Museum of Riverside

About Our Allosaurus

The Metropolitan Museum has, in its collections, a cast reproduction of an Allosaurus skeleton purchased in 1978 from an excavation site in central Utah. When we first assembled our website in 1996 the Allosaurus skeleton was described on one of our web pages.  It became one of our most-visited pages even though the skeleton wasn't indigenous to our local area!

We like having visitors to our website so we decided, when rebuilding our website, that our Allosaurus deserved a return engagement!  So here's the story:

Museum revives a Jurassic Dinosaur

In 1927, paleontologists opened the first excavations at what came to be known as the Cleveland-Lloyd Quarry in central Utah. The site’s vast quantity of tangled and disarticulated fossil skeletons received little concerted attention until 1960, when the University of Utah Cooperative Dinosaur Project began work there, under the direction of William Lee Stokes and James Madsen, Jr.  Over the 16 year duration of the project, more than 10,000 bones were recovered representing an array of Jurassic dinosaurs, including Camarasaurus, Stegosaurus, a Camptosaurus, and four types of carnivores, the remains of Allosaurus being more abundant than all the other dinosaur species combined. As part of the project, the cooperating museums were provided with prepared Allosaurus skeletons for display at their respective institutions. In addition to these fossil recreations, the project produced a series of cast reproductions which were subsequently distributed to a wider circle of museums.

It was out of this latter effort that an Allosaurus reproduction came to reside at the Riverside Municipal Museum, purchased in 1978.

While the Cleveland-Lloyd quarry has yet to produce articulated remains of individuals, the quantity of material found there made possible the sorting of skeletal elements into sets of compatible proportions and size. Hundreds of bones for each composite skeleton were reproduced in plaster and plastic resin, designed to be mounted on a simple wrought iron framework and painted to resemble the distinctive charcoal black of the original fossils. At the time of the project, accepted interpretation of dinosaur biology allowed for the tail of an Allosaurus to be in contact with the ground (as we see in living lizards and crocodilians), and thus this feature was used to anchor the distinctive tripodal stance seen in all the Cooperative Project’s fossil skeletons and casts. (More recent restorations of Allosaurus depict the animal with a rigid tail lifted high above the ground, roughly level with the skeleton’s fore portions.)

In restoring its cast of a Cleveland-Lloyd Allosaurus, the Municipal Museum has arrived at a new appreciation for the anatomical wonders of this elegantly structured animal. A mature Allosaurus was a large beast: each thigh bone of this particular skeleton runs about 33 inches in length. Proportionally, with the vertebral column assembled, the total creature approaches 28 feet in overall length. The hind limbs are long and give an impression of great running power. The forelimbs, while shorter, do not have the absurdly vestigial appearance we often expect in meat eating dinosaurs. The shoulder assembly is quite large, the limb bones stout, and the claws quite menacing in size and curvature, almost talon-like. Clearly, Allosaurus was able to grasp and tear at its prey with its forelimbs.

The skull, of course, is the most remarkable of all allosaur features, an arched and airy feature more reminiscent of a Gothic cathedral than the ponderous armament of an alligator or other living reptilian predator. In resin (as opposed to rocky fossil material) the cast skull can give a better sense of the lightness of the bony original. The Allosaurus skull appears to have been so delicately constructed, with so many gracefully connected elements, that it seems to have had an unusual propensity for disarticulating during fossilization. Yet for all its lightness, the animal’s remarkably large head was suited to a massive job: parceling prey up into 100-pound bites. Rather like the jaws of a modern snake, the jaws of Allosaurus could expand laterally around large portions of its victim. A flexible joint midway along the lower jaw allowed the bite to be far larger than otherwise possible. The allosaur’s serrated teeth, while much smaller than those of the Tyrannosaurus rex, were just as capable of tearing free large quantities of flesh.

SOURCES: Madsen, James H., Jr. (1976) Allosaurus fragilis: a revised osteology. Utah Geological & Mineral Survey Bulletin 109 Colbert, Edwin H. (1968) Men and Dinosaurs. Dutton. Paul, Gregory S. (1988) Predatory dinosaurs of the world. Simon & Schuster.

Geology and Earth Sciences

The Museum’s Geological and Earth Sciences holdings consist of approximately 3,500 specimens including Southern California rocks, minerals, and fossils. The rock collections include specimens from the Crestmore Quarry contact metamorphic complex of rare minerals. One of the largest donations to the Collection was assembled by science educator, J. W. Eggleston and came from Riverside City College during the early 1950s. The S. M. Purple Fossil Collection includes type specimens of giant prehistoric California sharks.

Life Sciences

Over 450 zoology specimens depict the wildlife of the Riverside region including: local species of mammals, reptiles, amphibians, bird skins, eggs, and nests.  Approximately 3,000 insect specimens document regional sites of scientific significance (as in a series of voucher insect specimens collected as part of ecological studies of the Deep Canyon facility of the University of California Natural Land and Water Reserve System), in addition to reflecting the role played by UC-Riverside in research into agricultural pest biocontrol. The Collections feature approximately 1,000 dry specimens of molluscs, crustaceans, and other marine invertebrates have been contributed over the years by amateur collectors from the community.

The Clark Herbarium

The Clark Herbarium serves as a reference library to the plant diversity and changes of Southern California.   With almost 10,000 specimens, the Clark Herbarium includes dry botanical mounts, most of which were collected from the Riverside region and surrounding counties by J. C. Roos and other botanists between 1920 and 1960. A small collection of lichens and fungi was assembled during the 1930s by Edmund C. Jaeger, and was later donated to the Museum during his tenure as Curator of Plants. All these materials now represent an important database describing the distribution of native plant species in the southwestern U.S., which is now a vastly altered environmental setting.

The state of California possesses a greater variety of plant species than just about any other comparable geographic area outside of a tropical rainforest. Of this diversity, the Riverside region is endowed with a considerable share, in large part due to the enormous variation in topography and climate that occurs over a relatively small horizontal distance. "As the crow flies", it is possible, in fewer than 10 miles, to travel from below-sea-level saltbush desert to sub-alpine forest communities. As the human population of Southern California continues to boom, some of the Riverside region’s most distinctive plant communities, such as the coastal sage scrub and riparian woodlands, are among the most endangered in the state.
The Museum officially established a Botanical Section in 1954. During the early years, renowned naturalist Edmund C. Jaeger became the museum's Curator of Plants. Facilities for housing a plant collection grew slowly until the late 1970s, when Dr. John C. Roos of Loma Linda offered his personal collection, which included material collected by his father, Alfred Roos, Jaeger, and many others to the Museum. With specimens collected from the 1930s to the 1970s, the Roos collection primarily consists of species from Riverside and surrounding counties in Southern California, plus portions of central California, western Nevada, and northwest Mexico. These Roos specimens became the core Clark Herbarium holdings. The Clark Herbarium is named after Dr. Charles F. and Wilhelmina Husser Clark whose 1949 bequest provided for the establishment of the Botanical Section