[N] 2006 First occurences of Deinosuchus in Mexico
Westgate, J., Brown, R., Pittman, J., Cope, D. & Kalb, J. (2006) First occurences of Deinosuchus in Mexico. JVP 26(3) Abstracts pp. 138
Remains of Deinosuchus have been found in Chihuahua, MX. Near Ojinaga, the Late Cretaceous San Carlos Formation has yielded a large dermal scute from Deinosuchus sp. The underlying, uppermost Ojinaga Formation bears earliest Campanian open marine ammonites and oysters including Submortoniceras tequesquitense, Placenticeras planum, Eutrephoceras dekayi alcesense, Baculites sp. and Exogyra poderosa erraticostata. Paralic strata in the overlying San Carlos Formation are early Campanian and include Flemingostrea sp. oysters, Baculites aff. B. taylorensis ammonites, and Hardouinia florealis echinoids. T
he San Carlos Formation Deinosuchus sp. is similar in age to D. rugosus specimens reported from the southeastern U. S. (Schwimmer, 2002). Near Los Altares, several Deinosuchus teeth were collected from the paralic Aguja Formation. These specimens are correlative with late Campanian D. riograndensis specimens reported from the Aguja Fm. in Big Bend National Park and are referred to that species.
Deinosuchus is also known from late Campanian strata in Montana and Wyoming. Schwimmer (2002) suggested that all Deinosuchus specimens may be conspecific, and if so, should be referred to D. rugosus. If San Carlos Fm. Deinosuchus are proven to be significantly larger than the southeastern U. S. D. rugosus population, then two species of Deinosuchus may have lived during the early Campanian. However, size differences might also reflect clinal variation in a single species.