Orodromeus ‭(‬Mountain runner‭)‬

Short Info

Orodromeus ‭(‬Mountain runner‭)‬

Phonetic : Or-o-dro-me-us.

Named By : Jack R.‭ ‬Horner‭ & ‬David B.‭ ‬Weishampel‭ ‬-‭ ‬1988

Diet : Herbivore

Size : Estimated 2 meters long

Type of Dinosaur : Euornithopod

Type Species : D.‭ ‬makelai‭ (‬type‭)‬

Found in : USA,‭ ‬Montana‭ ‬-‭ ‬Two Medicine Formation

When it Lived : Late Cretaceous, 74 million years ago

Orodromeus, which means “Mountain Runner”, is a genus that includes herbivorous orodromine dinosaurs from the Late Cretaceous period of North America. There are two species: O. makelai (possibly Laosaurus) and O. minimus.


Orodromeus skeletonCarpenter, Kenneth, CC BY-SA 4.0, via Wikimedia Commons


Robert Makela discovered the remains of Orodromeus during excavations in Teton County Montana of Egg Mountain’s brooding colony. This was done by Maiasaura, a larger relative. Jack Horner and David B. Weishampel quickly described the type species Orodromeus makelai in 1988. The Greek oros (oros), “mountain”, refers to Egg Mountain, and dromeus (dromeus), “runner”, refers to the cursorial habits. Named in honor of the late Makela.

The MOR 294, holotype of the specimen, was found in a layer from the Two Medicine Formation. It dates back to the Campanian stage about 75 million years ago. It is composed of a partial skull and skeleton. MOR 246 is a clutch of nineteen embryos, some with embryos. PP 22412 is a set with hindlimbs. MOR 331, a partial skull, MOR 248 a skeleton with skull, and MOR 403, an organ case, are the paratypes. Although a thesis unpublished on Orodromeus is available, a complete published description of Orodromeus is not yet available. MOR 246 along with other Egg Mountain eggs are now thought to be part of a troodontid, which could be Stenonychosaurus.

Charles Gilmore, who had described the species Laosaurus minimalus in 1909 using NMC 9438 and pieces of vertebrae from the Allison Formation, Alberta, as the second Orodromeus species, noted it in 1990. It is difficult to identify the specimen because of its fragmentary nature.

Source: Wikipedia