Revisiting the productide (Productidina, Strophalosiidina) brachiopod fauna from upper Visean (Mississippian) reefs in Belgium and UK: systematics, palaeoecology and evolutionary implications

The Asbian (upper Visean, Mississippian) reefs of North Yorkshire, Derbyshire (UK) and Visé (Belgium) host rich brachiopod faunas studied since the 19th century. This paper revises the productide brachiopods, which dominate the benthic assemblages in both abundance and diversity. Productidines and strophalosiidines inhabiting the reef framework show attachment cicatrices and clasping or creeping spines used for cementation to hard substrates. Other productidines living on soft, muddy substrates of the reef bank and flank facies display semi-infaunal habits and specialized trail morphologies-such as cinctures, gutters, flanges and tubiform terminations-that likely enhanced internal water flow and reduced sediment ingress, representing adaptations to the highly competitive reef environment. Comparable morphological traits are known in productides from Pennsylvanian reefs in Spain and Arctic Canada, and from Middle Permian reefs in North America, whereas Carboniferous and Permian reefs in China are mostly devoid of reef specialized productides until the Changhsingian. We describe a new genus, Mosaproductus n. gen. (with M. arcuarius as type species), and three new species: Mosaproductus cocksi n. sp., Ovatia burrowi n. sp., and Ovatia tubiformis n. sp., providing a revised assessment of the long-studied Visean brachiopod faunas of the UK and Belgium. Moreover, Undaria erminea is revised and the enigmatic Productus tortilis is tentatively reassigned to Undaria .