Joeranina gaspari, Van Bakel & Guinot & Artal & Fraaije & Jagt, 2012

Van Bakel, Barry W. M., Guinot, Danièle, Artal, Pedro, Fraaije, René H. B. & Jagt, John W. M., 2012, A revision of the Palaeocorystoidea and the phylogeny of raninoidian crabs (Crustacea, Decapoda, Brachyura, Podotremata) 3215, Zootaxa 3215 (1), pp. 1-216 : 40

Joeranina gaspari n. sp.

( Figs. 11C, E–F ; 12A–D )

Diagnosis. Carapace small, subhexagonally elongated, widest at level of epibranchial spine; axial carina weak; front with 4 divergent spines at distal portion; orbital margin broad, with 2 deep supramarginal fissures, bounding robust central tooth with triangular upper margin; lateral margins weakly arched, with 2 long spines at level of hepatic region; cervical groove well-defined; dorsal regions scarcely defined, subtle elongated swellings in hepatic region, admedial triangular swelling in protogastric region, intestinal region elongated, somewhat inflated, bounded by shallow grooves; dorsal surface with fine granules, branchial regions pitted.

Derivation of name. In honour of Gustavo Gaspar (Navarra, Spain), who provided the first specimens to one of the authors (PA).

Material examined. Holotype, a near-complete carapace ( MGSB75294 ), partially decorticated; paratypes, a carapace, lacking the front, cuticle fairly complete ( MGSB75295 a); a fragmentary carapace with well-preserved right portion ( MGSB75295 b), all from 1 km north of Egiarreta (Navarra), from red-coloured Albian beds (Instituto Geológico de España 1987). Additional paratypes are a near-complete carapace, lacking the front ( MGSB75296 a); an anterior half of a carapace ( MGSB75296 b); a partial ventral side ( MGSB75296 c), all with only few fragments of cuticle preserved, from approximately 1.5 km north of the village of Irurtzun (Navarra), from Albian limestones ( Instituto Geológico de España 1978).

Description. Carapace small, subexagonally elongated, weakly convex in both directions; maximum width at level of epibranchial spine; orbitofrontal margin broad, about three-quarters of maximum width; axial carina weakly marked; orbits large, supraorbital margin with 2 deep, rather open fissures, supraorbital tooth broadly triangular, extraorbital tooth robust, with long, acute, conical extraorbital spine; front projected, narrow, with 4 divergent spines at distal portion, the posterior ones fairly long; lateral margins of carapace gently arched, anterolateral margin short, with 2 long, conical, forwardly directed spines at level of hepatic region, and 1 spine at level of epibranchial region; posterolateral margins longer, anteriorly with small, forwardly directed spine, nearly straight, diverging, sharp with subtle rim; posterior margin shorter than orbitofrontal width, slightly concave; dorsal regions poorly defined; cervical groove well-defined, complete, medially broadly U-shaped, laterally as an inverted Vshape, clearly notching carapace margin; subtriangular admedial lobe of protogastric region weakly salient, joining small hepatic protuberance; epibranchial region with subtle interbranchial scar; cardiac region relatively narrow, bounded by subtly arched branchiocardiac grooves; dorsal surface densely and finely granular over entire carapace, with some pits on branchial regions.

Remarks. Joeranina gaspari n. sp. can be easily distinguished from all congeners on the basis of the weak axial carina, the conspicuously long lateral and frontal spines, the triangular central tooth of the supraorbital margin, and the urn-shaped frontal furrows. The dorsal surface of J. gaspari n. sp. presents an arrangement of very fine granules that is denser than in other species. Joeranina Syriacus n. comb., which is based on a single, rather incomplete specimen, also has a stronger base of the lateral spines; J. platys presents a wider anterior carapace; J. paututensis is distinguished by having more marked carapace grooves and J. broderipii presents more pronounced hepatic and protogastric protuberances.

The density of granulation and definition of regions of the dorsal carapace varies between specimens from Egiarreta and Irurtzun. Discovery of better-preserved material might lead to the conclusion that two species are present.

Figures

FIGURE 11. A, B, D, Joeranina broderipii (Mantell, 1844) n. comb. (Palaeocorystidae); A, MAB k. 2894 (indeterminate sex), Albian, Escalles (Calais, northern France), dorsal view of carapace; B, MAB k. 2879 (female), Albian, Folkestone (Kent, southern England), ventral view showing thoracic sternum and bases of pereiopods; D, MAB k. 2915 (female), Albian, Escalles (Calais, northern France), ventral view showing thoracic sternum and appendages; C, E, F, Joeranina gaspari n. sp., Albian, Irurtzun (Navarra, northern Spain), MGSB75296b (C; paratype), dorsal view of anterior portion of carapace; MGSB75296a (E; paratype), dorsal view of carapace, and MGSB75296c (F; paratype), ventral view showing posterior portion of thoracic sternum. Scale bars: 5mm.

FIGURE 12. Joeranina gaspari n. sp. (Palaeocorystidae), Albian, Egiarreta (Navarra, northern Spain); A, C, MGSB75294 (holotype), dorsal view of carapace, and detail of rostrum; B, MGSB75295b (paratype), right portion of carapace, dorsal view; D, MGSB75295a (paratype), dorsal view of carapace. Scale bars: A, B, D: 5mm; C: 2mm.