''Tremichnus'' is an

ichnogenus An ichnotaxon (plural ichnotaxa) is "a taxon based on the fossilized work of an organism", i.e. the non-human equivalent of an artifact. ''Ichnotaxa'' comes from the Greek ίχνος, ''ichnos'' meaning ''track'' and ταξις, ''taxis'' meaning ...

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, ...

. It is an embedment structure (i.e.

bioclaustration Bioclaustration is kind of interaction when one organism In biology, an organism () is any life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxono ...

) formed by an organism that inhibited growth of the crinoid host stereom. The most common endobiotic symbiont in Paleozoic crinoids is ''Tremichnus'' (Brett 1978, 1985)

References

* Brett C.E. 1978. Host-specific pit-forming epizoans on Silurian crinoids. Lethaia, 11, 217-232. * Brett C.E. 1985. ''Tremichnus'': a new ichnogenus of circular-parabolic pits in fossil echinoderms. Journal of Paleontology, 59, 625-635. *{{cite journal , doi = 10.4267/2042/57951 , title = ''Tremichnus'' in crinoid pluricolumnals from the Silurian of western Estonia (Baltica) , year = 2015 , author = Vinn, O. , author2 = Wilson, M.A. , author3 = Auscih, W.I. , author4 = Toom, U. , journal =

Carnets de Géologie ''Carnets Geol.'' (previously ''Carnets de Géologie'' or ''Carnets de Géologie - Notebooks on Geology'') is an electronic journal that publishes in the field of geosciences, and particularly paleontology, stratigraphy, and sedimentology. The ope ...

, volume = 15 , issue = 17 , pages = 239–243 , url = http://paleopolis.rediris.es/cg/1517/index.html , accessdate = 2015-12-04, doi-access = free Trace fossils