Hydrodamalis gigas was almost as large as its fossil ancestor and was a marine herbivore, feeding primarily on brown and red algae. The extinct species of Hydrodamalis were cold adapted sirenians related to the still living Dugong of the tropical Indo-Pacific region. View of newly discovered sea cow skull encased in plaster and burlap field jacket. Note that the skull is still partially entombed by sandstone and cobble matrix. The large central opening in the skull is the nasal passage.
Scale is in cm.
View of partially uncovered skull after 4 days of preparation. View is from the right front side and shows the large narial opening and rectangular brain case. The new skull is the most complete and best preserved specimen of Hydrodamalis cuestae known and was discovered in Pliocene-age marine sandstones of the San Diego Formation as exposed at Otay Ranch. Otay Ranch is being developed by the Otay Ranch Company as a planned community. The fossil was discovered as graders were constructing the Village 1 West phase at Otay Ranch.