Horner Study On T. rex Growth

What timing! Jack Horner and Kevin Padian have just published their study on the ages and growth times for 7 Montana T. rexes. This may be the reason that we did not see any Montana fossils in the Erickson study. They studied the bone cortex and determined that they ranged from 15 to 25 years old. They state that they reached maturity by age 20 and lived for about 5 years as adults. They equate the growth pattern to that of the African elephant. So using different specimens and different methods they come up with results very similar to those of Erickson and Makovicky. There are some interesting variations within the sample fossils used. The largest and most robust were not always the oldest ones. (Horner & Padian in Proc. Biol. Sci. 271/p. 1875)

South Dakota Demands Return of T. rex Tinker

In 1998 Ron Frithiof of Texas and friends unearthed the 65 MY old 90% complete skeleton of a young T. rex they named Tinker. It was found on the property of a private landowner. In 2000 they returned to the area to find more bones and signed an agreement with the county to give the County 10% of proceeds from any finds. In 2001 the property was resurveyed and some of it near the Tinker site was found to be county property. They include Tinker under the agreement and sued the finders for the return of the fossil saying that they trespassed and committed fraud. They say that the fossil is valued at $8.5 million. Time will tell what happens. (Rapid City Journal)

Cambrian Evidence for Predatory Behavior

A Cambrian 510 MY old arthropod has been found with the remains of trilobites within its gut structure in South China. The carnivore can not be identified because parts of head and body are missing, but it is similar to Fuxianhuia. It is about 3 inches long and has paired phosphatic nodules along the gut which they interpret as digestive glands. They also detect spherical bacteria in the nodules. The gut is filled with fragments of the eodiscoid trilobite Pagetia. They interpret this fossil as a predator eating live trilobites. They state the following evidence for their theory: the skeletons are fragmentary; they are all in the alimentary canal and not in the surrounding matrix; they are evenly distributed throughout the gut; they are uniform in size; they are all of the same species; and the arthropod was buried quickly. They rule out the following alternatives: coincidental association of the two animals; water currents inserting the trilobites inside the predator; and scavenging on dead trilobites. They rule out scavenging because most scavengers today are non-selective feeders and would be unlikely to have only one animal in its gut. (Zhu et al in Proc. R. Soc. Lond. B 271/p.277)
 

          Karen Nordquist, ESCONI Paleontology Study Group