New Human Skull
Meave Leakey reports on a new human skull that she found in Kenya in 1999 (KNM-WT 40000). It is a new species that is dated volcanically to 3.5 MYA is called Kenyanthropus platyops, flat-faced man from Kenya. This species lived at the same time as the Australopithecine "Lucy" and adds further proof of the bushiness of man’s family tree. The skull is fairly complete and there is also a partial jaw. The sex can not be determined at this point. The cranium size is estimated to be between those of A. afarensis and A. africanus. This specimen shows that a flatter face emerged earlier in evolution than thought. This may be a diet driven adaptive radiation allowing several species to coexist. The species is different from Australopithecus based on its derived face and small molar size. They share a small brain size. The bones were found in a mudstone along the northern edge of a shallow lake. The area was well watered and well vegetated with predominant woodland and forest edge animals present. It will be interesting to see how this new species is integrated into the family tree of man.
Mazon Creek Database
I have been notified that the Illinois State Museum now has a collections database on the web now. I did try to get it this weekend and it wasn’t up yet, but I’m sure it will be there soon. The address is www.museum.state.il.us/exhibits/mazon_creek/. They will have information on species identification, locality, and bibliographic references for each fossil specimen. There will be full color images of most specimens also.
More Chinese Cambrian Fossils
China continues to be the site of fascinating fossil discoveries. This time not in the Mesozoic Liaoning beds of feathered dinosaurs, but near Chengjiang for the Early Cambrian Explosion. They are finding new related beds and new exciting animals that may help tell the story of early animal evolution. They describe one new animal called Cambrotentacus sanwuia (tentacled animal from the Cambrian)which has a calyx on a stalk. A horseshoe shaped ring holding about 30 tentacles that could bring food into its u-shaped digestive tract tops the calyx.
At some of the sites they have found familiar animals like Anomalocaris , Naraoia, Leancholiila, trilobites and brachiopods. But there are also new strange forms that may help tell the story of early evolution. Altogether there are about 10 new localities of the Lower Cambrian formations being explored and probably more to come. These are dated before the Burgess Shale (Middle Cambrian at about 505 MYA) at about 520 MYA. They are near the dates of the Sirius Passet fauna in Greenland and later than a site in Poland. It will be interesting to see how this might change the thinking about the Cambrain Explosion.
Gut Contents of a Tyrannosaurid
A new article by David Varricchio at the Montana Museum of the Rockies tells about the discovery of the stomach contents of a T rex (OTM-200) in the March 2001 issue of the Journal of Paleontology. This is a Daspletosaurus sp. That was found in the Late Cretaceous rocks of Montana in the Two Medicine Formation. This would be the first report of gut contents for a tyrannosaurid. The remains consist of acid-etched vertebrae and part of a dentary from juvenile hadrosaur dinosaurs. The hadrosaurs were abundant in the area at the time and would be a likely food source. The bones exhibit the same kind of corrosion found on present day stomach acid-etched bones. He says that this means that they had digestive systems similar to birds and crocodiles with a two-part system. This would include a first part with enzymes followed by a thick-walled muscular gizzard. This is in agreement with a large Canadian coprolite reported with young hadrosaur bones in it. There are also many reports of dinosaur bones found with teeth marks from tyrannosaurids, although they are usually on the limb bones not the vertebrae. There have also been reports of some gut contents of other dinosaurs, including lizards inside Compsognathus and Sinosauropteryx, a cannibalistic Coelophysis (controversial), and acid-etched bones found with a Baryonyx.
The site contains some bones of the tyrannosaurid and some of the juvenile hadrosaurs along with two teeth from another small theropod (Saurornitholestes), aquatic gastropods and bivalves. The bones may have come to rest in a floodplain pond. The tyrannosaurid remains include several teeth, 30 vertebrae from all regions of the backbone, several ribs and chevrons, and most of the pelvis. They are disarticulated but keep some of the shape of the body. The hadrosaur elements are 4 tail vertebrae and part of the skull and they are found near the pelvic region of the tyrannosaurid. The prey animal was probably 3 meters long. The vertebrae show loss of the thin outer bone layer and even some deeper bone tissue loss. They appear different from similar bones from other hadrosaur beds. The bones of the tyrannosaurid do not show this loss of bone layers. The skull bone (dentary) is from a smaller hadrosaur only about one meter long and has no teeth. The reasons they are believed to be gut contents are 1) they are in a fine grained low energy deposit, 2) they are close to the tyrannosaurid and nowhere else in the site, 3) the hadrosaur bones have different preservation to those of the tyrannosaurid, and 4) the bone loss on the hadrosaur bones matches those with digestive corrosion. Today crocodiles eat with a minimum of chewing and are able to digest even bone completely in their two part stomachs.
The article already has some skeptics who are not sure that it is gut contents. There is not enough of the tyrannosaurids thoracic section present where the gut was. Some wonder why there are bones from the hadrosaurs’ backbone and face there, which would not be the easiest to eat nor the parts with the most meat. I’m sure there will be much more discussion.
JP3 and Jack Horner (Also Scavenger T rex?)
Jurassic Park 3 is in the works and I saw this story line on the web. Paleontologist Sam Neill goes on an aerial tour of the Isla Soma with a wealthy adventurer and his wife (William Macy and Tea Leoni). This is the infamous island where John Hammond creates and breeds magnificent animals. A tragic accident maroons them on the island and they learn the dreadful implications of the raptor intelligence theory first hand. At a recent visit to Central Michigan University Jack, again a consultant on the movie, would not tell much more information. He told the students to go see the movie. When they asked him about T rex as a scavenger he said "the T rex could hunt and probably did, but not primarily, just like lions – the two main reasons for scavenging are a huge nasal cavity just like a turkey vulture, and the femur and tibia are the same size, therefore it could not run." Is Jack softening on his all scavenger theory???
Karen Nordquist, ESCONI Paleontology Study Group
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Last Updated 05/14/01
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