A tribosphenic mammal from the Mesozoic of Australia.

A small, well-preserved dentary of a tribosphenic mammal with the most posterior premolar and all three molars in place has been found in Aptian (Early Cretaceous) rocks of southeastern Australia. In most respects, dental and mandibular anatomy of the specimen is similar to that of primitive placental mammals. With the possible exception of a single tooth reported as Eocene in age, terrestrial placentals are otherwise unknown in Australia until the Pliocene. This possible Australian placental is similar in age to Prokennalestes from the late Aptian/early Albian Khoboor Beds of Mongolia, the oldest currently accepted member of the infraclass Placentalia.

Evidence for low temperatures and biologic diversity in cretaceous high latitudes of australia.

A diverse terrestial biota inhabited polar latitudes during the Cretacous, 105 to 130 Ma (million years ago), along what is now the southeast coast of Australia This biota, from rocks in the Otway and Strzelecki groups, cnsisted of more than 150 taxa of vertebrates, invertebrates, and plants. Oxygen isotope ratios in diagenetic calcite suggest that mean annual temperatures were most likely less than 5 degrees C, and rings present in the fossil araucarian-podocarp-ginko woods indicate saonality. Southeastern Austalia, thus, seems to have had a cool, seasonal, nontropical climate. Dinosaurs that have been recovered are up to five species and three genera of hypsilophodontids, all of which were endemic, and three species of theropods. The occurrence of Allosaurus sp. and labyrinthodont amphibians, which had become extinct elsewhere in the Jurassic, indicate that isolation may have allowed extended surival of these taxa in Australia. In that dinosaurs coped with high latitude for at least 65 million years [Valaginian to Albian time in Australia and Campanian to Maastrictian time (80 to 65 Ma) in Alaska] suggests that cold and darkness may not have been prime factors bringing about the extinction of dinosaurs and some other groups at the Cretaceous-Tertiary boundary, unless they were prolonged.

Lancefield swamp and the extinction of the Australian megafauna.

Excavations into the Australian swamp of Lancefield show that a bone bed dated at 26,000 years ago contains perhaps 10,000 giant extinct animals. Associated artifacts suggest that humans were in the area, but the direct cause of death of the animals is, on present evidence, not explicable. Such a recent date for the classic megafauna shows that it was living together with humans for at least 7000 years in southeast Australia. This enduring association argues against a catastrophic and rapid overkill in the Australian Pleistocene.

A five-year study of mortality in a busy ski population.

A 5-year study of a busy ski population in Utah revealed a total at-risk period of approximately 3.5 million skier-days. While the morbidity (fractures, strains, sprains, and occasionally more severe injuries) associated with skiing is well recognized and considered by most physicians concerned to be distributed somewhat unevenly within the various skills of skiing, the authors have identified an exceedingly low mortality among the same population. Six individuals died as a result of injuries directly attributable to skiing. Three of these were considered to be advanced skiers and three were of intermediate skill. In three instances the environment was considered to play a role in the accident. Two of these victims were skiing out of control, one as a result of ice-covered snow and one as a result of speed in combination with a small jump. The third victim was crushed in an avalanche. One accident was completely unexplained, the skier having skied without apparent attempt at checking or change of course into a nonrecreational area. The two remaining skiers of intermediate skill both suffered injuries incident to falling forward with considerable force onto a relatively flat, hard snow surface. Notwithstanding the intense and sometimes prolonged exertion at relatively high altitudes (9,400 to 11,000 ft or 2.9 to 3.3 km), only one skier with a previous history of atherosclerotic heart disease died while skiing. One additional middle-aged skier with similar history died at the conclusion of the day.(ABSTRACT TRUNCATED AT 250 WORDS)