Larven-Gehäuse und Gehäuse-Mikrostrukturen von außergewöhnlich gut erhaltenen unterkarbonischen Gastropoden vom Buckhorn-Asphaltlager (Oklahoma, USA)

Crystallographic texture of Late Triassic gastropod nacre: evidence of long-term stability of the mechanism controlling its formation

“…Extraordinary long-term stability of the morphological features of gastropod nacre has already been observed (Batten 1972, Bandel 1991, Bandel et al 2002. The latter authors showed that the nacre of fossil gastropods is composed of many small platelets arranged in columns, thus having the same microstructure as the nacre of living gastropods.…”

“…12.7) is to be accepted. A direct study of the evolution of gastropod nacre is difficult because the oldest known nacreous gastropods come from the Carboniferous (e.g., Bandel et al 2002) and there is only a low number of Late Paleozoic gastropods with a well-documented nacreous layer. Classification of the Paleozoic archaeogastropods at the family rank is still very unstable (compare Knight et al 1960, Wagner 1999, and Bouchet et al 2005.…”

“…Thus all living vetigastropods lacking nacre originated after the Paleozoic time. The phylogenetic position of the extinct Euomphaloidea is uncertain (Bandel & Frýda 1998;Nützel 2002;Frýda et al , 2008a. There is no reason to place them, together with all other extinct Paleozoic archaeogastropod families, within the Vetigastropoda because the latter clade is diagnosed by anatomic features that cannot be examined in extinct groups.…”

Facies and fauna of the Pennsylvanian Buckhorn Asphalt Quarry deposit: a review and new data on an important Palaeozoic fossil Lagerstätte with aragonite preservation

“…In part, this is due to the fact that the most comprehensive studies are unpublished dissertations and theses (e.g., Squires 1973;Cree 1984). These unpublished sources along with other scattered published reports (e.g., Brand 1987;Heaney 1997;Bandel et al 2002) contain important information about the deposit. Therefore, this scattered or not readily available information along with our new data about are mainly Quaternary sediments, the middle part of the state is dominantly Permian, and the eastern part of the state has mostly exposed Carboniferous units (modiWed after http://www.ogs.ou.edu) this fossil occurrence is assembled here to provide a comprehensive interpretation of the deposit.…”

“…Buckhorn mollusc material has been reported in numerous publications to answer speciWc biostratigraphic and palaeobiological questions: e.g., gastropods (Squires 1976;Bandel et al 2002;Nützel and Pan 2005;Nützel et al 2007); bivalves (Heaney 1997;Yancey and Heaney 2000); cephalopods (Smith 1938;Bechtel 1962;Unklesbay 1962;Ristedt 1971;Crick 1982;Chatelain 1984;Gregoire 1988;Blind 1991;Boardman et al 1994;Kulicki et al 2002;and others). Squires (1973) …”