Contributions to Zoology, 72 (2/3) (2003)Christian Neumann; John W.M. Jagt: A ?carcineretid crab from Lower Turonian (Cretaceous) black shales of Misburg, Hannover area (Germany)

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The brief description is distilled from observations on the specimen in question made by Professor R.M. Feldmann (Kent State University, Kent, Ohio), during an earlier visit to the Humboldt Museum, and ourselves. Preservation is poor (Fig. 1), with detail lacking over most of the animal; it appears that the ventral surface is exposed, with the length and width of the venter being about equal, c. 26 mm. It might represent a female with an ovoid telson, 13.7 mm wide, 10.7 mm long. Chelipeds are equal and robust, with propodus and fixed fingers at least 27 mm long, and the proximal portion of the hand missing. Upper and lower surfaces show granules or very small spines, and the fixed finger of the left claw has domed denticles that increase in size proximally. The merus of ?third pereiopod is 23.9 mm long, 5 mm wide proximally, 3.7 mm wide distally; merus of fourth pereiopod equal to third, dactylus lanceolate. Pereiopod 5 with merus 10.8 mm long, c. 4 mm wide; carpus, propodus, dactylus flabelliform. Carpus 7.5 mm long, 5.5 mm wide; propodus 12.5 mm long, 8.0 mm wide; dactylus 5.2 mm long, 2.9 mm wide.


Fig. 1. Specifically indeterminate ?carcineretid; Hannoversche Portland Cement II, Misburg (Hannover area, Germany), Lower Turonian (black shale facies) A, uncoated, B, whitened with ammonium chloride sublimate prior to photography. Scale bar in mm.

The accompanying label states, ‘cf. Portunus holsatus Fabricius. Turonian Black shales; Hannoversche Portland Cement, Fabrik II. Turon; Sapropel-Lage, Misburg; leg. Schumacher 22.11.75. The specimen is in the G. Ernst Collection, formerly at the Freie Universität Berlin, now at the Museum für Naturkunde (Humboldt Universität, Berlin). The late Dr R. Förster appears to have checked the specimen (30 January 1976) cursorily, and noted: ‘Portunus sp., Schwimmkrabbe, Unterseite’ (= Portunus sp., swimming crab, lower side).