''Haplotichnus'' 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 ...

of invertebrate

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, ...

that was erected by S.A. Miller in 1889. Buatois et al. (1998) proposed that ''Haplotichnus'' should be synonymized with ''

Gordia ''Gordia'' is an ichnofossil 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 fos ...

'' because both exhibit a looping course with self-crossing. Other researchers, such as Wang et al. (2009), have maintained the distinction between the two ichnogenera because ''Haplotichnus'' has sharp bends, whereas those of ''Gordia'' are not sharp. Most recently, Getty and Bush (2016) synonymized ''Haplotichnus'' with ''

Treptichnus ''Treptichnus'' (formerly named ''Phycodes'', ''Manykodes'' by J. Dzik, and also known as ''Trichophycus''See e.gfossiilid.info: paleodiversity in Baltoscandia: Trichophycus pedum/ref>) is the preserved burrow of an animal. As such, it is regar ...

'' due to the presence of bifurcating projections at the bends. Other features, such as the looping course of the trace, thought to distinguish ''Haplotichnus'' from ''Treptichnus'', are actually seen in one of the syntypes of ''Treptichnus'', further supporting Getty and Bush's (2016) synonymy.

References

Trace fossils Invertebrate paleozoology {{trace-fossil-stub