First record of a Hirnantia Fauna from Spain, and its contribution to the Late Ordovician palaeogeography of northern Gondwana

A new occurrence of the Hirantia brachiopod fauna is documented from the Cr iadero Quartzite of Almaden, Ciudad Real Province, Spain. This unit is the regional development of a largely unfossiliferous sandy facies that frequen tly overlies the typical Late Ordovician diamictitic glaciomarine formation s in the Iberian Peninsula and the Armorican Massif. The new occurrence est ablishes palaeontologically the latest Ashgill age of the quartzite, at lea st for its lowest horizons, and adds new data on a fauna that, although wid espread, has been very rarely documented from peri-Gondwanan Europe. The ne w collection contains only Hirnantia sagittifera and Plectothyrella crassic osta chauveli. The subspecific status of the latter and its inclusion withi n Plectothyrella crassicosta is discussed herein, based on the continuous v ariation in rib thickness of several samples of both forms. The extremely l ow diversity and the occurrence of the key form P. c. chauveli, are both ty pical of the Bani Province that developed on the subpolar margins of Gondwa na. This contrasts with other occurrences of the Hirnantia Fauna in peri-Go ndwanan Europe, such as those from Sardinia and the Carnic Alps, which are characteristic of the more temperate Kosov Province.