Article: A taphonomic and diagenetic case study of a partially articulated ichthyosaur

A single carcase of the large Middle Jurassic ichthyosaurian Ophthalmosaurus sp. was rapidly decomposed in well-oxygenated bottom water of the Lower Oxford Clay Midlands basin. Parts of the soft tissues lying within anoxic sediments were subjected to slower rates of decay and portions of the integument are now preserved as replacements by bacterial and possibly fungal mats. Elements of the skeleton were encrusted with epibionts on their upper surfaces. Burial diagenesis has significantly affected some skeleton elements, with the infilling of voids with calcite, pyrite, and sphalerite. Rarely, bone phosphate has been replaced by pyrite. Compaction of bones and septarian cracking of surrounding concretionary mudstone has caused crushing and brecciation of trabecular bones. More massive bones with cross-sections capable of transmitting overburden pressures have resisted compaction.