Thomas H. Rich

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Monotremes have left a poor fossil record, and paleontology has been virtually mute during two decades of discussion about molecular clock estimates of the timing of divergence between the platypus and echidna clades. We describe evidence from high-resolution x-ray computed tomography indicating that Teinolophos, an Early Cretaceous fossil from Australia's(More)
The evolution of tribosphenic molars is a key innovation in the history of Mammalia. Tribospheny allows for both shearing and grinding occlusal functions. Marsupials and placentals are advanced tribosphenic mammals (i.e., Theria) that show additional modifications of the tribosphenic dentition including loss of the distal metacristid and development of(More)
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(More)
The Early Cretaceous fauna of Victoria, Australia, provides unique data on the composition of high latitude southern hemisphere dinosaurs. We describe and review theropod dinosaur postcranial remains from the Aptian-Albian Otway and Strzelecki groups, based on at least 37 isolated bones, and more than 90 teeth from the Flat Rocks locality. Several specimens(More)
Analysis of bone microstructure in ornithopod and theropod dinosaurs from Victoria, Australia, documents ontogenetic changes, providing insight into the dinosaurs' successful habitation of Cretaceous Antarctic environments. Woven-fibered bone tissue in the smallest specimens indicates rapid growth rates during early ontogeny. Later ontogeny is marked by(More)
A dentary of the oldest known monotreme, the Early Cretaceous Teinolophos trusleri, has an internal mandibular trough, which in outgroups to mammals houses accessory jaw bones, and probable contact facets for angular, coronoid, and splenial bones. Certain of these accessory bones were detached from the mandible to become middle ear bones in mammals.(More)
less abundant in the mass spectrum of the ozone-fumigated leaf indicating consumption of the antioxidant by the ozone-induced hydroxyl radicals. These preliminary results demonstrate that Py-FIMS is a promising method for revealing multiple damage in plant tissue due to environmental pollution. The next steps are to find relevant key substances in plant(More)
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(More)
A cervical vertebra from the Early Cretaceous of Victoria represents the first Australian spinosaurid theropod dinosaur. This discovery significantly extends the geographical range of spinosaurids, suggesting that the clade obtained a near-global distribution before the onset of Pangaean fragmentation. The combined presence of spinosaurid, neovenatorid,(More)
Dinosaur remains from the Arabian subcontinent are exceedingly rare, and those that have been documented manifest indeterminate affinities. Consequently the discovery of a small, but diagnostic, accumulation of elements from Campanian-Maastrichtian (~ 75 Ma) deposits in northwestern Saudi Arabia is significant because it constitutes the first taxonomically(More)