Notopocorystes McCoy, 1849

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 : 40-44

Genus Notopocorystes McCoy, 1849

Notopocorystes McCoy, 1849: 169 .

Palaeocorystes Bell, 1863: 11 .

Type species. Corystes stokesii Mantell, 1844 , by subsequent designation of Withers (1928) (= Notopocorystes mantelli McCoy, 1849 ).

Diagnosis. Small-sized carapace, subhexagonally elongated in outline, maximum width at epibranchial spine, dorsal surface fairly convex in both directions; cervical groove marking two different slopes; axial ridge present along complete carapace, with row of single or double ( N. bituberculatus ) tubercles; orbits rather narrow for the family, with 2 supramarginal fissures; front narrow, trapezoidal, bifid, with 2 distal, 2 subdistal spines, the posterior ones strongly reduced; anterolateral margins short, arched, with 3 conical spines well separated by cervical notch: 2 anterior at level of hepatic region, one posterior at level of epibranchial region; posterolateral margins longer, with small mesobranchial spine behind discrete branchial notch, first portion sharp, usually with denticles, posterior portion rounded; posterior margin fairly concave, shorter than orbitofrontal margin; dorsal regions well defined by swellings, grooves, lobes of regions with tubercles; hepatic region with single, relatively small tubercle; protogastric lobe usually with admedial arched row of tubercles; cervical groove well-defined as thin line, complete, sinuous, medially U-shaped, gastric pits present in axial portion; branchial groove well-defined, lateral, fairly long. Dorsal surface covered by fine, dense granules (upright nodes), may be more widely spaced and larger posteriorly ( N. normani ). Pterygostome large, with blunt crests, buccal margin fairly concave, with broad buccal collar; thoracic sternum narrow, elongated, narrowing backwards, never connected to pterygostome; sternites 1 and 2 fairly narrow, situated at lower level; sternite 3 subpentagonal, with rather deep incision at base of lateral margins; sternite 4 subtrapezoidal with lateral margins long, oblique, somewhat concave, episternites suboval, posteriorly bounded by crescent-shaped suture 4/5; sternite 5 with short, arched grooves, episternites 5 long, directed obliquely, with distally a notable double peg for abdominal holding, suture 5/6 arched; sternite 6 narrow, episternites elongated, directed backwards, with arched suture 6/7; sternites 7, 8 reduced, tilted; spermathecal apertures elongated, at extremity of suture 7/8; all sternal sutures opened, directed forwards; abdomen narrow, completely filling the sterno-abdominal depression in both sexes, all abdominal somites free, somites 1‒6 with raised axial portion, somites 1, 2 restricted for P5 coxae, somites 3‒5 with central tubercle, somite 6 long; telson reaching sternite 4; mxp3 elongated, in oxystomian condition: coxae large, flabelliform, basis-ischium fused, long, smooth, exopod slender, long, endopod with shallow longitudinal groove; P1 with chelae homochelous, homodontous, tuberculate, upper, lower margins spinose, outer surface of merus with sharp distal crest; P2‒P4 long, flattened, upper and lower margins granulate; P5 much reduced, subdorsal. Ventral regions, anterior portion of thoracic sternum densely granular.

Species included. Notopocorystes bituberculatus Secretan, 1964 , N. normani ( Bell, 1863) [as Palaeocorystes ], N. praecox Wright & Collins, 1972 [as Notopocorystes (Notopocorystes) stokesii praecox ], N. serotinus Wright & Collins, 1972 [as Notopocorystes (Notopocorystes) stokesii serotinus ], N. stokesii ( Mantell, 1844) [as Corystes ] and N. xizangensis Wang, 1981 .

