A NEW EARLY OLIGOCENE CRAB (DECAPODA, BRACHYURA, DROMIACEA) FROM NORTHWEST BELGIUM, WITH COMMENTS ON ITS PALAEOBIOLOGY
Oertijdmuseum De Groene Poort, Bosscheweg 80, NL-5283 WB Boxtel, the Netherlands; E-mail: barryvanbakel@gmail.com [corresponding author]
Museo Geológico del Seminario de Barcelona, Diputación 231, E-08007 Barcelona, Spain; E-mail: partal@optimus.es
Oertijdmuseum De Groene Poort, Bosscheweg 80, NL-5283 WB Boxtel, the Netherlans; E-mail: info@oertijdmuseum.nl
Natuurhistorisch Museum Maastricht (SCZ), de Bosquetplein 6-7, NL-6211 KJ Maastricht, the Netherlands; E-mail: john.jagt@maastricht.nl
Abstract
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.