The South Polar region of the Cretaceous comprised the continent of East Gondwana–modern day Australia, Zealandia, and Antarctica–a product of the break-up of Gondwana in the Cretaceous Period. The southern region, during this time, was much warmer than it is today, ranging from perhaps 4–8 °C (39–46 °F) in the latest Cretaceous Maastrichtian in what is now southeastern Australia. This prevented permanent ice sheets from developing and fostered polar forests, which were largely dominated by conifers, cycads, and ferns, and relied on a temperate climate and heavy rainfall. Major fossil-bearing geological formations that record this area are: the Santa Marta and Sobral Formations of Seymour Island off the Antarctic Peninsula; the Snow Hill Island, Lopez de Bertodano, and the Hidden Lake Formations on James Ross Island also off the Antarctic Peninsula; and the Eumeralla and Wonthaggi Formations in Australia.
Kronosaurus is an extinct genus of large short-necked pliosaur that lived during the Aptian to Albian stages of the Early Cretaceous in what is now Australia. The first known specimen was received in 1899 and consists of a partially preserved mandibular symphysis, which was first thought to come from an ichthyosaur according to Charles De Vis. However, it was 1924 that Albert Heber Longman formally described this specimen as the holotype of an imposing pliosaurid, to which he gave the scientific name K. queenslandicus, which is still the only recognized species nowadays. The genus name, meaning "lizard of Kronos", refers to its large size and possible ferocity reminiscent of the Titan of the Greek mythology, while the species name alludes to Queensland, the Australian state of its discovery. In the early 1930s, the Harvard Museum of Comparative Zoology sent an organized expedition to Australia that recovered two specimens historically attributed to the taxon, including a well known skeleton that is now massively restored in plaster. Several attributed fossils were subsequently discovered, including two large, more or less partials skeletons. As the holotype specimen does not present diagnostics to concretely distinguish Kronosaurus from other pliosaurids, these same two skeletons are proposed as potential neotypes for future redescriptions. Two additional species were proposed, but these are now seen as unlikely or belonging to another genus.
Koolasuchus is an extinct genus of brachyopoid temnospondyl in the family Chigutisauridae. Fossils have been found from Victoria, Australia and date back 125-120 million years ago to Barremian-Aptian stages of the Early Cretaceous. Koolasuchus is the youngest known temnospondyl. It is known from several fragments of the skull and other bones such as vertebrae, ribs, and pectoral elements. The type species Koolasuchus cleelandi was named in 1997. K. cleelandi was adopted as the fossil emblem for the state of Victoria, Australia on 13 January 2022.
Kakuru is a dubious genus of theropod dinosaur from the early Cretaceous Period.
Umoonasaurus is an extinct genus of plesiosaur belonging to the family Leptocleididae. This genus lived approximately 115 million years ago during the Early Cretaceous period, in shallow seas covering parts of what is now Australia. It was a relatively small animal around 2.5 metres (8.2 ft) long. An identifying trait of Umoonasaurus is three crest-ridges on its skull.
Opallionectes andamookaensis is the name given to a 5 m (16 ft) long cryptoclidian plesiosaur, which is thought to have lived during the early Cretaceous period, 115 million years ago, in shallow seas covering what is now Australia.
Cooyoo is an extinct genus of ichthyodectid fish known from the Lower Cretaceous. It contains a single species, C. australis, known from the Albian-aged Toolebuc and Allaru Formations of Queensland, Australia. C. australis was originally named by Arthur Smith Woodward as a species of Portheus in 1894, which was later amended to Xiphactinus.
The Eromanga Basin is a large Mesozoic sedimentary basin in central and northern Australia. It covers parts of Queensland, the Northern Territory, South Australia, and New South Wales, and is a major component of the Great Artesian Basin. The Eromanga Basin covers 1,000,000 km2 and overlaps part of the Cooper Basin.
The Toolebuc Formation is a geological formation that extends from Queensland across South Australia and the Northern Territory in Australia, whose strata date back to the Albian stage of the Early Cretaceous. Dinosaurs, pterosaurs, plesiosaurs, ichthyosaurs, protostegid turtles, sharks, chimaeroids and bony fish remains are among the fossils that have been recovered from the formation.
The Allaru Formation, also known as the Allaru Mudstone, is a geological formation in Queensland, Australia, whose strata date back to the Early Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
The Marree Subgroup, previously described as Maree Formation and Marree Formation, is a geological subgroup in the Eromanga Basin of South Australia whose strata date back to the Aptian. The subgroup was first described as a formation by Forbes in 1966. Dinosaur remains are among the fossils that have been recovered from the formation.
The Wonthaggi Formation is an informal geological formation in Victoria, Australia whose strata date back to the Early Cretaceous. It is part of the Strzelecki Group within the Gippsland Basin. Dinosaur remains are among the fossils that have been recovered from the formation. It is partially equivalent to the Eumeralla Formation.
The Eumeralla Formation is a geological formation in Victoria, Australia whose strata date back to the Early Cretaceous. It is Aptian to Albian in age. Dinosaur remains are among the fossils that have been recovered from the formation, particularly from the Dinosaur Cove locality.
Eromangasaurus is an extinct genus of elasmosaurid known from northern Queensland of Australia.
The Wallumbilla Formation is an Aptian geologic formation found in Australia. Plesiosaur and theropod remains are among the fossils that have been recovered from its strata.
The Paja Formation is an Early Cretaceous geologic formation of central Colombia. The formation extends across the northern part of the Altiplano Cundiboyacense, the Western Colombian emerald belt and surrounding areas of the Eastern Ranges of the Colombian Andes. In the subsurface, the formation is found in the Middle Magdalena Valley to the west. The Paja Formation stretches across four departments, from north to south the southernmost Bolívar Department, in Santander, Boyacá and the northern part of Cundinamarca. Well known fossiliferous outcrops of the formation occur near Villa de Leyva, also written as Villa de Leiva, and neighboring Sáchica.
Kryoryctes is a genus of prehistoric monotreme mammal from the Early Cretaceous (Albian) Eumeralla Formation of Victoria, Australia from the Otway Group of Dinosaur Cove. It is known only from a partial right humerus, estimated at 106 million years old, and contains one species, Kryoryctes cadburyi. The holotype, NMV P208094, was described in 2005 and is currently housed in the Museums Victoria Palaeontological Collection.
Leyvachelys is an extinct genus of turtles in the family Sandownidae from the Early Cretaceous of the present-day Altiplano Cundiboyacense, Eastern Ranges, Colombian Andes. The genus is known only from its type species, Leyvachelys cipadi, described in 2015 by Colombian paleontologist Edwin Cadena. Fossils of Leyvachelys have been found in the fossiliferous Paja Formation, close to Villa de Leyva, Boyacá, after which the genus is named. The holotype specimen is the oldest and most complete sandownid turtle found to date.
The Uitenhage Group is one of three geological groups, which comprise the onshore and offshore post-Karoo middle to lower Upper Mesozoic geological rock units in South Africa. Stratigraphically, the Uitenhage Group overlies the Suurberg Group and is overlain by the Algoa Group. It contains four formations that range in age from late Early Jurassic and late Early Cretaceous in age.
The Santana Group is a geologic group, formerly included as the middle part of the Araripe Group, in the Araripe Basin of northeastern Brazil. The group comprises the Crato, Ipubi and Romualdo Formations and is dated to the Aptian to Albian stages of the Early Cretaceous. The formations of the group were deposited in a lacustrine to subtidal shallow marine environment in the Araripe rift basin.
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