Material examined. Notopocorystes bituberculatus: MNHN F.R 03951 (holotype), incomplete carapace with associated sternum, lower Albian , Malandriandro , Sitampiky region , Mahajanga Basin , Madagascar (see Fig. 10C, F ; Charbonnier et al. in press). N. serotinus: MAB k. 2872, dorsal carapace (indeterminate sex; plaster cast of specimen in L. de Putter Collection), Albian , Escalles (Calais, northern France). IRScNB unregistered, Van Straelen Collection, drawer 218, approximately 80 well-preserved specimens with preservation of ventral characters, upper Albian , Cambridge Greensand, Cambridge (southern England) . N. normani: NHM In. 44346, carapace with cheliped, Lower Chalk , Cenomanian, Dover (Kent, southern England) . N. stokesii: MAB k. 2870, carapace with ventral surface without abdomen (indeterminate sex); MAB k. 2873, carapace with thoracic sternum with spermathecae and ‘double peg’ for abdominal locking mechanism (female); MAB k. 2874, carapace, thoracic sternum, mxp3, with gonopore on P3 coxa (female); MAB k. 2889, carapace with thoracic sternum, mxp3 and pereiopods (juvenile female); MAB k. 2900, carapace infested on both sides by parasitic isopod (plaster cast of specimen in L. de Putter Collection; indeterminate sex); MAB k. 2906, carapace with mxp3 (indeterminate sex); MAB k. 2907, carapace with thoracic sternum, mxp3 and bases of pereiopods (female); Albian, Escalles (Calais, northern France) . MNHN-B.14179, 2 specimens with ventral characters preserved; MNHN-B.14186, specimen in situ with chelipeds preserved; MNHN-B.14186, 7 specimens with ventral characters preserved, 1 specimen in situ with chelipeds preserved (A. Milne-Edwards Collection ); MNHN-R.03311, carapace; MAB k. 2901: partial carapace and thoracic sternum (leg. B. Fraaije; indeterminate sex); Albian, Folkestone (Kent, southern England) . IRScNB unregistered, Van Straelen Collection, drawer 218, approximately 200 specimens, most with remains of abdomen, thoracic sternum and pereiopods; MNHN-B.17958, 8 specimens with ventral characters preserved; Cambridge Greensand, upper Albian , Cambridge (southern England) . MAB k. 2890, partial carapace with thoracic sternum and telson (indeterminate sex); MAB k. 2897, partial carapace and thoracic sternum showing double peg (indeterminate sex), middle Albian, Pargny (northern France) . MAB k. 2924, carapace with well-preserved thoracic sternum showing spermathecae, pterygostome and bases of appendages (ex G. Van den Eeckhaut Collection; female); middle Albian, Lac du Der (northern France) . MNHN-B.14633, carapace (indeterminate sex); Albian, St. Dizier , Haute-Marne, northern France .

Notopocorystes is distinguished from all other palaeocorystid genera in having a more convex carapace, with relatively narrow orbitofrontal margin; a wider front; tuberculate, vaulted regions; and a distinct, tuberculate carina. All species assigned here to Notopocorystes share constant dorsal and (when preserved) ventral features as diagnosed here. Differences among these species mainly involve the number and placement of the tubercles on the dorsal surface, orbitofrontal width and the development of the longitudinal crest (see Wright & Collins 1972; Collins 1997). Of the seven species of Notopocorystes listed by Tucker (1998: 333), N. japonicus , from the Cenomanian to Santonian of Japan, is excluded and transferred to Joeranina n. gen. on account of its less convex carapace, absence of tubercles on the dorsal surface, possession of characteristic hepatic and protogastric lobes, and typical frontal furrows. Notopocorystes xizangensis was established on the basis of a single, incomplete and badly weathered carapace. Material recently described from Aptian-Albian strata in Iran ( Yazdi et al. 2009) and assigned to this species appears to be more elongated. New and better-preserved material might reveal that two distinct taxa are involved.

Figures

FIGURE 10. Palaeocorystids from Madagascar; A, B, Cretacoranina denisae (Secretan, 1964), lower Campanian, Ampolipoly-Antsirasira region; (A; paratype, labelled Notopocorystes australis Secretan, 1964; MNHN R03878) and MNHN R03875 (B; holotype); C, F, Notopocorystes bituberculatus Secretan, 1964, MNHN R03951 (holotype), Albian, Malandriandro, dorsal view of carapace, and ventral view showing thoracic sternum; D, E, Joeranina sp., MNHN R03930 (indeterminate sex), Cenomanian, Antsirane, dorsal view of fragmentary carapace and ventral view; G, H, Ferroranina australis (Secretan, 1964) n. comb., MNHN R03874 (G; holotype), lower Campanian, Berere, dorsal view of carapace, and MNHN R03903 (H; paratype), lower Campanian, Ampolipoly-Antsirasira, dorsal view of carapace. Scale bars: 5mm.