Tuesday, May 4, 2010


Meaning: "wrinkle tooth"
Species: R. carolinensis, R. manhattanensis (?)
Nominal Author: Emmons 1856
Age: Middle Carnian (Triassic)
Location: Eastern US (North Carolina, possibly New Jersey and Pennsylvania)
Physical Characteristics: Piscivorous phytosaur of 3 to 8 meters in length with a gavial-like long, slender snout. Skull can be identified by slight posterior depression of the supratemporal fenestra and homodont dentition. Nares are positioned at the highest point on the skull.

Rutiodon carolinensis Emmons 1856. A.M.N.H. No. 1 composite skeleton of material collected in North Carolina. From Colbert 1947.

History and Validity
Although it is one of the oldest and most familiar of the phytosaurs, Rutiodon has struggled as a solid, valid taxon. Since Rutiodon was erected in 1856, numerous species have been added to and subtracted from the genus and its validity has been questioned. Emmons name the type species, R. carolinensis, from the Cumnock Formation (Sanford Basin, Newark Supergroup) o North Carolina. Rutiodon manhattanensis was then found in another basin of the Newark Supergroup by Huene (1913) in New Jersey. In 1922, Case added R. crosbiensis from the southwestern US. Another two species from the southwest, R. gregorii and R. adamanensis, were named by Camp (). However, the three southwest species were later found to be members of the genus Leptosuchus and R. manhattanensis is now considered nondiagnostic due to insufficient material (Doyle and Seus 1995). Therefore, the genus can be restricted to R. carolinensis (Long and Murry 1995). The validity of the type specimen itself has been questioned, but was upheld by Hungerbuhler and Sues in 2001 (who also believed it to be valid in the southwestern as well as the eastern US).


So yeah, this is a pretty problematic taxon and since I'm not too familiar with phytosaurs (Rauisuchians are more my style) I did not know to expect so many issues in the literature when I chose Rutiodon as the feature for the week (hence the late post). I think next week I'll step outside of the Triassic to see if I can get a better understood genus.


  1. I have a fossil labeled Rutiodon from Chinle farm, Colorado. According to this article, that would be too far west. Can you shed any light?

  2. Phytosaur taxonomy is pretty complex, with lots of changes concurring over the years. Rutiodon (as it now stands) is indeed only found in the east and there is only a single species in the genus, Rutiodon carolinensis. There are several phytosaurs species that your specimen could belong to, but I'd have to know more about it and/or see a picture to be able to suggest a potential ID.