Alabama's Mighty Meat-Eater
The Alabama Appalachiosaurus is probably the largest and most complete theropod fossil ever found in the Eastern United States. The Alabama specimen, on display at the McWane Science Center in Birmingham, was discovered in 1982 by Dr. David T. King and his wife, Janet Abbott-King, while they were searching for fossils on a recent roadcut in southeastern Montgomery County (King, David T., Jr., et al., "Stratigraphy and Depositional Environments of the Turnipseed Dinosaur Site in the Upper Cretaceous Demopolis Chalk of Montgomery County, Alabama", Journal of the Alabama Academy of Science 59, No. 2 (1988): 34-48). Only the skull, portions of pelvis, forelimbs and lower hindlimbs were recovered in the initial excavation. A subsequent excavation led by the Red Mountain Museum recovered more of the skeleton, such that the remains are about 40 percent complete. It measured in life about 23 ft (7 m) in length, but it was a sub-adult and only about two-thirds of its full adult size at the time of its death.
Painting of the Appalachiosaurus montgomeriensis (courtesy of Todd Marshall)
Originally identified as an unknown species of Albertosaurus, based on comparison with the type specimen at the Royal Tyrrell Museum of Palaeontology in Alberta, Canada, it has more recently been reclassified as belonging to a new genus and species, Appalachiosaurus montgomeriensis (Carr, Thomas D., et al., "A New Genus and Species of Tyrannosauroid from the Late Cretaceous (Middle Campanian) Demopolis Formation of Alabama", Journal of Vertebrate Paleontology 25, No. 1 (2005): 119-143). It was previously believed to have been a juvenile Albertosaurus libratus; however, this species does not appear in the West until much later. Alternatively, the Alabama specimen was thought to represent an adult of one of the smaller early species of Albertosaurus, such as A. olseni. A notable feature of the reconstruction by the McWane Science Center is that Appalachiosaurus has extremely long forelimbs with three digits, unlike most tyrannosaurids.
Albertosaurus libratus and unknown smaller species (possibly A. olseni)
(illustration by Gregory S. Paul)
The fossil is as significant for its mode of preservation as for its singularity: it lies in shallow marine sediments, 20 to 25 miles from the ancient shoreline. Apparently, the carcass became dessicated on land, then was borne out to sea where it drifted with the near shore currents before sinking and being buried in sediment beneath 100 m of water. At some point in its journey, the heavier distal bones fell through the softer tissues enclosing the carcass (a characteristic feature of this mode of taphonomy).
Cretaceous Alabama was a lushly vegetated narrow coastal plain backing onto the Appalachian Mountains (a much more respectable feature in those days). A shallow marine environment covered the lower half of the state, while the northeastern corner was mountainous. The remaining strip of alluvial plain probably became a dinosaur "superhighway" communicating between the coast of the Interior Seaway and that of the Atlantic (based upon the chronologic and geographic distribution of fossil specimens). Despite this apparent paleogeography, no tracks have been discovered on land.
In contrast with the Western States, the East and particularly the Southeast, was a very poor environment geologically for the formation and preservation of fossils. Only about ninety-nine individual dinosaur specimens have been documented in the Eastern US, some twenty-two of these within Alabama (as compared with thousands in the Western States). Within Alabama, only the Cretaceous age dinosaur fossils are accessible; Jurassic and Triassic rocks are buried under as much as 6000 m of rock. Because of high sea levels during the Cretaceous (as much as 850 ft higher than present levels) and the steep slopes of the young Appalachians, the coastal plain was extremely narrow and subject to frequent flooding. Consequently, no fossils are found in ancient terrestrial settings. Moreover, the lithification process is incomplete in much of the Cretaceous strata and the penetration by acidic groundwater destroys unlithified bone material and calcareous replacement.
Famous 1896 painting of Dryptosaurus by Charles Knight
Appalachiosaurus is only the second known tyrannosaurid found in the Cretaceous of Eastern North America (a type considered identical with Albertosaurus, but known locally as Dryptosaurus, is also represented in New Jersey). Fragmentary theropod fossils, probably those of Appalachiosaurus, have been discovered in Alabama and other states. Based upon the fossil record, Tyrannosaurus Rex and many other larger dinosaurs evidently never reached the Eastern regions separated by the Interior Seaway. It is believed that Appalachioosaurus and a few other species crossed into the Eastern portion of North America from Asia and Europe over a land bridge or through relatively shallow seas at a time when the sea levels had receded. A fascinating feature of Eastern dinosaur finds is that they are considerably older than the earliest appearances of corresponding or descendant species in the West (the Alabama specimen is the oldest known in North America at about 79 Mya). Moreover, the population density of the East may have been much lower than in the West.
