Cenomanocarcinus beardi Schweitzer, Feldmann, Fam, Hessin, Hetrick, Nyborg & Ross, 2003

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 : 54

Cenomanocarcinus beardi Schweitzer, Feldmann, Fam, Hessin, Hetrick, Nyborg & Ross, 2003

( Figs. 17A–D ; 18F )

Material examined. MAB k. 2969: cast of paratype ( GSC 124821 ), provided by C.E. Schweitzer, March 2007 (see Schweitzer et al. 2003a: 35, fig. 12.1) ; MAB k. 2544, k. 2880, k. 2916, k. 2917, Woodbine Formation, Cenomanian, Creek in Wagner Park , southwest Freud Prairie, Texas ( U.S.A.) .

Emended description. Pterygostome large, with blunt, granular crest, buccal margin concave, rimmed. Mxp3: exopod long, slender, lateral margin gently arched; endopod ischium slightly longer than exopod, medially weakly excavated. Thoracic sternum narrow, elongated, with medial sterno-abdominal depression; sternite 3 small, crown shaped, sternite 4 trapezoidal, rather short; episternites 4 wide, large, subtriangular, anteriorly with distinct gynglyme for P1; sternites 5–8 equal in width, with flat, undivided medial surface, raised, posterolaterally directed episternites; sutures 4/5–6/7 sinuous, directed forwards; suture 7/8 long, straight, terminating in oval spermathecal aperture.

Remarks. Discovery of a specimen with preserved ventral characters necessitates an amendment of the description; dorsal carapace was described by Schweitzer et al. (2003a: 38). Guinot et al. (2008: 38) described the morphology of a specimen (MAB k. 2544) referred to as Cenomanocarcinus aff. beardi . It has spermathecae (aperture preserved at one side), hence confirming the podotreme status of Cenomanocarcinidae . This particular specimen is here assigned beyond doubt to C. beardi . All features of the dorsal carapace of the examined Texas material compared well with the type series. The lack of a lateral tooth between the fourth anterolateral tooth and the epibranchial spine, the strongly produced epibranchial spine, the rounded cross section of the posterolateral margin, which is devoid of spinules or teeth (except near the posterior corner), and the tuberculation of the branchial crests distinguish specimens of the new species from both C. inflatus and C. vanstraeleni . The record of C. beardi from the Cenomanian of Texas marks the oldest occurrence of the species and a southerly range extension. Ventral features are described for the first time for this species, which thus far represents the only example of a spermatheca in Cenomanocarcinidae .

Figures

FIGURE 17. A–D, Cenomanocarcinus beardi Schweitzer, Feldmann, Fam, Hessin, Hetrick, Nyborg & Ross, 2003a (Cenomanocarcinidae); A, D, MAB k. 2544 (female), Cenomanian (Woodbine Formation), Wagner Park, Texas (U.S.A), dorsal view of carapace, and ventral view showing thoracic sternum and mxp3; B, C, MAB k. 2916 and k. 2917 (both indeterminate sex), partial carapaces, same locality and provenance; E, F, Cenomanocarcinus cantabricus n. sp., Albian, Cabo de Ajo (Cantabria, Spain); E, MGSB75431 (holotype; ex Manuel Díaz Collection), dorsal view of carapace; F, MGSB75423 (paratype; ex Pedro Artal Collection), dorsal view of carapace. Scale bars: A-D: 5mm; E, F: 10mm.

FIGURE 18. A, D. Cenomanocarcinus inflatus Van Straelen, 1936 (Cenomanocarcinidae), MNHN J08587 (lectotype), photograph of MAB k. 2968 (cast), upper Cenomanian, Butte de Gazonfier, Le Mans (northwestern France); dorsal and left lateral views (direction of photography in D indicated by arrow in A); B, C, E, Cenomanocarcinus vanstraeleni Stenzel, 1945, MAB k. 2909 (B, C; indeterminate sex), upper Albian-lower Cenomanian (Pawpaw Formation), Tarrant County, Texas (U.S.A); dorsal and left lateral views (direction of photography in C indicated by arrow in B); MAB k. 2885 (E; indeterminate sex), dorsal view of carapace; F, Cenomanocarcinus beardi Schweitzer, Feldmann, Fam, Hessin, Hetrick, Nyborg & Ross, 2003a, MAB k. 2880 (indeterminate sex), Cenomanian (Woodbine Formation), Wagner Park, Texas (U.S.A), dorsal view of carapace. ebs, epibranchial spine; pbs, posterobranchial spine. Scale bars: 10mm.