''Gastrochaenolites'' is a

trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...

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 limeston ...

. The aperture of the boring is narrower than the main chamber and may be circular, oval, or dumb-bell shaped. ''Gastrochaenolites'' is most commonly attributed to bioeroding bivalves such as ''

Lithophaga ''Lithophaga'', the date mussels, are a genus of medium-sized marine bivalve molluscs in the family Mytilidae. Some of the earliest fossil ''Lithophaga'' shells have been found in Mesozoic rocks from the Alps and from Vancouver Island.Ludvigsen, ...

'' and ''Gastrochaena''. 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, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

to the Recent. 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

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External links

''Gastrochaenolites'' systematics and diagrams (in German).
{{Taxonbar, from=Q5526817 Boring fossils Ichnotaxa