Tectogonotoechia rivasi n. sp. A new lower Pragian Celtiberian (Spain) Ancystrorhynchoidea rhynchonellid brachiopod

A new lower Pragian Ancystrorhynchoidea rhynchonellid, Tectogonotoechia rivasi n. sp. of the Celtiberian region (Eastern Iberian Chain, EIC, and Eastern Guadarrama, EG) is described and fi gured. The growth of the new species, from the last neanic stage to the senescent one is specially underlined. T. rivasi n. sp. is characterized as the other species of the genus by the occurrence of a pseudoseptum and a pseudoseptalium in the dorsal interior, with a fi ne connectivum forming a roofed over structure covering most part of the latter. Exteriorly, the species is a entirely costate, strongly dorsibiconvex, uniplicate form lacking of marginal spines. T. rivasi n. sp. is fairly abundant in the upper part of the Nogueras Formation in the EIC and in the lower third of the Cercadillo Formation in the EG and it is usually accompanied by a varied macrofauna of brachiopods, bryozoans, solitary corals, tabulates, trilobites, ostracods and others. The biocenose of T. rivasi n. sp. is characterized by the occurrence of abundant incrusting and boring epizoans colonizing mainly the brachiopods, representing different symbiotic interactions and probably a permanent risk for the epizoans to be buried in an unstable soft substrate.