Contributions to Zoology, 72 (2/3) (2003)Barry W.M. van Bakel; John W.M. Jagt; René H.B. Fraaije; Yvonne Coole: New data on the crab Binkhorstia ubaghsii (Late Maastrichtian; NE Belgium, SE Netherlands)

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Introduction

Carcinologists dealing with fossil crabs are often faced with difficulties in classifying their material. With only a single or a handful of specimens available, more often than not consisting of only (partial) carapaces, dorsal carapace characters are the sole features to go on. Classification of extant crabs mostly cannot be applied, since ventral morphology is here of prime importance (Guinot, 1977 , 1978). Having come to realize that carapace characters may overlap in representatives of unrelated families, in the past decade paleontologists have used the few cases in which crabs are preserved with well-preserved ventral parts with much success (Karasawa, 2003, Guinot & Tavares, 2001).

Binkhorstia Noetling, 1881, known exclusively from Upper Maastrichtian deposits in the type area of the Maastrichtian Stage (SE Netherlands, NE Belgium), has been placed in different families by various authors. Glaessner (1980) erected the family Torynommidae (Cyclodorippoidea), and included Withersella Wright & Collins, 1972 and Binkhorstia. Withersella was originally placed in the Carcineretidae Beurlen, 1930, and together with Binkhorstia again assigned to the Carcineretidae by later authors (Collins et al., 1995; Fraaye, 1996; Wright, 1997; Jagt et al., 2000). Many new species of and new data for the largely western Tethyan Carcineretidae have been described in the past two decades (Feldmann et al., 1999; Feldmann & Villamil, 2002; Vega & Feldmann, 1991; Vega et al., 1995; Vega et al., 1997; Vega et al., 2001). Feldmann & Villamil (2002) included five genera in the Carcineretidae, namely Carcineretes Withers, 1922, Branchiocarcinus Vega et al., 1995, Mascaranada Vega & Feldmann, 1991, Ophthalmoplax Rathbun, 1935 and Woodbinax Stenzel, 1952. They suggested that Binkhorstia and Withersella should be retained in the Cyclodorippidae Ortmann, 1892.

FIG2

Fig. 1. Binkhorstia ubaghsii (van Binkhorst, 1857); Upper Nekum Member (Maastricht formation, Late Maastrichtian) of CBR-Romontbos quarry, Eben Emael (NE Belgium). 1, Right cheliped. 2, Left cheliped of the same specimen. 3, Dorsal view of this specimen, showing complete carapace, both claws and limb fragments. 4, Dorsal view. 5, Ventral view, showing the delicate preservation.