanded, rounded. Endostomial ridge distinct, granular. No visible stridulating mechanism.   
Cheliped (P1) fingers slender, equal to or less than half propodus length, dark coloured (Fig. 7A, B). Propodus dorsally granular; carpus with 2 acute teeth on inner margin (Fig. 6A). P2–P5 meri, carpi, propodi long, slender; dorsal margins unarmed; dactyli long, slender, setose (Fig. 6A).  
Thoracic sternum relatively narrow (Figs. 6D, 7E). Sternites 1, 2 completely fused, no trace of suture; S2/ 3 complete, deep; S3/4 complete but medially shallow; S4/5, S5/6 medially interrupted; S6/7, 7/8 complete; median longitudinal groove on sternites 7, 8 (Fig. 7G). Somite 3 of male abdomen covers thoracic sternal space between P5 coxae, thoracic sternite 8 not visible (Fig. 7D, F). Episternites 4–6 laterally expanded (Fig. 7E, F); episternite 7 expanded laterally and posteriorly, reaching and partially covering anterior part of P5 coxa but not penis (Fig. 7G). Penis coxal, small, short distal extension, emerging just anterior to condyle; very broad, soft proximal expansion (Fig. 7G). Sterno-abdominal cavity relatively deep, reaching to before margin of S3/4 (Fig. 7E). Press button of male abdomen locking mechanism on posterior half of sternite 5, closer to margin of sternite 6 (Fig. 7E).  
Male abdomen with 5 freely-movable somites (somites 3, 4 fused) plus telson, relatively narrow; somite 1 exposed, not covered by posterior carapace margin, transversely narrow, sublunate in shape; somites 4–6 sharply decreasing in length from somite 3 (widest somite) (Fig. 7D, F). Telson subequal, slightly wider than long (Fig. 6D). G1 very slender, spinous, slightly dilated apex (Fig. 8A, B). G2 slightly longer than G1, flagellum as long as proximal part; thin, lateral projections; pointed, serrated apex (Fig. 8C, D).  
Female specimens unavailable for description.  
 Remarks. Paragalene longicrura is rarely collected and very little is known about its biology. It appears to live in relatively shallow water (usually 20–30 m but also as deep as 160 m) and mostly on hard bottoms, including sea caves (see d’Udekem d’Acoz 1999: 241; Türkay 1976a: 70, pl. 3; González Pérez 1995: 199, colour figs. 139, 140 for reviews of its ecology and geographical distribution).   
 Distribution. Mediterranean Sea and eastern Atlantic Ocean (Madeira and Canary Islands).   
 Comparative material. Progeryon mus Ng & Guinot, 1999: holotype male (38.6 x 46.5 mm), 1 paratype female (ZRC 1997.442 – 443), Nihoa Island, Hawaii, 441 m depth, coll. 1979.
description: Published as part of Castro, Peter & Ng, Peter K. L., 2008, Rhadinoplax, a new genus of Progeryonidae Števčić, 2005, for Carcinoplax microphthalmus Guinot & Richer de Forges, 1981, and a redescription of Paragalene longicrura (Nardo, 1868) (Crustacea: Decapoda: Brachyura: Goneplacoidea), pp. 53-68 in Zootaxa 1777 on pages 63-66