New interpretations of the phylogeny and taxonomy of delthyridoid spiriferids (Brachiopoda, Lower and Middle Devonian)

Abstract

A new phylogeny is introduced for Lower and Middle Devonian delthyridoid spiriferids with plicated fold and sulcus and bifurcating and trifurcating ribs. The new interpretation is based on side-by-side comparison of the type species of the genera with special focus on the micro-ornamentation and the style of ribbing, especially in the sulcus. During the revision of this group the following taxa are proposed: Multispiriferidae fam. nov, Ovetensispirifer novascotianus gen. et sp. nov., Turcispirifer turciae gen. et. sp. nov.; three taxa are described in open nomenclature: gen. nov. A, ?Turcispirifer sp. A, and Ovetensispirifer cf. ovetensium. In the systematic part, each genus is described including its type species of the studied group. Emended diagnoses from family to species level are given. As a consequence of this study, the geographic distribution of the taxa of each evolutionary branch emphasizes the endemicity present during Early Devonian time and its decline at the beginning of the Middle Devonian. However, on the other hand, faunal pathways are shown from Western Europe to Nova Scotia, from North Africa over Turkey to Eastern Asia and to Arctic Canada, and probably from Venezuela to North Africa.