Feathered T. rex Ancestor Found – Dilong

“Emperor dragon” is the meaning of the name of this exciting new Liaoning discovery from China. Dilong paradoxus got its species name because of the strangeness of finding feathers on such a ferocious predator. It is dated to 130 MYA and there are 4 specimens, including an almost complete skull. The estimated adult length is 1.6 m (5.25 feet). It has D-shaped premaxillary teeth, fused nasals even in juveniles, small but well-defined sagittal crest, 3 fingered hand, large pubic boot, and non-arctometatarsalian foot. The protofeathers found around the tail and jaw are single flexible shafts rather than the feathers we know today. It may have lost these protofeathers as it matured much as the elephant loses its hair as it ages. This again suggests that feathers evolved in dinosaurs long before birds and that it was probably for insulation when they were young.

Did T. rex Chew??

A new report from the University of Arkansas concludes that tyrannosaurids were chewers not slash and swallowers. Their study began as they tried to answer the predator vs scavenger argument. They assumed that the dinosaurs did not chew their food like modern reptiles. They studied the teeth of modern caimans, iguanas and Komodo dragons and found no microscopic wear facets on their teeth. At the Royal Tyrrell they found wear facets on the teeth of T. rex fossils. They were scratches all running in the same direction which they believe shows that they did indeed do some food processing in the mouth before swallowing. These kinds of marks are common on the teeth of mammals which do a lot of food processing in their mouths. They plan to study the teeth of other dinosaurs to see if they are different. This may indicate that the T. rex had some specialized eating technique for a theropod. The article is being published and I will be interested in hearing the reactions. Actually that would explain why the bones found in the Alberta coprolite were broken into small pieces.

New Long Necked Marine Reptile – Dinocephalosaurus

Olivier Rieppel of the Field Museum is coauthor on this recent paper reporting on new Chinese Triassic fossil information for this amazing creature that lived 230 MYA. It was named Dinocephalosaurus orientalis (terrible headed lizard from the Orient) previously based on a lone skull. This animal resembles the mysterious Tanystropheus but instead of getting its neck length from elongation of the neck vertebrae, it has more neck vertebrae (25 instead of the 12 in Tanystropheus). It also has long delicate vertical ribs to help it stretch when taking in prey in water. They had relatively short and broad limbs with some bones remaining unossified. They believe that the body would remain low in murky water with the small head on the long neck reaching into the shallows after unsuspecting fish. It had needlelike sharp teeth for capturing slippery fish and squid. With the ribs extended would have caused suction to bring in the prey in water. The water could then be expelled with the teeth holding in the prey. The body was about 3.3 feet long with a neck measuring 5.6 feet. This is a fully marine animal related to another reptile – protorosaurs.

Psittacosaurus Adult & 34 Juveniles Found

In Liaoning China yet another exciting fossil has been found. David Varricchio of Montana was among the discoverers of the group found in a depression thought to be a nest. The adult male or female is about 2.5 feet (75 cm) long and all the youngsters are all about 8 inches (20 cm) long indicating they are all from a single brood. But it is hard to believe that they were all born by one adult. This may indicate communal living, with adults taking turns watching over the young. The young are all surrounding the adult in a crouching position leading the authors to suggest they may have died when a tunnel collapsed on them or when flood waters inundated them. This site offers many implications about dinosaur behavior. Psittacosaurs may have lived in groups with the adults watching over them or feeding them. They are not sure that it is a nest yet. The photo below is from the article with the adult on the left. Note that the youngster on the lower right corner appears to be draped over a structure.

Permian Mass Extinction Redated

Important geological dates are important for information about species and the pace of evolution. One of the best methods being used is the decay of Uranium isotopes to lead but can be a problem because of damage to one of the uranium minerals called zircons. Now a new method has been developed that pretreats these zircons to eliminate the damaged parts. The date they worked on was the well studied Permian Extinction at the Permian/Triassic boundary. This has been set at 251.4 MYA plus or minus 0.3 MY. This new technique places the date at 252.6 MYA plus or minus 0.2 MY at two different localities. This puts it at the same date as the Siberian Traps. Unfortunately much of these dating techniques have been done secretly without much sharing and they hope to correct this and increase cooperation in the future.

Homo erectus Brain Growth Study

The skull of a 1.8 MY old Homo erectus child from Java (Mojokerto) has been studied by computer tomography. They find that it is more like that of apes than modern humans. The child was dated at about 1 year old at death and its cranial capacity was about 72-84% that of an average adult H. erectus. This implies major differences between the development of cognitive abilities between H. erectus and modern humans. The fetal pattern of brain growth and long period of growth are features that must have developed in the common ancestor of Homo sapiens and Homo neanderthalensis.

 

          Karen Nordquist, ESCONI Paleontology Study Group