Eubrontes

''Eubrontes'' is the name of fossilised dinosaur footprints dating from the Late Triassic and Early Jurassic. They have been identified from France, Poland, Slovakia, Czech Republic, Italy, Spain, Sweden, Australia (Queensland), US, India, China and Brazil (South).

''Eubrontes'' is the name of the footprints, identified by their shape, and not of the genus or genera that made them, which is as yet unknown but is presumed to be similar to ''Coelophysis'' or ''Dilophosaurus''. They are most famous for their discovery in the Connecticut River Valley of Massachusetts in the early 19th century. They, among other footprints, were the first known non-avian dinosaur tracks to be discovered in North America, though they were initially thought to have been made by large birds.

Discovery and identity

The footprints were first described by Edward Hitchcock, a professor of Amherst College, who thought they were made by a large bird. He originally assigned them to ichnotaxon '' Ornithichnites'' in 1836, then '' Ornithoidichnites'' in 1841, before coining ''Eubrontes'' in 1845. The name means "true thunder," probably referring to the supposed weight of the animal impacting on the ground.

in 1858 Hitchcock still described the tracks as those of "a thick-toed bird," since there was no evidence of tail drag marks. But by the time that Richard Swann Lull began working on the tracks in 1904, they were thought to belong to a dinosaur. Lull originally thought they were from a herbivore, but by 1953 he concluded they were from a carnivorous theropod. Many later authors have agreed with this interpretation, but some have suggested that they are from a prosauropod. Regardless, they are almost certainly saurischian.

A typical ''Eubrontes'' print is from 25–50 cm long, with three toes that terminate in sharp claws. It belongs to a biped that must have been over one metre high at the hip and from 5–6 metres long. In the 1960s Edwin Colbert and others supposed that a large heavy carnivore like '' Teratosaurus'' (then considered to be a dinosaur) made the track, but a possible candidate is ''Dilophosaurus'', a large theropod related to ''Coelophysis'', or a close relative such as ''Podokesaurus''. However no ''Dilophosaurus'' fossil material is associated with ''Eubrontes'' tracks. The tracks may also be from a plateosaurid. In 2016 Molina-Perez and Larramendi based on the 45 cm (1.48 ft) long footprint estimated the size of the animal at 8.4 meters (27.5 ft) and 600 kg (1.323 lbs). Another 60.5 cm (1.98 ft) long footprint belongs to an 8.1 meter (26.6 ft), 1.1 tonne (2.425 lbs) individual, that was very similar to Sinosaurus triassicus.

Another major find occurred at Rocky Hill, Connecticut in 1966. Nearly 600 prints are preserved there in an area now designated Dinosaur State Park.

The paleontologist Robert E. Weems proposed in 2003 that ''Eubrontes'' tracks were not produced by a theropod, but by a sauropodomorph similar to ''Plateosaurus'', excluding ''Dilophosaurus'' as a possible trackmaker. Instead, Weems proposed '' Kayentapus hopii'', another ichnotaxon named by Welles in 1971, as the best match for ''Dilophosaurus''. The attribution to ''Dilophosaurus'' was primarily based on the wide angle between digit impressions three and four shown by these tracks, and the observation that the foot of the holotype specimen shows a similarly splayed-out fourth digit. Also in 2003, paleontologist Emma Rainforth argued that the splay in the holotype foot was merely the result of distortion, and that ''Eubrontes'' would indeed be a good match for ''Dilophosaurus''.
The paleontologist Spencer G. Lucas and colleagues stated in 2006 that virtually universal agreement existed that ''Eubrontes'' tracks were made by a theropod like ''Dilophosaurus'', and that they and other researchers dismissed Weems' claims.

In 2006, Weems defended his 2003 assessment of ''Eubrontes'', and proposed an animal like ''Dilophosaurus'' as the possible trackmaker of numerous ''Kayentapus'' trackways of the Culpeper Quarry in Virginia. Weems suggested rounded impressions associated with some of these trackways to represent hand impressions lacking digit traces, which he interpreted as a trace of quadrupedal movement. Milner and colleagues used the new combination ''Kayentapus soltykovensis'' in 2009, and suggested that ''Dilophosauripus'' may not be distinct from ''Eubrontes'' and ''Kayentapus''. They suggested that the long claw marks that were used to distinguish ''Dilophosauripus'' may be an artifact of dragging. They found that ''Gigandipus'' and ''Anchisauripus'' tracks may likewise also just represent variations of ''Eubrontes''. They pointed out that differences between ichnotaxa may reflect how the trackmaker interacted with the substrate rather than taxonomy. They also found ''Dilophosaurus'' to be a suitable match for a ''Eubrontes'' trackway and resting trace (SGDS 18.T1) from the St. George dinosaur discovery site in the Moenave Formation of Utah, though the dinosaur itself is not known from the formation, which is slightly older than the Kayenta Formation.

Weems stated in 2019 that ''Eubrontes'' tracks do not reflect the gracile feet of ''Dilophosaurus'', and argued they were instead made by the bipedal sauropodomorph ''Anchisaurus''. In a 2024 review of Jurassic tracks, the paleontologist John R. Foster and colleagues stated that few other ichnologists had accepted Weems' sauropodomorph interpretation of ''Eubrontes'', partially because such tracks are abundant in places where no sauropodomorph fossils have been found.

Paleopathology

A trackway attributed to the ichnogenus ''Eubrontes'' had a missing second digit on the right foot. The animal could have either lost the toe due to injury or it was malformed.Molnar, R. E., 2001, Theropod paleopathology: a literature survey: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 337-363.

In popular culture

In early 1970s, a fiberglass cast of an ''Eubrontes giganteus'' footprint was made by Paul E. Olsen, then 14 years old, and his friend Tony Lessa. On June 29, 1972, it was sent by Olsen and Lessa to President Richard Nixon to get his support for registering the Riker Hill Fossil Site in Roseland, New Jersey as a National Natural Landmark.

In 1991, ''Eubrontes'' was named the state fossil of Connecticut.

An ichnospecies of dinosaur footprint from the Early Cretaceous of Gulin County, Sichuan, China was discovered and named as ''Eubrontes nobitai''. The epithet of scientific name commemorate Nobita Nobi, a fictional character in the Doraemon series, for the movies '' Doraemon: Nobita's Dinosaur'' and '' Doraemon: Nobita's New Dinosaur'', which have inspired children's love for dinosaurs.

See also

* List of dinosaur ichnogenera

* Connecticut River Valley trackways
* List of Australian and Antarctic dinosaurs
* ''Grallator''
* ''Anomoepus''
* ''Dilophosaurus''
* Edward Hitchcock

Notes

References

* Colbert, E., ''Dinosaurs'', Hutchinson & Co, 1962
*
* Queensland Dinosaur Trackways home.alphalink.com.au/dannj/larkqury.htm
{{Taxonbar, from=Q5405450
Theropod trace fossils
Fossil trackways
Symbols of Connecticut
Symbols of Massachusetts