Bryozoan fauna from the Lower Devonian (middle Lochkovian) of Sierra de Guadarrama, Spain

Abstract

A bryozoan fauna containing 11 species is described from the Lower Devonian (middle Lochkovian) of Arroyo del Agua, Sierra de Guadarrama, Guadalajara, Spain. One genus containing one species is new: rhabdomesine cryptostomeFehlerpora insolitan. gen. n. sp. Six additional new species are described: three cystoporates:Cystiramus gracilisn. sp.,Fistuliramus guadarramaensisn. sp., andFistuliphragma tenuisn. sp.; and three trepostomes:Eridotrypella hispanican. sp.,Boardmanella dubian. sp., andLeptotrypella inesaen. sp. Four further trepostome species were identified:Leioclema incompositumDuncan, 1939,Minussina spinosoformisAstrova, 1964b,Leptotrypella verisimilisAstrova, 1970, andLeptotrypella vulgataAstrova, 1964b. The association is distributed over three different sedimentary environments. The high-energy one representing accumulation of debris from bryozoan-coral-pelmatozoan thickets contains eight species dominated by erect branched forms (six species). Tabulate corals are present, especially branches which most likely belong toSubcladopora?abnormis(Mironova, 1974). The environment with moderate to low wave influence contains only two bryozoan species, one erect branched and one encrusting. The third setting represents bryozoan thickets in situ situated in deeper water, the most tranquil environment characterized by four bryozoan species, dominated by three erect forms. Fenestrate bryozoans are absent from the two higher energy environments, whereas the bryozoan thickets in deeper water contain rare unidentified fragments of fenestrates. The bryozoan fauna shows distinct relations to the Lower Devonian (Lochkovian) of Ukraine, one species is known from the Middle Devonian of U.S.A.