Article: A review of the late Ordovician Foliomena brachiopod fauna with new data from China, Wales, and Poland
L. R. M. Cocks and Rong Jia-Yu
The late Ordovician Foliomena fauna is now known from five palaeocontinents, South China, Avalonia, Baltica, north-west Gondwana, and Laurentia, but has not yet been recorded from the others. New records of the fauna are presented from the Tangtou Formation, South Jiangsu Province, China, and from the Staurocephalus clavifrons Beds in Poland, and illustrated for the first tune from the Crugan Mudstones of North Wales. The occurrences and ages of all known Foliomena faunas are documented and reviewed, and it is concluded that the most typical Foliomena fauna, including true F. folium, occurred from the latest Caradoc (Onnian) beds to the early upper Ashgill (mid-Rawtheyan). Its ecology is discussed, and evaluated as deep-water, but not necessarily ocean-facing, and marginal to continents. Comparable faunas, one including the closely related ribbed Proboscisambon, are identified as occurring in Bohemia, Canada (Perce, Quebec), and Wales (Garth). The taxonomies of Foliomena and the Eoplectodonta genus-group are briefly discussed, with Kozlowskites recognized as a sub-genus of Eoplectodonta and Foliomena confirmed as a strophomenacean.