By Duane E. Furman
This week’s news is from Niranjala Kottachchi, Fresno State University on-site paleontologist for the Fairmead Fossil Site:
The Fairmead Fossil Site introduces two new fossil finds.
Located approximately 12 miles north of Madera, the Fairmeaad dig, which operates in conjunction with the Madera County Landfill, has produced a treasure trove of Ice Age fossils dating back to the Middle Pleistocence Epoch (750,000-500,000 years ago). Since its discovery in May 1993, at least three dozen species of vertebrates have been discovered. Fossil finds with such high diversity are particularly rare for this time period and thus makes this site the largest in the San Joaquin Valley and one of the largest along the west coast of North America. A complete list of species found at the site has been published in a previous article.
Generally, finds such as horse, camel, mammoth, and large ground sloth are the most common among the species found at Fairmead, so when fossils from rarer animals are found, it is something to get excited about. Over the past two months, during fossil preparation and cataloguing, a fossil fish vertebra and sabertooth cat skull were discovered. The fossil fish vertebra is an example of a microvertebrate.
Microvertebrates are recovered from sediments screened through mesh screens of varying size, ridding finer sediment and leaving behind any larger fragments such as coarse sands and pebbles or shells, bones, and teeth of smaller animals. Often times, microvertebrates require magnification in order to be visible and identified. What is exciting about the fish find is that it is our first fossil fish species ever found from the site.
Although collected from screened sediment back in 2001, it had yet to be identified. The specimen was sent to Dr. Ken Gobalet, a quaternary fish specialist at the Department of Biology at CSU-Bakersfield, who identified it as Archoplites interruptus or Sacramento perch, which still exists in California today. The Sacramento perch is actually a sunfish native to the Sacramento, San Joaquin , Pajaro and Salinas river areas in California as well as other parts of western North America. Reaching as big as 24 inches in length, the Sacramento perch prefers a habitat in sluggish, vegetated waters such as lakes.
Another nice surprise came along during the removal of one of our plaster jackets from 2004. A plaster jacket is composed by mixing burlap with plaster and water which is then used to encase a large or fragile bone to facilitate its removal from the ground. It is very similar to a cast put on a broken bone. As the overlying sediment was slowly being removed from the jacket, a partial skull of a sabertooth cat was unveiled.
According to Dr. Robert Dundas of Fresno State, the specimen appears to be from Smilodon, but the species is yet to be determined, as much cleaning and preparation is required. The Fairmead Site has produced fossils of the species Smilodon fatalis in the past but the back of the skull on the new find is different from S. fatalis.
Dr. Dundas believes it could be Smilodon gracilis or an entirely new species. Although the long canines (up to 7 inches in length) for which the sabertooth cat is famous are both broken, all six of its incisors are present. The skull is incomplete and appears to have undergone severe breakage prior to being buried in the sediment, possibly as the result of trampling by larger animals.
We are very excited to share these findings with the public and will continue to make our discoveries known as further identifications are made. Until then, our list of species continues to grow, making us more aware of just how rich and unique the Fairmead Landfill is to our valley.
Cooperation between the Paleontology Foundation and the County of Madera is resulting in steady progress toward completing and making accessible the Discovery Center. Next steps in the process, now that the site is cleared and the ground breaking ceremony held, are to coordinate the activities and agencies involved in establishing the main building, the watering hole with appropriate plant and animal life, rest rooms, prep. lab., walkways, and security housing on the four acres of the site.
We have also ordered exciting and appropriate skeletal models of some of the creatures who once lived at the site, and are planning state of the art exhibits that will ultimately include a historical time line and the geology of the area.