Cyclothyreus Remeš, 1895

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 : 50

Genus Cyclothyreus Remeš, 1895

Type species. Cyclothyreus strambergensis Remeš, 1895 , by monotypy ( Remeš 1895: 202).

Included species. C. cardiacus Schweitzer & Feldmann, 2009 , C. divaricatus Schweitzer & Feldmann, 2009 , C. latus (Moericke, 1889) , C. quadrophthalmus Schweitzer & Feldmann, 2009 , C. strangus Schweitzer & Feldmann, 2009 , C. transitorius ( Remeš, 1895) , C. reussi (Gemmellaro, 1869) , C. strambergensis Remeš, 1895 , C. tithonius (Gemmellaro, 1869) .

Remarks. Cyclothyreus was revised by Schweitzer & Feldmann (2009). Nine species were recognized, all of Tithonian (Late Jurassic) age, from central and eastern Europe ( Schweitzer & Feldmann 2009: table 1). These authors placed Cyclothyreus in Dromioidea, Dynomenidae sensu lato, recognising that the genus could not be accommodated within any of the existing subfamilies. Subsequently, Cyclothyreus was placed in Homolodromioidea, family Goniodromitidae Beurlen, 1932 ( De Grave et al. 2009: 28; Schweitzer & Feldmann 2010: 367; Schweitzer et al. 2010: 58).

Schweitzer & Feldmann (2009: 357) considered Cycloprosopon Lőrenthey in Lőrenthey & Beurlen, 1929, of which members have often been mixed with Cyclothyreus , as a distinct genus within the Goniodromitidae .

Cyclothyreus , known only from carapace material, can be attributed to the Graptocarcininae n. subfam. The carapace is oval in outline, tumid in both directions, the front widely triangular, the anterolateral margin well defined, without teeth, carapace regions undefined, only the cervical groove well defined, the subhepatic region conspicuously flat and smooth, with the cervical groove continuing ventrally. Cyclothyreus differs from Graptocarcinus in having a better defined cervical groove, which notches the lateral carapace margins. Cyclothyreus may be ancestral to Graptocarcinus .