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BRITISH CHALK CRUSTACEANS |
| Introduction |
The Crustaceans are a major group within the Arthropods; invertebrates bearing a toughened exoskeleton, segmented bodies and jointed limbs. Crustaceans are distinguished from other arthropods by their particular arrangement of antennae and appendages at the front of the body.
Malacostracans (e.g. Palaeastacus sussexensis) are primarily represented by lobsters (Macrura) and occasional crabs (Brachyura) and water-lice (Isopoda) in the British Chalk. Although the malacostracans of the chalk seas often possessed a robust and extensive exoskeleton, producing a number of moults during a lifetime, they are scarcely found preserved as body fossils (except for crabs in the sandy facies of the SW). Their supposed burrow networks, however, are frequently encountered, suggesting that their general absence is a preservational effect. Isolated chelipeds (pincers) of Palaeastacus sussexensis from the Grey Chalk form the majority of museum specimens. Most other species are rarely seen, and complete and articulated specimens are highly unusual. Small, isolated dactyls, probably assignable to the Brachyura, may be found with reasonable frequency in the Grey Chalk, though their size makes them quite inconspicuous. (Terminology).
Cirripedes (e.g. Arcoscalpellum fossula) are represented by goose-barnacles (barnacles mounted on an elongate fleshy stalk) in the British Chalk. The protective calcareous plates of the capitulum which encloses the animal are not uncommon, but they typically occur isolated and their small size and simplistic shape means they are generally overlooked. Articulated individuals are amongst the rarest of British Chalk fossils. (Terminology).
| Species |
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| Palaeastacus sussexensis | Hoploparia sp.? |
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| Enoploclytia leachii | Glyphea willetti |
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Palaega |
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Cirripedes (Goose Barnacles) |
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| Cretiscalpellum | Stramentum |
| References |
BELL, T. 1863. A monograph of the fossil malacostracous Crustacea of Great Britain. Pt. II, Crustacea of the Gault andGreensand. Palaeontographical Society, London.
DIXON, F. 1850. The Geology and Fossils of the Tertiary and Cretaceous Formations of Sussex, (private publication) London.
MORRIS, S. F. 1980. Catalogue of the Type and Figured Specimens of Fossil Crustacea (excl. Ostracoda, Chelicerata, Myriapoda and Pycnogonida in the BritishMuseum (Natural History). British Museum (Natural History), London.
WITHERS, T. H. 1935. Catalogue of fossils Cirripedia in the Department of Geology, II, Cretaceous, British Museum (Natural History), London.
WOODS, H. 1922. A monograph of the fossil macurous Crustacea of England, Palaeontographical Society.
WOODWARD, H. 1878. On Meyeria Willettii, a new macrurous Crustacea from the Chalk of Sussex. Geological Magazine, Decade 2, 5, 556-558.
WRIGHT, C. W., & COLLINS, J. S. 1972. British Cretaceous Crabs, Palaeontographical Society.
