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Taphonomy of exceptionally preserved crustaceans from the Upper Carboniferous of southeastern Ireland

Patrick J. Orr, Derek E. G. Briggs and Stuart L. Kearns
Taphonomy of exceptionally preserved crustaceans from the Upper Carboniferous of southeastern Ireland
Palaios (May 2008) 23 (5): 298-312


The Castlecomer Fauna, a Konservat-Lagerstaette from the Upper Carboniferous of Ireland, is dominated by two species of exceptionally preserved spinicaudatan conchostracan branchiopod crustaceans; over 300 articulated specimens are known from short lengths of core from two boreholes. The spinicaudatans were entombed at various angles to bedding in thin event beds deposited in a paralic environment. Cuticle is the only tissue represented. The fossils are essentially two-dimensional as specimens collapsed following decay-induced loss of the structural strength of the cuticle. Some three-dimensionality was retained, however, as clay-grade material, probably sediment, infiltrated the carapace during or after burial, preventing the valves from being compacted to the same plane as the body of the specimen. Cuticle-lined voids created by decay of the labile tissues (notably within the tubelike antennal rami) were lined or infilled by authigenic clay minerals that were subsequently metamorphosed. The antennae, mandibles, distal parts of the claspers, and the telson are preserved in excellent detail, often retaining all or most of their original relief. Other anatomical features (antennal protopods, head, proximal part of claspers, trunk appendages) are usually preserved in two dimensions, either as a film of carbon or a dark-colored stain. The antennules, maxillules, and maxillae are rarely preserved. Decay experiments confirm that this variation reflects differences in the recalcitrance (thickness and degree of sclerotization) of the cuticle that covered different parts of the body. Complete decay of certain appendages precedes appreciable deterioration in the morphology of others. Some of the disparity exhibited by exceptionally preserved fossil arthropods is likely to be taphonomic rather than biological in origin.

ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 23
Serial Issue: 5
Title: Taphonomy of exceptionally preserved crustaceans from the Upper Carboniferous of southeastern Ireland
Affiliation: University College Dublin, School of Geological Sciences, Dublin, Ireland
Pages: 298-312
Published: 20080501
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
References: 39
Accession Number: 2008-086493
Categories: Invertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. cols., geol. sketch map
N52°47'60" - N52°47'60", W07°31'00" - W07°31'00"
Secondary Affiliation: Yale University, USA, United StatesUniversity of Bristol, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 200826
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