A single specimen of a limacinid thecosomatous pteropod is recorded from Late Cretaceous (late Campanian) rocks of the northeast United States of America. It represents the oldest known occurrence of this gastropod group, predating the next form from the latest Paleocene of Europe and the U.S.A. by some 20 million years.

Heliconoides, Cretaceous, Campanian, first occurrence.
Basteria

CC BY-NC 4.0 NL ("Naamsvermelding-NietCommercieel")

Nederlandse Malacologische Vereniging

Arie W. Jansen, & James L. Goedert. (2016). Notes on the systematics, morphology and biostratigraphy of fossil holoplanktonic Mollusca, 24. First observation of a genuinely Late Mesozoic thecosomatous pteropod. Basteria, 80(1/3), 59–63.