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Acrostemma Cossmann 1889

Year: 2026

Type: article

Abstract: Genus Acrostemma Cossmann, 1889 Type species. Bulla coronata Lamarck, 1804; original designation by Cossmann (1889: 314). Eocene, France. Discussion. This genus is characterized by its strongly elongate pyriform shape with a prominent, raised, convex apical crest delimiting the deep and narrow umbilicus. It was originally known by several species from the Eocene of the Paris Basin (e.g. Cossmann 1889) but persisted at least to the Langhian in the Central Paratethys Sea (Berger 1953) and to the Serravallian in the Proto-Mediterranean Sea (Landau et al. 2013). In the northeastern Atlantic it is documented from the Aquitanian and Burdigalian (Peyrot 1932). At present the genus Acrostemma Cossmann, 1889 is considered a subjective synonym of Cylichna Lovén, 1846 by WoRMS (MolluscaBase eds. 2025c). However, this synonymy is not supported by any published research and the elevated coronate edge of the apical umbilicus is quite different to that of the type species of Cylichna, C. cylindracea (Pennant, 1777).

DOI: 10.5281/zenodo.19166367

Authors: Harzhauser, Mathias, Landau, Bernard M., Malaquias, Manuel António E.

Institutions: Natural History Museum Vienna, Naturalis Biodiversity Center, University of Lisbon, Instituto Dom Luiz, University of Bergen

Topic: Paleontology and Stratigraphy of Fossils

Subfield: Paleontology

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

OpenAlex ID: W7140042464

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