San Diego Natural History Museum--Your Nature Connection[BRCC San Diego Natural History Museum: Paleontology]
New Fossil Walrus Remains Found at Otay Ranch

October 2001

Field paleontologists from the Museum have been discovering and collecting fantastic new fossil remains of an extinct walrus from a construction site at Otay Ranch in eastern Chula Vista. Grading activities at Otay Ranch have dug deeply into Pliocene-age (approximately 3.5-2.0 million years old) marine sandstones that locally contain well-preserved fossil remains of a wide variety of marine organisms. The fossil walrus remains discovered during October 2001 include an isolated tusk, several isolated limb bones, and a nearly complete skull of Valenictus chulavistensis.

This extinct species of warm water walrus has enlarged canines (tusks) and was about the same size as the extant Arctic Walrus, Odobenus rosmarus. Valenictus is more closely related to Odobenus than any other known fossil walrus and in some ways is more advanced than the living species. Like Odobenus, Valenictus had tusks, however, these are the only teeth possessed by Valenictus. Its palate and lower jaw are completely edentulous (lacking in teeth). Although lacking in teeth, Valenictus had no problem eating with its highly vaulted palate and muscular tongue with which it created a strong oral vacuum for literally sucking clams out of their shells. Modern Odobenus rosmarus feeds in the same manner and, although it retains cheek teeth, it does not use them in feeding.

Photo of Valenictus skull by Tom Demere
Valenictus skull found by Richard Cerutti. (Profile. Scale in centimeters.)

Text and photographs by Dr. Tom Deméré