A rare find: protoconch in Cretaceous nerineid “gastropod dinosaurs”
Schulbert C, Nützel A, Kollmann H, Kaim A (2019)
Publication Language: English
Publication Type: Conference contribution, Abstract of a poster
Publication year: 2019
Pages Range: 102
Conference Proceedings Title: Abstracts of the 90th Annual Meeting of the Paläontologische Gesellschaft
Event location: München
ISBN: 978-3-946705-07-9
Abstract
Nerineoidea is a very diverse fossil group of mostly high-spired gastropods, some of them quite
large and with complex folds and protrusions in the aperture respectively whorls. The family ranges
from the Jurassic to the end-Cretaceous mass extinction event so that the group can be referred to as
“gastropod dinosaurs”. There are several hundred to a few thousand named species. Despite this high
diversity, only very few protoconchs have been reported because nerineoids occur mostly in shallow
water mixed siliciclastic/calcareous sediments that are prone to strong diagenetic alteration and are thus
not favourable for the preservation of tiny, delicate gastropod protoconchs. We found well-preserved
protoconchs in the nerineids Aptyxiella granulata Münster and A. flexuosa (Sowerby) from Cretaceous
deposits of the Gosau Group at the Pletzach Alm in Austria. It is a smooth heterostrophic larval shell.
The high-spired taxa in question is also well-documented in terms of external shell ornaments and the
fold pattern within whorls. The latter are documented by internal moulds as well a micro-ct scans. The
new find sheds new light on the discussions of the phylogenetic position of Nerineoidea either close
to Tubiferidae (“opisthobranchs”) or Pyramidellidae. The systematic position of nerinid gastropods
(Tubiferidae) is supported by the position of the exhalant opening at the posterior end of the aperture
as a consequence of the shifting of the pallial cavity to the right side. Furthermore, the parietal and
the palatal plaits which obviously had no function in muscle attachment delimit a posterior space proceeding
from early ontogenetic whorls to the penultimate whorl. It is opening to the anterior part of
the whorl in a narrow slit and is considered as equivalent to the pallial caecum of the Heterobranchia.
Besides this morphological distinction, a comparabale diet of these generally large gastropods to that
of modern Pyramidellidae seems unlikely.
Authors with CRIS profile
Involved external institutions
Ludwig-Maximilians-Universität (LMU)
Germany (DE)
Instytut Paleobiologii (Polskiej Akademii Nauk, PAN) / Institute of paleobiology (Polish Academy of Sciences)
Poland (PL)
Naturhistorisches Museum Wien
Austria (AT)
Germany (DE)
Instytut Paleobiologii (Polskiej Akademii Nauk, PAN) / Institute of paleobiology (Polish Academy of Sciences)
Poland (PL)
Naturhistorisches Museum Wien
Austria (AT)
How to cite
APA:
Schulbert, C., Nützel, A., Kollmann, H., & Kaim, A. (2019, September). A rare find: protoconch in Cretaceous nerineid “gastropod dinosaurs”. Poster presentation at 90th Annual Meeting of the Paläontologische Gesellschaft, München, DE.
MLA:
Schulbert, Christian, et al. "A rare find: protoconch in Cretaceous nerineid “gastropod dinosaurs”." Presented at 90th Annual Meeting of the Paläontologische Gesellschaft, München Ed. Paläontologische Gesellschaft, 2019.
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