A Cambrian Phosphatocopid (Geology Section)

A Zoom talk by Rich Reynolds.

Full title: “An Exceptionally Well Preserved Phosphatocopid (Arthropoda: Phosphatocopida) from the Late Cambrian USA”.

Phosphatocopids are small bivalved crustaceans reported from Cambrian strata. The earliest occurrences are those from the Cambrian Stage 3 deposits of South China that are c. 520 million years old (Ma). The youngest specimens include those reported here from deposits that are c. 490 Ma. Phosphatocopids were a widespread Cambrian group known to comprise about 60 described species that are identifiable from their bivalved dorsal shield. Briefly, they became a significant component of the euarthropod microbenthos during the late Guzhangian and in the succeeding Furongian and are associated with dysoxic seabed environments. Whilst their soft tissue preservation is generally rare, secondary phosphatization of limbs and other non-biomineralized body tissues is known in specimens from Sweden, Australia, England, China, and Poland. When such soft tissues are preserved, these fossils have proven useful in deciphering relationships between the taxa, and in the broader analysis of the phylogenetic relationships of Phosphatocopida. Reported here is a genus of the first exceptionally preserved phosphatocopid from the late Cambrian (Stage 10, Eoconodontus notchpeakensis conodont biozone) of the USA. Discussed is the likely functionality of its limbs, which suggests a close relationship with the phosphatocopid Cycloton, and an examination of the wider phylogenetic implications of this exceptionally preserved Cambrian crustacean.

About himself, Rich writes:

My current research is looking at the Jurassic warm interval to help develop insight into the behaviour of climate systems under elevated carbon dioxide and temperature. A significant feature of the Mid-Late Jurassic was the presence of large epicontinental seaways such as the Middle-Late Jurassic Sundance Sea of North America. At its greatest extent, the Sundance Sea stretched from Utah to the Arctic Ocean. These large epicontinental seaways are the dominant source for much the information about ancient marine climates and biodiversity. However, these seaways are often decoupled from open-ocean conditions because of variations in water mass, depth, salinity, and stratification and being a loci of anoxia. Using isotopes from calcite fossils such as Belemnites and Gryphaea it is possible to more accurately infer the Jurassic Palaeoclimate; reconstructing how epicontinental seaways interact in terms of ocean circulation, carbon cycling, and climate amelioration.

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