Larger image (11 kb)
Didymoceras was an unusual ammonite which coiled like a spired gastropod. This is a fragment, probably from the body chamber of an adult. I believe that this belongs to the species referred to as Didymoceras cf. archiacianum in the book by N. L. Larson et al. that I referred to on the main Pierre Shale page. This species resembles Didymoceras archiacianum from France but is probably a new species. (Length 10 cm.)
More complete specimens of Didymoceras cf. archiacianum from the "Worldwide Museum of Natural History" can be seen here.
Back to Itano family home page
Back to Fossil home page