|
In 1986 scientist discovered on James Ross Island off the coast of the Antarctic peninsula a Late Cretaceous ankylosaur (Olivero et al. 1986), from the Gamma Member of the Santa Marta Formation. This Campanian (Late Cretaceous) marine unit also contains gastropods, bivalves, ammonites and plesiosaurs (marine reptiles). The one incomplete specimen of a probable nodosaurid ankylosaur collected includes skull and other skeletal fragments and armour plates.Three years later on nearby Vega Island the British Antarctic Survey (Hooker et al. 1991) discovered the remains of a Late Cretaceous hypsilophodont, that was collected from a marine deep shelf silty mudstone in the Late Cretaceous Lopez de Bertodano Formation on Vega Island. The specimen includes disarticulated elements of the skull, cervical, dorsal and sacral vertebrae, portions of both pectoral girdles and humeri, and parts of the pelvis (ilium and ischium) (Hooker et al. 1991). The length of the animal, estimated to be 4-5 meters, makes it one of the largest of the hypsilophodonts (normal size range 2-3 meters). Preliminary investigations indicate that while this animal shows features consistent with other hypsilophodonts, it also has some unique features, particularly in the dentition. The humeri and pelvis have some characteristics similar to Dryosaurus and Valdosaurus.Untill now these are the only Cretacous dinosaur known from Antarctica. During an expedition that took place in 1990-91 scientist unearthed on Mt. Kirkpatrick a Jurassic locality in the Transantarctic Mountains, approximately 650 km from the Geographic South Pole near the Beardmore Glacier (Hammer and Hickerson 1994) at least three different theropods and a prosauropod. The remains os the prosauropod include a partial articulated foot that includes the astragalus and four metatarsals the distal end of a femur, and, possibly, a few cervical vertebrae. The Antarctic animal is among the largest of the prosauropods, and the size and features of the foot indicate it is related to the plateosaurids such as Plateosaurus from the Late Triassic of Germany and Lufengosaurus from the Early Jurassic of China. These animals were found associated with fragmentary remains of a tritylodont (synapsid) and a pterosaur. The Transantarctic Mountains are the largest Antarctics region where exploration is possible, The youngest rocks are Middle Jurassic in age, and they only occur on the highest peaks. The Jurassic dinosaurs of Antartcica were found at an elevation of over 4,000 meters in a tuffaceous siltstone (river bank deposit) high in the Falla Formation. Igneous rocks that have been dated at 177 million years (early Middle Jurassic) intrude the upper portion of the Falla Formation where the dinosaurs occur, indicating they lived prior to that time. The presence of a large tritylodont and a large plateosaurid prosauropod indicate more precisely an Early Jurassic (Pleinsbachian-Toarcian) age for the fauna from the Falla Formation. More than 100 bones collected from this site during a single eight week field season were concentrated in one small area of exposure approximately a meter thick and 5 meters wide. The Falla Formation overlies the Triassic [Fremouw Formation] in the southern portions of the Transantarctic Mountains. The [Fremouw Formation] has yielded faunas of Early to early Middle Triassic age that consist mainly of synapsids and temnospondyls (amphibians) that lived prior to the first appearance of the dinosaurs (Hammer, 1990). Dinosaurs Antarctopelta oliveroi Cryolophosaurus ellitio Elvisaurus Glacialisaurus hammeri
Ankylosaurus sp Hysylophodont sp Several theropod remains Prosauropod sp Fossilsites Falla Formation Hanson Formation
Santa Marta Formation
|
