Pterichnus Hitchcock, 1865

DESCRIPTION: Straight to sinuous trackway that consists of two symmetrical horizontal rows of repeated, elongate scratch-like impressions that are turned outward at an angle of 15-20 degrees from axis of trackway. Impressions are similar in size and shape and lack drag marks. External width of trackway is between 4 and 12 mm. Trackways have alternate symmetry and resemble a feather; direction of motion is towards inverted scratches.

BEHAVIOR(S): Repichnia

ENVIRONMENTAL SETTINGS: Shallow marine environments such as intertidal areas

POSSIBLE TRACEMAKERS: Isopod crustaceans

GEOLOGIC RANGE: Triassic-Jurassic; potentially Triassic-recent

ADDITIONAL REFERENCES: Hantzschel (1975); Gaillard (2005)

REMARKS: Description from Gaillard (2005). There are four morphotypes of Pterichnus that include Type 1: trackway with well-defined parallel rows with no scratch pattern; Type 2: holotype described above; Type 3: trackway with scratches lying almost parallel to trackway axis, which are often connected to each other; Type 4: shallow trackway with flat bottom. These morphotypes vary depending on preservation and media consistency; Type 1 was formed under the driest sediment, while Type 4 under the wettest (Gaillard, 2005).