Taxonomic study of Ordovician (Llanvirn-Caradoc) Radiolaria from the Southern Uplands (Scotland, U.K.)

Over 100 years ago, Hinde (1890a, b) described Radiolaria in thin sections from Ordovician cherts of the Southern Uplands of Scotland and established for the first time the presence of the group in the Early Palaeozoic. Radiolarians from the Southern Uplands have now been successfully extracted by hydrofluoric acid leaching and the systematic palaeontology of some of the yielded morphotypes is discussed herein. The studied fauna come from two outcrops of radiolarites: one at upper Hawkwood Burn and the other north-west of the village of Crawford. Amongst the radiolarians extracted from the latter outcrop, the genera Inanibigutta and Protoceratoikiscum are common. The presence of the species Inanibigutta diffusa (Hinde), Inanibigutta (?) minuta Wang and Inanibigutta sp. cf. I. verrucula (Nazarov) allows the correlation of the Crawford fauna with the Haplentactinia juncta-Inanigutta unica assemblage in Nazarov's (1988) biozonation, of upper Llanvirn (Llandeilian)-Caradoc age, and with the assemblage documented by Wang (1993) in China, of earliest Caradoc age.