See-through image of an Albertosaurus at full charge
(illustration by Gregory S. Paul)
Notwithstanding its immense stature relative to man and two ton plus mass, Appalachiosaurus was, by Cretaceous standards, a lightweight. Lithe and graceful, this magnificent hunter would have been very fleet. Gregory S. Paul, author of one of the finest scientific (yet accessible) studies on the subject of dinosaurs, entitled, The Predatory Dinosaurs of the World (Simon & Schuster, 1988), estimates a maximum sprinting speed of 40 mph or so (based on comparative anatomy with present day "theropods" like ostriches). Elephants can move at 20 to 25 mph and do not truly run - its actually a brisk walk; nor do they have the skeletal strength, musculature or stride length of a large theropod. A running speed of 40 mph, then is probably conservative.
John Horner has argued that T-Rex and similar theropods were predominately scavengers. All predators take advantage of the odd available carcass (lions rob leopards and cheetahs, while packs of hyenas rob the lions), however, I agree with Bakker and others that the morphology of tyrannosaurids clearly indicates an animal designed for chasing and overpowering prey, not simply lumbering up and eating whatever may have inadvertantly died. Present day scavengers depend on predators and are never the largest carnivores in an environment. The largest carnivores are invariably predators. Appalachiosaurus also had acute, nearly binocular, vision and excellent olfactory senses.
As they have since the early days of paleontology in the 19th century, personalities, rivalries and academic politics enter into the study of these magnificent creatures. Othniel Marsh and Edward Cope were bitter foes, and the expeditions of these two in the American West from the 1870s to the 1890s are known as the "Bone Wars". A far less vitriolic rivalry exists today among some paleontologists, but has its consequences as well as amusing moments. Aficionados of dinosaurs will doubtless have observed that the paleontologist, named Burke, working for the bad guys in The Lost World - Jurassic Park 2 bears an uncanny resemblance to the unorthodox and controversial paleontologist Robert Bakker, famous for his book, The Dinosaur Heresies. John Horner was the movie consultant. Hmmmm... In the film, Burke gets eaten by a T-Rex and allegedly this was a joke in favor of Horner by director Spielberg, but Bakker is reported to have quipped, "See, I told you T-Rex was a predator!". Horner is surely the more rigorous scientist, but also less daring in his postulations and frankly not well grounded in living zoology (though light years away from those scientists who seriously argue that the pterosaurs couldn't actually fly!). Some of Bakker's ideas are insightful, for instance he posed that dinosaurs had feather 20 years before any evidence was found of such and he is largely responsible for the re-evaluation of dinosaurs as active and fleet animals, yet his unorthodox methods and unmoderated personal expressions inhibit their acceptance. In recent years, the most successful bone hound has been Paul Serrano, who has dramatically altered the landscape of paleontology with his prolific finds in North Africa.
One of the principal reasons for this page is to draw attention to Eastern paleontological specimens, and the Alabama Appalachiosaurus in particular. This specimen deserves a place of honor in a major museum and serious support, but for many years it suffered from neglect in the scientific community largely due to the "human factor" and its obscurity at the small and little known Red Mountain Museum. If it and other Alabama fossil specimens were to gain popular attention (part of the motivation for placing it at the education-oriented McWane Science Center in Birmingham) more efforts might be devoted to uncovering the paleontological history of this region, which lies largely ignored.
Other species of dinosauria in Alabama and the Eastern United States include the large hadrosaur Lophorothon atopus, the small and nimble ceolurosaurid omnivore Ornithomimus, a classic lambeosaurine hadrosaur called Parasauropholus, an ankylosaurid nodosaur (possibly Panaplosaurus or alternatively Nodosaurus) and a sauropod (sometimes regarded as a hadrosaur) known as Hypsibema. Most of the specimens are represented by a single or a few badly abraded bones. Most commonly, dinosaur fossils are discovered in shallow marine concentrates, a form of deposition encountered at the seashore wherein hard parts are concentrated, sorted and abraded by wave action.