Fodinichnia (singular fodinichnion) are

trace fossils 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 by deposit feeders as they excavate the sediment in search of food.Allaby A & Allaby M (1999) Oxford Dictionary of Earth Sciences. They tend to have repeated patterns (e.g. '' Chondrites'') or spreites (e.g. '' Rhizocorallium''), the shape reflecting the systematic feeding strategy used by the organism as it scours the sediment. Deposit feeding often results in structures with no overlapping parts, as the deposit feeder optimises its nourishment intake by avoiding going over the same area more than once. This avoidance behavior is called phobotaxis. The shape of fodinichnia can yield evidence of the

depositional environment In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be ...

of the sediment in which they were made. For example, a trace with highly sinuous branches may reflect nutrient-poor conditions where the organism needed to ingest more sediment in order to acquire the same amount of nutriment that a straighter branch in a nutrient-rich environment would.

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See also