Dromioidea

Abstract: A new genus and species of dromiacean crab, Lucanthonisia praemium, is recorded from the basal Belsele- Waas Clay Member (Boom Clay Formation; Rupelian, lower Oligocene) as formerly exposed at the Scheerders van Kerchove (SVK) clay pit near Sint-Niklaas, province of Oost-Vlaanderen (northwest Belgium). Extant dromioid crabs either carry foreign objects for camouflage (Dromiidae, Homolodromiidae) or are associated with corals (Dynomenidae). Although having been collected from the basal portion of the Belsele-Waas Clay Member which is rich in phosphatic nodules, preservation of the new form is such that long-term transport is unlikely. Therefore, the species is assumed to have lived hidden amongst and below such nodules, but it cannot be ruled out that it also carried sponges for defence. To our knowledge, representatives of such biota have not yet been recorded from the Boom Clay Formation. Dromilites eotvoesi from middle Miocene ('upper Badenian', Serravallian) strata in the Budapest area (central Hungary) is transferred to the new genus, Lucanthonisia. Lucanthonisia eotvoesi n. comb. differs from L. praemium, the type species, in having shorter, more anteriorly directed lateral spines, more closely spaced and less divergent rostral horns, better-developed epigastric nodes and a less convex carapace longitudinally. Preservation of a partial thoracic sternum in L. praemium gen. nov., sp. nov. allows comparison with dromioid families and tentative placement of the new genus, as well as the allied Basinotopus, in the Dynomenidae.

Abstract: Crustacea (dynomenid crabs and cirripedes) from the upper Cenomanian-lower Turonian nearshore, shallow-water bioclastic limestones to marly siltstones found along the southern and eastern margins of the Bohemian Cretaceous Basin (BCB) are described. Crabs are rather rare in this area, and mostly restricted to fragmentary pereiopods, i.e., isolated claws or dactyli. In view of the confused taxonomy of isolated claws, their proper identity could not be determined; they were mostly referred to the necrocarcinid genus Necrocarcinus Bell, 1863. A recent re-examination of material deposited in the collections of the National Museum (Narodni Muzeum, Prague), and of new finds, has revealed that all allegedly necrocarcinid pereiopods and nearly all carapaces from these shallow-water strata actually belong to the dynomenid Graptocarcinus Roemer, 1887 (carapaces) and the ‘form genus’ Roemerus Bishop, 1983 (isolated claws). Here we present a summary report of occurrence of these dynomenid genera in the BCB. Cirripedes are more abundant, yet all available material is in the form of disarticulated, isolated capitular plates, which is typical for almost all Mesozoic thoracicans. More than 400 capitular plates of stalked barnacles have been discovered in sieve residues during the last decade. A study of newly recovered specimens, together with a revision of material contained in museum collections, has resulted in the description of a new species of the genus Zeugmatolepas Withers, 1913 and confirmation of the occurrence of ‘Scillaelepas’ conica (Reuss, 1844), Titanolepas tuberculata (Darwin, 1851), Smilium? parvulum (Withers, 1914), Cretiscalpellum glabrum (Roemer, 1841), C. striatum (Darwin, 1851) and Arcoscalpellum angustatum (Geinitz, 1843).

Abstract: The crustaceans from the marine Berivotra Formation, dated as late Cretaceous, from 50 km south of Mahajanga, Madagascar contains macrurans, brachyurans and thalassinideans. Two brachyuran families, Raninidae and Dynomenidae, were previously identified with the genera Notopocorystes, Caloxanthus, Titanocarcinus, Xanthosia, and Dromiopsis. Fragmentary material now also allows the recognition of Dromioidea, Calappoidea and Xanthoidea.