Graptocarcinus Roemer, 1887

Van, Barry W. M., Guinot, Danièle, Corral, José Carmelo & Artal, Pedro, 2012, Graptocarcininae n. subfam., an extinct subfamily of Dynomenidae Ortmann, 1892 (Crustacea, Brachyura, Podotremata), Zootaxa 3534, pp. 40-52 : 46-47

Genus Graptocarcinus Roemer, 1887

Type species. Graptocarcinus texanus Roemer, 1887 (= Cyphonotus integrimarginatus Wright & Wright, 1950 ), by monotypy.

Included species. G. bellonii Collins & Dieni, 1995 , G. maastrichtensis Fraaye, 1996 , G. m u i r i Stenzel, 1944, G. texanus Roemer, 1887 , G. urbasaensis n. sp..

Material examined. Graptocarcinus urbasaensis n. sp.: type series, see below. G. texanus Roemer, 1887 : MAB k.3208–3213 (ex collection K. Durney, Austin, Texas). Graptocarcinus sp. (as G. texanus ): MNHN-R.03275, cast of large carapace, original in Musée de Cherbourg, Upper Cretaceous, Maastrichtian, “craie à Baculites ”, Fresnelles (Manche), France. MNHN-A.32427 (coll. Milne-Edwards), small, mostly decorticated carapace, Upper Cretaceous, Cenomanian, Rouen (Ste-Catherine), Seine-Maritime, Haute-Normandie, France.

Remarks. Graptocarcinus is traditionally assigned to Dynomenidae ( Rathbun 1935: 41; Stenzel 1944: 550; Remy 1955: 162; Collins & Dieni 1995: 70; McLay 1999: 434; De Angeli & Garassino 2007: 24; De Grave et al. 2009: 27; Jagt et al. 2010: table 2; Schweitzer et al. 2010: 66; Breton & Collins 2011: 142; Karasawa et al. 2011: 542).

The Italian species Graptocarcinus bellonii is known from the Cenomanian type series ( Collins & Dieni 1995: figs. 2.1, 2.2), as well as from a better preserved Maastrichtian specimen ( De Angeli & Garassino 2007: fig. 1e). Differences in ornamentation between the type series and the additional specimen were ascribed to possible ontogenetic differences, the size difference being considerable ( De Angeli & Garassino 2007: 24). Jagt et al. (2010: 186) assumed that the claw figured by Collins & Dieni (1995: figs. 2.3, 2.5, 2.6) as “ Pagurinae genus indet.” is actually the claw of G. b e l l o n i.

Graptocarcinus maastrichtensis was described from a single, moderately preserved carapace from the type Maastrichtian of the Netherlands. It shows large orbits, a broadly triangular front, and a rounded pentagonal carapace outline ( Fraaye 1996: fig. 1). It may represent a juvenile specimen of the poorly known Stephanometopon granulatum Bosquet, 1854 , but more material is needed to verify this.

Graptocarcinus texanus was described by Roemer (1887) from four well preserved carapaces from the “upper Turonian” from Austin, Texas. The type series could not be located in Bonn (despite of a visit of first author together with J.W.M Jagt, NHMM, and R.H.B. Fraaije, MAB, in October 2011) and most probably is deposited in Wroclaw (formerly Breslau), Poland. Rathbun (1935: 41; pl. 10, figs. 13–15) figured an additional well preserved carapace, and Stenzel (1944: 551) translated and emended the original description by reporting the age of the type series as “Buda limestone of Comanche series, Cretaceous (lower Cenomanian)”. The species is reported from England ( Wright & Collins 1972), France ( Remy 1955), and Spain ( Van Straelen 1940), but well preserved material should be examined to verify if this material belongs to G. texanu s. Fraaye (1996: 463) provided additional information.

The other American species, Graptocarcinus muiri , was described from a single, isolated carapace from the Albian (middle Cretaceous) Taninul limestone of San Luis Potosí, Mexico ( Stenzel 1944). Vega & Feldmann (1992) stated this to be of Aptian age. It was synonymised with G. texanus by Wright & Collins (1972: 54) but subsequently Bishop (1986) and Fraaye (1996) treated them as separate species.

Guinot & Breton (2006: 610) commented that “the lower Cenomanian Necrocarcinus avicularis Fritsch in Fritsch & Kafka, 1887 ( Fritsch & Kafka 1887: 47 pro parte, pl. 10, fig. 12 only) might be included in Graptocarcinus Roemer, 1887 ”. This species is based on claws ( Fritsch & Kafka 1887: 47; Jagt et al. 2010: 185; table I) but two fragments of carapaces, clearly belonging to different genera, were figured ( Fritsch & Kafka 1887: pl. 10, figs. 12, 13). One of these fragments is described as ( Cancer ?) modestus ( Fritsch & Kafka 1887: 49, pl. 10, fig. 12) which Wright & Collins (1972: 54) questionably synonymised with Graptocarcinus texanus . Schweitzer et al. (2010: 80, 101) included N. avicularis in Necrocarcinus , while (C.?) modestus was erroneously listed under Cancer . Jagt et al. (2010: 185) assigned the chelae to the “form genus” Roemerus Bishop, 1983 , which was considered to be a dynomenid. Both the claws ( Fritsch & Kafka 1887: pl. 10, figs. 2, 10, 11) and the carapace fragment in figure 10, could belong to Graptocarcinus . The material, however, is fragmentary and disassociated, and no final conclusion can be drawn at present.

Claws of Graptocarcinus spp. may be differentiated from other fossil dynomenid claws by the presence of a distinct articulating bulge. Jagt et al. (2010: 179) stated that claw forms with oval depressions in both fingers for setae can be linked to “ Palaeodromites ” [to Distefania ] while forms lacking such depressions belong to Graptocarcinus or are closely allied dynomenids. The material described below confirms this view.