| Abstrakt: |
The Refrath Formation in the Bergisches Land, Germany, is an important stratigraphic unit for the study of Frasnian brachiopods. Nevertheless, few studies have been undertaken concerning its spiriferide and spiriferinide brachiopods (Cyrtospiriferidae, Verneuiliidae and Cyrtinidae). In this paper, three species representing, respectively, the above families, Cyrtospirifer cuspidatus (d'Archiac and de Verneuil, 1842), Verneuilia cheiropteryx (d'Archiac and de Verneuil, 1842), and Cyrtina bouchardi Brice, 1988, are described from this region for the first time. The first serial transverse sections of Verneuilia cheiropteryx show that the species has well-developed dental plates, contrary to previous consensus; it lacks true crural plates, which is different from typical members of the Ambocoelioidea George, 1931. The presence of this species in the Refrath Fm. demonstrates that it is a Frasnian brachiopod, rather than of Middle Devonian (Givetian) age, as previously considered. The ventral median septum of Cyrtina bouchardi supports and penetrates into the deep spondylium, becoming trifurcate anteriorly. Cyrtospirifer cuspidatus is internally characterized by a well-developed ctenophoridium (cardinal process) and a pair of rudimentary crural plates (crural bases) in the dorsal valve and a deeply sunk delthyrial plate and a pair of divergent dental plates (becoming parallel anteriorly) in the ventral valve. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink