Arenicolites

Arenicolites is a U-shaped ichnotaxon (trace fossil)^[1] dating from Ediacaran times onwards in South Australia. The trace shown by this fossil, is a pair of closely spaced circles on a bedding plane. In vertical section the traces are U- or J-shaped. They appear to be burrows made by a kind of worm.^[2]

Trace fossils of Arenicolites in the bedding plane. Trace appears as pairs of circles. Scale bar=2 cm.

Arenicolites in vertical plane. The rock is cut with a rock saw with two oblique cuts. Scale bar = 1 cm.

References

1. Gevers, T.W.; Frakes, L.A.; Edwards, L.N.; Marzolf, J.E. (1971). "Trace Fossils in the Lower Beacon Sediments (Devonian), Darwin Mountains, Southern Victoria Land, Antarctica". Journal of Paleontology. 45 (1): 81–94. JSTOR 1302754.
2. Oji, Tatsuo; Dornbos, Stephen Q.; Yada, Keigo; Hasegawa, Hitoshi; Gonchigdorj, Sersmaa; Mochizuki, Takafumi; Takayanagi, Hideko; Iryu, Yasufumi (28 February 2018). "Penetrative trace fossils from the late Ediacaran of Mongolia: early onset of the agronomic revolution". Royal Society Open Science. 5 (2): 172250. Bibcode:2018RSOS....572250O. doi:10.1098/rsos.172250. PMC 5830798. PMID 29515908.