Cenomanocarcinus, Van Straelen, 1936

Ossó, Àlex, 2017, New records of Palaeocorystoidea from the Iberian Peninsula and remarks on the taxonomic significance of the posterior margin of Cenomanocarcinus Van Straelen, 1936 and Hasaracancer Jux, 1971 (Decapoda; Brachyura; Cenomanocarcinidae), Zootaxa 4303 (2), pp. 273-283 : 275-276

Cenomanocarcinus sp. 1

( Fig. 2 )

Cenomanocarcinus sp. Ossó et al. 2015: 241, t. 1.

Locality and horizon. Traiguera (Baix Maestrat, Castelló, Spain), Leymeriella tardefurcata Biozone, Escucha Formation , early Albian.

Material examined and measurements (in mm). One incomplete specimen embedded within siliciclastic matrix, MGB 78174: width (from the basis of epibranchial spine) = 50 (25x2).

Description. Relatively large carapace, wider than long, cuticle smooth, appears to be subhexagonal, bearing three longitudinal ridges, one axial composed by the meso-, meta- and urogastric tubercles and the cardiac tubercle, and two branchial ridges. Orbito-frontal, anterolateral and posterior margin not preserved. Epibranchial spine subtriangular, strong, appears to be long. Posterolateral margin slightly concave, weakly rounded in cross section, post-epibranchial spine subtriangular, acute. Protogastric region swollen, two rounded tubercles aligned transversally; meso- and metagastric region defined by elongated tubercles, forming the axial ridge, slightly depressed by the cervical groove; urogastric region ridged longitudinally. Cardiac region narrow, ridged elongated. Intestinal region flattened, depressed. Hepatic region not completely preserved. Epibranchial region with a weak sigmoidal ridge that starts with a strong tubercle and ends at the level of last anterolateral tooth (epibranchial spine); two small tubercles at mid-length. Mesobranchial region defined by a coarse longitudinal ridge with blunt edges, depressed posteriorly and ending in a prominent broken spine. Metabranchial region depressed. Shallow branchiocardiac groove.

Remarks. The general appearance of the Traiguera specimen of Cenomanocarcinus , falls into the first morphological group reported by Ossó et al. (2015: 241) by its coarse and parallel branchial ridges. In particular, it recalls in many aspects his coeval C. cantabricus from the Albian of Cantabria ( Spain) and the Cenomanian C. boedekeri from the Cenomanian of Texas (USA), in having coarse axial and branchial ridges, presence of a postepibranchial tooth, similar pattern of epibranchial ridge and possibly a long epibranchial tooth. Nevertheless, the Traiguera specimen is incompletely preserved and lacks diagnostic characters such as: fronto-orbital, anterolateral, and posterior margins. The absence of those features impedes a specific assignation of this specimen or if it had been the case, the proposal of a new species for it.

Figures

FIGURE 2. Cenomanocarcinus sp. (sp. 1), From tardefurcata Biozone of Escucha Formation, early Albian. Traiguera (Castelló, Spain). MGB 78174, dorsal view of carapace. Abbreviations: ebs, epibranchial spines; pebs, post-epibranchial spine. Scale bar equal to 10 mm.