Lower Devonian meristelloids of the Cantabrian Mountains (N Spain).

Abstract

Meristelloids (Superfamily Meristelloidea Waagen, 1883) are relatively diverse, Ordovician to Carboniferous articulate brachiopods. The meristelloid shell is commonly smooth and the brachial system is composed by spiralia and a more or less complex jugum. Specialists have paid scarce attention to Spanish Devonian meristelloids. This has probably been due both to the poor external ornamentation and to the complex internal structure. The smooth shell involves usually homeomorphies both among different meristelloid taxa and between them and another separate groups (i.e. the terebratulids). In turn, the internal complexity calls for very extended and careful serial sections studies to reconstruct the brachial apparatus that take very long time. Several Cantabrian Mountains (N Spain) Lower Devonian meristelloid taxa are described and figured herein. Saberaia n.gen. is only composed by its type-species S. truyolsae n.sp., an external homeomorph of the terebratulid Terebratula Bordini Verneuil, in Prado & Verneuil, 1850. Meristella esbelta n.sp. and Camarium collensis n.sp. are the first known species of both genera in Spain. Triathyris mucronata (Verneuil, 1850) is the type species (by posterior designation due to Le Maître, 1954) of Triathyris. The taxonomic history of Triathyris is analyzed. T. mucronata is redescribed from abundant topotypical material and numerous serial sections that show a typical meristelline brachidium.