Grallator

Negative footprint of G. cuneatus showing skin impressions

The most famous, and archetypal tracks that conform to the Grallator type are those found on the East Coast of North America, specifically from the Late Triassic to Early Jurassic Newark Supergroup. These footprints were likely made by an unidentified, primitive dinosaur similar to Coelophysis.[2] The Newark Supergroup footprints show digits II, III and IV, but no trace of the shorter digits I and V which would likely have been present in a dinosaur of this stage. The outer two digits would have been stubby and ineffective, not touching the ground during walking or running.[2] Despite losing most of their effectiveness, dinosaur evolution had not yet removed these digits to fully streamline the foot. This is known because rare specimens are found with traces of these outer digits. Digits II, III and IV have 3, 4 and 5 phalanges respectively, giving Grallator a ?-3-4-5-? digital formula.

Although the Newark Supergroup Grallator tracks were made by a bipedal saurischian dinosaur, they can easily be mistaken for those of the late Triassic ichnogenus Atreipus.[4] The trackmaker of Atreipus prints was a quadrupedal ornithischian. The reason for this similarity is a lack of divergence in the foot evolution of the two distinct groups of dinosaurs: ornithischians and saurischians.

Eubrontes (= Grallator) in the Lower Jurassic Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, southwestern Utah.

Fossil tracks can be informative about theropod pathologies but apparently pathological traits may be due to unusual behaviors. Sandstone stratum dating to the Norian in southern Wales preserves tracks of an individual with a deformed digit III attribute to the ichnogenus Anchisauripus. The distal end of the digit was consistently flexed. However, this apparent pathology could be caused by the animal rotating the tip of that digit when lifting the foot.[6]

In January 2021, while walking with his father Richard Wilder, a four-year old Lily Wilder found a 215 to 220-million years old dinosaur footprint at Bendricks Bay in the Vale of Glamorgan, Wales.[7][8][9]

Experts believe the footprint was most likely left by a dinosaur (grallator) that stood about 75 centimeters (29.5 inches) tall and 2.5 meters (about 8 feet) long and walked on its two hind feet.[10][11]

The scientists called the girl's discovery "the finest impression of a 215 million-year-old dinosaur print found in Britain in a decade".[7] Karl-James Langford, an archaeologist from Amgueddfa Cymru – National Museum Wales, called it as the discovery of "international importance."[7][12] Cindy Howells, the curator of the museum, described it as “one of the best-preserved examples from anywhere in the UK” and said it “will really aid palaeontologists to get a better idea about how these early dinosaurs walked.”[9]

• List of dinosaur ichnogenera

• Calvo, Jorge Orlando; Rivera, Cynthia (2018). "Huellas de dinosaurios en la costa oeste del embalse Ezequiel Ramos Mexía y alrededores (Cretácico Superior, Provincia de Neuquén, República Argentina)". Boletín de la Sociedad Geológica Mexicana. 70 (2): 449 ‒ 497. doi:10.18268/BSGM2018v70n2a11.