219-5 The diverse trilobite fauna from the Fezouata Shale biota (Early Ordovician, Morocco)

Session: Paleontology, Diversity, Extinction, Origination (Posters)

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Abstract:

Located in south-eastern Morocco, in the Anti-Atlas region, the Fezouata Shale Biota contains the most diverse association of exceptionally preserved fossils from the Lower Ordovician known to date. Trilobites stand out in terms of their species richness, with an estimate of 21 genera belonging to 14 families reported to date, most of which are early members of major trilobite clades that diversify during the Ordovician and inhabit the high latitude marine ecosystem of West Gondwana. However, since the original regional work carried on by Destombes, the trilobites of the Fezouata Biota have received little attention, and few taxa have been properly studied in terms of their taxonomy and systematic classification. Several of the Fezouata trilobite species lack a formal description, and thus this major fossiliferous site remains drastically neglected in terms of one of its most significant faunal components therefore the true trilobite diversity of the site is unknown. Here we present an overview of the trilobites found in the Fezouata Shale, which illuminate the site’s diversity, including newly discovered species and comparisons with trilobite associations from other West Gondwana basins.

We report seven new species belonging to the genera Prionocheilus, Parabathycheilus, Selenopeltis, Euloma, Tolenataspis, Harpides and Apatokephalus, including a new cheirurid genus with one new species. Some of the new taxa (e.g. Prionocheilus n. sp.; Selenopeltis n. sp.) represent the oldest members of their respective clades. We also provide new exquisitely preserved material from the species Anacheirurus adserai, Bavarilla zemmourensis, Ampyx priscus, Symphysurus ebbestadi, Platypeltoides magrebensis, Dikelokephalina brenchleyi, Megistaspis hammondi and Asaphellus fezouataensis, facilitating a complete overview of the morphology these taxa. 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8094

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