The diverse radiodont fauna from the Marjum Formation of Utah, USA (Cambrian: Drumian)
| Autor: | Allison C. Daley, Enrico Bonino, Stephen Pates, Rudy Lerosey-Aubril, Carlo Kier, Javier Ortega-Hernández |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Hurdiidae
010506 paleontology Pahvantia Range (biology) Fauna Zoology Panarthropoda 010502 geochemistry & geophysics 01 natural sciences General Biochemistry Genetics and Molecular Biology Peytoia Genus Pelagic lifestyle Caryosyntrips 0105 earth and related environmental sciences Taxonomy Appendage biology General Neuroscience Exceptional preservation Paleontology General Medicine biology.organism_classification Miaolingian Taxon General Agricultural and Biological Sciences Hurdia Buccaspinea |
| Zdroj: | PeerJ PeerJ, vol. 9, pp. e10509 |
| ISSN: | 2167-8359 |
| Popis: | Radiodonts have long been known from Cambrian deposits preserving non-biomineralizing organisms. In Utah, the presence of these panarthropods in the Spence and Wheeler (House Range and Drum Mountains) biotas is now well-documented. Conversely, radiodont occurrences in the Marjum Formation have remained scarce. Despite the large amount of work undertaken on its diverse fauna, only one radiodont (Peytoia) has been reported from the Marjum Biota. In this contribution we quadruple the known radiodont diversity of the Marjum fauna, with the description of the youngest members of two genera,CaryosyntripsandPahvantia, and that of a new taxonBuccaspinea cooperigen. et sp. nov. This new taxon can be identified from its large oral cone bearing robust hooked teeth with one, two, or three cusps, and by the unique endite morphology and organisation of its frontal appendages. Appendages of at least 12 podomeres bear six recurved plate-like endites proximal to up to four spiniform distal endites.Pahvantia hastataspecimens from the Marjum Formation are particularly large, but otherwise morphologically indistinguishable from the carapace elements of this species found in the Wheeler Formation. One of the two newCaryosyntripsspecimens can be confidently assigned toC. camurus. The other bears the largest spines relative to appendage length recorded for this genus, and possesses endites of variable size and unequal spacing, making its taxonomic assignment uncertain.Caryosyntrips, Pahvantia, andPeytoiaare all known from the underlying Wheeler Formation, whereas isolated appendages from the Spence Shale and the Wheeler Formation, previously assigned toHurdia, are tentatively reidentified asBuccaspinea. Notably, none of these four genera occurs in the overlying Weeks Formation, providing supporting evidence of a faunal restructuring around the Drumian-Guzhangian boundary. The description of three additional nektonic taxa from the Marjum Formation further documents the higher relative proportion of free-swimming species in this biota compared to those of the Wheeler and Weeks Lagerstätten. This could be related to a moderate deepening of the basin and/or changing regional ocean circulation at this time. |
| Databáze: | OpenAIRE |
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