Triassic Vertebrates in the Transantarctic Mountains
- Mort D. Turner and
- John E. Splettstoesser
Published Online: 16 MAR 2013
Copyright 1986 by the American Geophysical Union.
Geology of the Central Transantarctic Mountains
How to Cite
Colbert, E. H. (1986) Triassic Vertebrates in the Transantarctic Mountains, in Geology of the Central Transantarctic Mountains (eds M. D. Turner and J. E. Splettstoesser), American Geophysical Union, Washington, D. C.. doi: 10.1029/AR036p0011
- Published Online: 16 MAR 2013
- Published Print: 1 JAN 1986
Print ISBN: 9780875901848
Online ISBN: 9781118664797
- Gondwana (Geology);
- Vertebrates, Fossil;
- Paleontology—Antarctic regions—Transantarctic Mountains
In the austral summer of 1967–1968 the discovery of a fragmentary amphibian jaw revealed the presence of fossil vertebrates in the Lower Triassic Fremouw Formation of the Transantarctic Mountains. This discovery led to the initiation of field work in Antarctica for the express purpose of finding Lower Triassic vertebrate fossils. Collections were made during two seasons, at Coalsack Bluff the first year and at Shackleton-McGregor glaciers the second season. The Fremouw Formation consists of cyclic series of continental sandstones, grading upward into fine-grained siltstones. It overlies the Permian Buckley Formation and, in turn, is overlain by the Triassic Falla Formation. There is every reason to think that the Fremouw Formation is equivalent to the Lower Triassic Lystrosaurus Zone, Middle Beaufort beds of the Karroo sequence in South Africa. The fauna from the Fremouw Formation is composed of a dipnoan fish belonging to the Family Ceratodontidae, labyrinthodont amphibians, and reptiles. Among the amphibians are two new genera-Austrobrachyops, comparable to Batrachosuchus from the Lystrosaurus Zone, and Cryobatrachus, related to the South African form Lydekkerina. There are also indications of other amphibians, perhaps of capitosaurid, rhytidosteid, and dissorophid relationships. The Fremouw reptiles likewise are of African complexion. Several species are conspecific with reptiles from the Lystrosaurus Zone; namely, the cotylosaurian, Procolophon trigoniceps, the dicynodonts (the most abundant fossils in the Fremouw, as is also true of the Lystrosaurus Zone), Lystrosaurus murrayi, Lystrosaurus curvatus, Lystrosaurus cf. McCaigi, and Myosaurus gracilis, the theriodonts Thrinaxodon liorhinus, Ericiolacerta parva, Pedaeosaurus parvus, Rhigosaurus glacials, and Theriodontia Incertae sedis, and the prolaceriform, Prolacerta broomi. Thecodont reptiles are also present. The Fremouw fauna is essentially a Lystrosaurus fauna, with some differences. Yet, in spite of differences, the resemblances are such as to indicate that in Early Triassic time East Antarctica was closely connected to South Africa, as part of a Gondwanaland continent.