Velociraptor, Allosaurus, Tyrannosaurus: some of the
dinosaurs best known to the public are members of the
Theropoda--colloquially called "the carnivorous dinosaurs".
Uniquely among the three major branches of Dinosauria they
retained an obligate bipedal stance despite reaching 9 tons or
more. While best known for their flesh-eating members, several
lineages of theropods actually evolved into omnivores,
insectivores, and even herbivores. Furthermore, as established
in the 1970s, the theropods also include the only surviving
branch of the dinosaurs: the birds.
These species have done more than capture public attention,
however. New studies have revealed hitherto unknown or poorly
understood parts of their biology. Analyses of their mass
distribution demonstrates, for instance, how some groups
(notably the tyrannosaurids) had specializations for agility
even at large body size. Work on estimating bite forces indicate
that some of these have the most forceful bites known in the
history of land animals. Biomechanical study of the sickle claw
of the dromaeosaurid "raptor" focus on its function as an organ
of grasping and piercing. New specimens unveil novel
morphologies (functionally one-toed theropods) and developmental
patterns (species with teeth as juveniles but toothless as
adults). Furthermore, the distribution of feather form and
pattern in theropods on the lineage towards birds show that the
evolution of avian flight was more converse and complex than it
once appeared.
About the Speaker:
Thomas R. Holtz, Jr. is Principal Lecturer in Vertebrate
Paleontology at the Department of Geology, University of Maryland,
College Park. His research focuses on the origin, evolution,
adaptations, and behavior of carnivorous dinosaurs, and especially
of tyrannosauroids (Tyrannosaurus rex and its kin). He received
his Bachelors in Earth & Planetary Geology at Johns Hopkins in
1987 and his Ph.D. from the Department of Geology & Geophysics
at Yale in 1992. He is also a Research Associate of the Department
of Paleobiology of the Smithsonian Institution National Museum of
Natural History and serves on the Scientific Council of Maryland
Academy of Science (which operates the Maryland Science Center
(Baltimore, MD)). In addition to his dinosaur research, Holtz has
been active in scientific outreach. He has been a consultant on
museum exhibits around the world, and on numerous documentaries.
He is the author of the award-winning
Dinosaurs: The Most
Complete, Up-To-Date Encyclopedia for Dinosaur Lovers of All
Ages (Random House). He was co-editor of the 2014 2nd
Edition of
The Complete Dinosaur (Indiana Univ. Press)
and is in the midst of co-editing the 3rd Edition. He received the
2018-2019 Provost’s Excellence in Teaching Award for Professional
Track Faculty.
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