The brachiopod faunas from the Fezouata Shale (Lower Ordovician; Tremadocian–Floian) of the Zagora area, Anti-Atlas, Morocco: evidence for a biodiversity hub in Gondwana

Since the early 2000s, the discovery of fossils and their collection from the Fezouata Shale has accelerated; this has enabled us to understand the faunas more thoroughly. The brachiopod fauna has not been investigated for the past 50 years, and we present here the results of our recent studies. The material represents about 350 samples, in which 30 species were identified, assigned to 23 genera. Among these, one new genus (Tinzoulinorthis) and four new species (Wosekella maghribi, Rafanoglossa inversa, Orbithele tazagurta, Lacunites punctum) are erected; one taxon is recognised at family level. The fauna described from the upper Tremadocian horizons is more diverse than those in the Floian. The former is characterised by a high γ-diversity, although at the horizon level the α-diversity is low to medium. This fauna is typical of high-energy, shallow-water, unstable environmental conditions preventing long-lived communities to develop climax communities and indicating that the succession of opportunists were regularly smothered in-situ and killed by storm deposits. Multivariate analyses of the faunas indicate that the Tremadocian fauna, characterised by many endemic taxa, shows closer affinities with faunas from peri-Gondwanan terranes, in particular Bohemia. The Tremadocian Fezouata fauna is very rich in taxon first occurrences, which coupled with high γ-diversity, suggest it may have been a diversity hub. On the other hand, the Floian Fezouata fauna shows stronger connections with Bohemia and the Montagne Noire albeit also links with the South Urals and Baltica reflecting the changing Early Ordovician palaeogeography.

Methods
Data compiled from various bibliographical sources. References to these sources are indicated in uploaded files.