Rafinesquina Hall and Clarke, 1892

Colmenar, Jorge, 2016, Ordovician rafinesquinine brachiopods from peri-Gondwana, Acta Palaeontologica Polonica 61 (2), pp. 293-326 : 311

Genus Rafinesquina Hall and Clarke, 1892

Type species: Leptaena alternata Conrad, 1838 ; Hudson River Group , Caradoc, Cincinnati, Ohio ( USA) .

Subgenus Mesogeina nov.

Etymology: After Mesogeios Thalassa, ancient Greek name for the Mediterranean Sea.

Type species: Leptaena pseudoloricata Barrande, 1848 ; Zahorany and Bohdalec formations, upper middle Berounian–upper Berounian (lower–middle Katian, Ka1–2 stage slices), Upper Ordovician, Bohemia. Species included: Rafinesquina (Mesogeina) pomoides Havlíček, 1971 , Upper Tiouririne Formation, middle Katian (Ka2), Anti-Atlas ( Morocco); R. (Mesogeina) gabianensis sp. nov., lower part of the Gabian Formation, middle–upper Katian (Ka2–4), Montagne Noire; R. (Mesogeina) loredensis sp. nov., lower part of Porto de Santa Anna Formation, middle Katian (Ka2), Portuguese Central Iberian Zone.

Diagnosis.— Rafinesquina with very well marked ventral muscle field, strong ventral muscle bounding ridges and subparallel and plate-like cardinal process lobes, engrossed posteroventrally only in adult specimens.

Remarks. —The species included below displays very similar features with Rafinesquina Hall and Clarke, 1892 , especially in shell profile, outline and ornamentation. However, the internal features of these species are quite different to those of Rafinesquina , as the strong ventral muscle bounding ridges and the subparallel and the plate-like cardinal process lobes are not so thickened posteroventrally as it is typical of the Rafinesquina type species. These differences may warrant the erection of a new taxa. The morphological similarities of the species under discussion, as well as their differences to the rest of the species of Rafinesquina , besides their geographic restriction to the Mediterranean margin of Gondwana, points to a common ancestor with Rafinesquina . However, similarly to subgeneric divison of Kjaerina , the set of distinctive characters warrants erection of a new subgenus Rafinesquina (Mesogeina) .