An artist’s rendering is of Balaenoptera bertae, a newly discovered species of baleen whale from a fossil deposit in northern California. (Photo: R.W. Boessenecker / Rhonda J. Miller)

Surfers are not the only ones who find Half Moon Bay, about half-an-hour south of San Francisco, a choice location. Some previous frequenters of that spot, however, were likely there three-to-five million years ago, and were a diverse population of marine mammals that included a walrus with four tusks and a small whale that scientists have discovered to be a newly-identified species.

The massive cache of mammal fossils discovered at the Bay-area surf spot also included a relative of the recently extinct Chinese river dolphin and a porpoise with an unusual jaw. "The mix of marine mammals I ended up uncovering was almost completely different to that found in the North Pacific today, and to anywhere else at that time," said Robert Boessenecker, a Ph.D. candidate in geology at New Zealand's University of Otago, according to Western Digs. Boessenecker's findings, "A New Marine Vertebrate Assemblage from the Late Neogene Purisima Formation in Central California, Part II: Pinnipeds and Cetaceans," were published in the December 2013 issue of the journal Geodiversitas.

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The fossil discovery includes "a diverse collection of 34 marine vertebrate taxa, including eight sharks, two bony fish, three marine birds, and 21 marine mammals," Boessenecker reported in the journal. Other fossils discovered include the walrus, fur seal, the river dolphin, and "four true porpoises, including a bizarre new genus," according to the study. The "aggregate Pliocene marine mammal assemblage from eastern North Pacific shares little in common with the modern fauna and is mostly composed of extinct genera," Boessenecker reported.

The study of the hundreds of fossilized bones and teeth excavated from the Purisima Formation on the northern California coast opens the window on an eclectic community of pre-Ice Age marine mammlas, according Nature World News. One of the fossils discovered was from a never-before-seen species of whale, named Balaenoptera berate, which is about five to six meters long and related to blue whales and fin whales. The mix of primitive species of porpoise and baleen whales were living near relatively modern marine mammals such as fur seals and right whales.The odd mix of marine animals could be attributed to the Bering Strait being closed at the time and the formation of the Isthmus of Panama, which was a new geological feature two million years ago, said Boessenecker. 

"Once the Bering Strait opened and the equatorial Pacific cooled during the Ice Age, modernized marine mammals were able to migrate from other ocean basins into the North Pacific, leading to the mix we see today," Boessenecker said in a statement. Another recent fossil find in California was in the southern part of the state. In that discovery, a rare whale fossil estimated to be 12 million years old was found encased in a boulder on the grounds of the Chadwick School in Palos Verdes.