Wednesday, February 17, 2010
Scientists have spent the last year deciphering clues from mammoth and gray whale fossils found a year ago in downtown San Diego.
Scientists have spent the last year deciphering clues from mammoth and gray whale fossils found in downtown San Diego.
The fossils were unearthed by San Diego Natural History Museum paleontologists and construction workers during excavation of a building site in February 2009 in the East Village area of downtown San Diego.
Parts of a Southern mammoth were found -- skull with tusks, lower jaw, molar teeth, vertebrae and limb bones; and parts of a gray whale, including an eight-foot section of jaw.
Those are among the fossil remains researchers have been analyzing for clues about climate, evolution and the ecology of the region.
Dr. Thomas Deméré, Curator of Paleontology for the Natural History Museum, said the fossils are an important find for both scientific and educational reasons.
"We know that the time the mammoth was living here, it was a period of warming, not unlike the period of global warming that we're living in today," said Deméré. "And this was a coastal animal, so if you go back in time 300,000 years, there were mammoths walking around here."
Deméré said when the mammoth roamed San Diego it was during a time of high sea level.
He says the mammoth survived three cycles of warming and cooling.
Deméré said the fossil remains may provide answers about the regional climate, but more research is needed.
Deméré said he expected the gray whale fossils would be different than the species that swim the oceans today.
"I had suspected that we might find some anatomical differences that would suggest it (the fossil) was a different species of gray whale," said Deméré. "But every part of the animal we found suggests that it's the same as the living species, suggesting that 500,000 years ago modern gray whales had evolved."
He said other sedimentary layers discovered at the construction site produced fossil remains of land mammals (rabbit, rodent and horse), marine vertebrates (shark, ray and bony fish), and marine invertebrates (oysters, clams, scallops and snails).
Deméré said one of the problems researchers are dealing with is not having precise age-dating for the sedimentary layers in downtown San Diego.
"We can look at it and make a hypothesis about what time period these animals lived in based on the fact that we have cycles of sea level high and low recorded in the sediments in the downtown area and we can correlate these with known periods of global warming and cooling over the last 500,000 years," said Deméré. "But we really need some more precise laboratory-based analysis on the age of these deposits."
He said Southern California and San Diego County have some rich fossil deposits and he would not be surprised if more fossils are found in the future.