Glacialisaurus was plant-eating dinosaur that lived in what is now Antarctica during the late Jurassic Period, between 186-182 million years ago. Although it is only known from a few bones, Glacialisaurus is estimated to have been about 20 feet (6 meters) when from snout to tail. The genus name translates to "Ice Reptile" in reference to the fact that it was discovered in the now icy Antarctic.
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| Watercolor life restoration of Glacialisaurus by Christopher DiPiazza. |
Glacialisaurus is considered a basal sauropodomorph, also known as a "prosauropod", which are generally considered the "more primitive" relatives of the long-necked sauropod dinosaurs, like Apatosaurus and Brachiosaurus. Like their more popular relatives, this group of dinosaurs had relatively long necks with small heads. Unlike them, many of these dinosaurs walked on their hind legs, some being obligate bipeds, and others able to switch between two and four limbs depending on what suited them. Their robust front limbs ended in five flexible fingers. The first finger on each hand typically had a particularly long and curved claw, possibly for defense against predators, battling rivals of the same species, grasping branches while feeding, or maybe something completely different nobody's imagined. They had long, somewhat rectangular skulls with slightly downturned jaws, lined with leaf-shaped teeth, ideal for shearing plants.
All that being said, Glacialisaurus, itself, is only known from a few limb bones, including part of a femur and some of the foot. Based on these bones, experts can deduct it was a close relative of other basal sauropodomorphs, like Massospondylus. Its bones were particularly robust compared to many of its relatives, meaning it would have been an overall robust animal for its length.
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| Images of Glacialisaurus' foot bones from Smeth Et al. referenced below. |
Perhaps the most interesting thing about Glacialisaurus isn't as much about its body but more its habitat, which is now frigid Antarctica. During the early Jurassic, however, Antarcticta was still attached to South America, Africa, Australia, and India. (India would later separate as an island and eventually crash into southern Asia) It was also closer to the equator at the time, which means it was much warmer than it is today. This is reflected in the kinds of fossils that have been found, including various plants that are known from warmer climates. Glacialisaurus also would have coexisted with other animals, including a still unnamed pterosaur related to Dimorphodon, at least one other smaller kind of still unnamed basal sauropodomorph, and the large meat-eating theropod, Cryolophosaurus, which may have hunted it.
References
Bomfleur, Benjamin; Pott, Christian; Kerp, Hans (2011). "Plant assemblages from the Shafer Peak Formation (Lower Jurassic), north Victoria Land, Transantarctic Mountains". Antarctic Science. 23 (2): 188–208.
Cantrill, David J.; Hunter, Morag A. (2005). "Macrofossil floras of the Latady Basin, Antarctic Peninsula". New Zealand Journal of Geology and Geophysics. 48 (3): 537–553.
Hammer, W. R., & Hickerson, W. J. (1996). Implications of an Early Jurassic vertebrate fauna from Antarctica. The Continental Jurassic, 215–218.
Rauhut, O. W. M.; Holwerda, F. M.; Furrer, H. (2020). "A derived sauropodiform dinosaur and other sauropodomorph material from the Late Triassic of Canton Schaffhausen, Switzerland". Swiss Journal of Geosciences. 113 (1): 8.
Smith, Nathan D.; Pol, Diego (2007). "Anatomy of a basal sauropodomorph dinosaur from the Early Jurassic Hanson Formation of Antarctica". Acta Palaeontologica Polonica. 52 (4): 657–674.
Smith, N.D; Hammer, W.R.; Makovicky, P.J. (2013). "New Dinosaurs from the Early Jurassic Hanson Formation of Antarctica, and Patterns of Diversity and Biogeography in Early Jurassic Sauropodomorphs". Geological Society of America Abstracts with Programs. 45 (7): 405–406.
