Temporal range: Late Triassic
|An artist's illustration of Eodromaeus murphi|
Martinez et al., 2011
| Eodromaeus murphi|
Martinez et al., 2011
Eodromaeus (meaning "dawn runner") is a genus of carnivorous theropod dinosaur from the Late Triassic period. It is a basal theropod which lived during the late Triassic period (middle Carnian age, about 232–229 million years ago) in what is now Argentina. Eodromaeus was named by Ricardo N. Martinez, Paul C. Sereno, Oscar A. Alcober, Carina E. Colombi, Paul R. Renne, Isabel P. Montañez and Brian S. Currie in 2011 and the type species is Eodromaeus murphi. It has been cited by Sereno as resembling a supposed common ancestor to all dinosaurs, the "Eve" of the dinosaurs.
Fossils from Eodromaeus was first discovered in 1991, even though it wasn't understood that it was from a new, previously unknown genus. In 1996, more fossils was found, and it was first believed that it was a new species of Eoraptor. However, as Sereno started to take a closer look at the fossils, he found that it had many skeletal features which were absent in Eoraptor and he understood that it came from a new genus.Eodromaeus is known from the holotype PVSJ 560, a nearly complete articulated skeleton recovered from the Valle de la Luna Member of the top of the Ischigualasto Formation, and the referred materials PVSJ 534, PVSJ 561, PVSJ 562 and PVSJ 877 from Valle de la Luna, La Peña and Cancha de Bochas Members of Ischigualasto. The scientific name Eodromaeus comes from the greek words Eos ("Dawn", "Early") and Dromaeus ("Runner"). The species name murphi is dervied from Jim Murphy, who used to work the area nearby where the fossils were found.
Eodromaeus was a relatively small dinosaur, with a total length of about 1.2 metres (3.9 ft) from nose to tail, and a weight of about 5 kilograms (11 lb). The trunk was long and slender. It is unknown how fast Eodromaeus could run, but it has been suggested to about 30 kilometres per hour (19 mph). The forelimbs were much shorter than the hindlimbs, ending in hands with 5 digits. Digits IV and V (the ring finger and little finger in humans) were very reduced in size.
Eodromaeus is regarded as an early member of theropoda, the group which includes the carnivorous dinosaurs. With the discovery of Eodromaeus, Eoraptor (which also have been regarded as a theropod) has been classified as a member of the sauropodomorpha, the group which includes animals like Apatosaurus. This has been questioned by Bergman and Sues, who have reclaimed Eoraptor as a theropod, like Eodromaeus.