''Gastrochaenolites'' is a

trace fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...

formed as a clavate (club-shaped) boring in a hard substrate such as a shell, rock or carbonate

hardground Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor (Wilson and Palmer, 1992). A hardground is essentially, then, a lithified seafloor. Ancient hardgrounds are found in limestone ...

. The aperture of the boring is narrower than the main chamber and may be circular, oval, or dumb-bell shaped (Kelly and Bromley, 1984). ''Gastrochaenolites'' is most commonly attributed to bioeroding bivalves such as '' Lithophaga'' and ''Gastrochaena'' (Kleeman, 1980). The fossil ranges from the

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start ...

to the Recent (Taylor and Wilson, 2003; Vinn and Wilson, 2010). The first Lower Jurassic ''Gastrochaenolites'' ichnospecies is ''Gastrochaenolites messisbugi'' Bassi, Posenato, Nebelsick, 2017. This is the first record of boreholes and their producers (mytilid bivalves) in one of the larger bivalves of the globally occurring Lithiotis fauna which is a unique facies in the Lower Jurassic Tethys and Panthalassa.

References

* * * * * * {{cite journal , author = Bassi, D., Braga, J.C., Owada, M., Aguirre, J., Lipps, J.H., Takayanagi, H., Iryu, Y. , year = 2020 , title = Boring bivalve traces in modern reef and deeper water macroid and rhodolith beds , journal = Progress in Earth and Planetary Science , volume = 7 , doi = 10.1186/s40645-020-00356-w, doi-access = free

External links

''Gastrochaenolites'' systematics and diagrams (in German).
Boring fossils