Chelidae is one of three living families of the turtle suborder Pleurodira, and are commonly called Austro-South American side-neck turtles. The family is distributed in Australia, New Guinea, parts of Indonesia, and throughout most of South America. It is a large family of turtles with a significant fossil history dating back to the Cretaceous. The family is entirely Gondwanan in origin, with no members found outside Gondwana, either in the present day or as a fossil.
Podocnemididae is a family of pleurodire (side-necked) turtles, once widely distributed. Most of its 41 genera and 57 species are now extinct. Seven of its eight surviving species are native to South America: the genus Peltocephalus, with two species, only one of which is extant ; and the genus Podocnemis, with six living species of South American side-necked river turtles and four extinct. There is also one genus native to Madagascar: Erymnochelys, the Madagascan big-headed turtle, whose single species E. madagascariensis.
Meiolaniidae is an extinct family of large, probably herbivorous stem-group turtles with heavily armored heads and clubbed tails known from South America and Australasia. Though once believed to be cryptodires, they are not closely related to any living species of turtle, and lie outside crown group Testudines, having diverged from them around the Middle Jurassic. They are best known from the last surviving genus, Meiolania, which lived in Australia from the Miocene until the Pleistocene, and insular species that lived on Lord Howe Island and New Caledonia during the Pleistocene and possibly the Holocene for the latter. Meiolaniids are part of the broader grouping of Meiolaniformes, which contains more primitive turtles species lacking the distinctive morphology of meiolaniids, known from the Early Cretaceous-Paleocene of South America and Australia.
Ninjemys oweni is an extinct large meiolaniid stem-turtle from Pleistocene Queensland and possibly New South Wales (Australia). It overall resembled its relative, Meiolania, save that the largest pair of horns on its head stuck out to the sides, rather than point backwards, the larger scales at the back of its skull and the tail club which is made up of only two tail rings rather than four. With a shell length of approximately 1 m it is a large turtle and among the largest meiolaniids. Ninjemys is primarily known from a well preserved skull and associated tail armor, which were initially thought to have belonged to the giant monitor lizard Megalania.
Protostegidae is a family of extinct marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, Archelon, had a head one metre (39 in) long. Like most sea turtles, they had flattened bodies and flippers for front appendages; protostegids had minimal shells like leatherback turtles of modern times.
Bothremydidae is an extinct family of side-necked turtles (Pleurodira) known from the Cretaceous and Cenozoic. They are closely related to Podocnemididae, and are amongst the most widely distributed pleurodire groups, with their fossils having been found in Africa, India, the Middle East, Europe, North America and South America. Bothremydids were aquatic turtles with a high morphological diversity, indicative of generalist, molluscivorous, piscivorous and possibly herbivorous grazing diets, with some probably capable of suction feeding. Unlike modern pleurodires, which are exclusively freshwater, bothremydids inhabited freshwater, marine and coastal environments. Their marine habits allowed bothremydids to disperse across oceanic barriers into Europe and North America during the early Late Cretaceous (Cenomanian). The youngest records of the group are indeterminate remains from Saudi Arabia and Oman, dating to the Miocene.
Niolamia is an extinct genus of South American meiolaniid turtle with a long and complex history. Like its relatives, Niolamia was a robust and heavily armored terrestrial turtle with large, horn like scales covering its head and a tail encased by rings of bone. This heavily armored build may have served the animal during intraspecific combat during courtship. Scans of the skull reveal that Niolamia likely had a great sense of smell but only low frequency hearing, indicating that these animals communicated more through chemical signals and smells than through sound.
The La Colonia Formation is a geological formation in Argentina whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.
Testudinata is the group of all tetrapods with a true turtle shell. It includes both modern turtles (Testudines) and many of their extinct, shelled relatives (stem-turtles), though excluding Odontochelys and Eorhynchochelys, which are placed in the more inclusive Pantestudines.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2011.
Patagoniaemys is an extinct genus of stem turtle which existed in central Patagonia, Chubut Province, Argentina during the late Cretaceous epoch. It is known from skull fragments and several postcranial elements including a nearly complete vertebral column recovered from the La Colonia Formation. It was first named by Juliana Sterli and Marcelo S. de la Fuente in 2011, and the type species is Patagoniaemys gasparinae.
The Malargüe Group is a group of geologic formations of the Neuquén Basin of the Mendoza, Neuquén, Río Negro and La Pampa Provinces in northern Patagonia, Argentina. The formations of the Malargüe Group range in age between the middle Campanian to Deseadan, an Oligocene age of the SALMA classification, straddling the Cretaceous–Paleogene boundary, about 79 million to 30 million years in age. The group overlies the older Neuquén Group, separated by an unconformity dated to 79 Ma. The rocks of the Malargüe Group comprise both marine and continental deposits which are over 400 m (1312 ft) thick in total.
Bonapartenykus is a monospecific genus of alvarezsauroid dinosaur from Argentina that lived during the Late Cretaceous (Campanian-Maastrichtian) in what is now the upper Allen Formation of the Río Negro Province. The type and only species, Bonapartenykus ultimus, is known from a nearly articulated but partial skeleton that was found in close association to two incomplete eggs and several clusters of eggshells belonging to the oogenus Arriagadoolithus. Bonapartenykus was named in 2012 by Federico L. Agnolin, Jaime E. Powell, Fernando E. Novas and Martin Kundrát. Bonapartenykus has an estimated length of 2.5 m (8.2 ft) and weight of 72 kg (159 lb), making it the largest member of the clade Alvarezsauroidea.
Warkalania is an extinct genus of Australian meiolaniid turtle from the Oligocene or early Miocene of Riversleigh, Queensland. While other meiolaniids are known for their elaborate headcrests or long horns, Warkalania only possesses very short horns that form a somewhat continuous ridge across the back of the head. The only known species of this genus, Warkalania carinaminor, is the oldest named meiolaniid turtle of Australia.
Prochelidella is an extinct genus of Early to Late Cretaceous chelid turtles from the Bajo Barreal, Candeleros, Cerro Barcino and Portezuelo Formations of the Cañadón Asfalto, Golfo San Jorge and Neuquén Basins in Patagonia, Argentina. It includes the following species:
Chubutemys was an extinct genus of meiolaniform turtle. It lived during the Early Cretaceous of Argentina, around the Albian-Aptian border, within the Puesto La Paloma Member of the Cerro Barcino Formation. It is known from most of the skeleton and carapace, and part of the skull.
Mesochelydia is a clade within Pantestudines, more inclusive than Perichelydia, but less than Testudinata. The clade is known from the Early Jurassic to the Present, and contains all Jurassic representatives of Testudinata aside from Australochelys. The ancestral condition for Mesochelydia is thought to be aquatic, as opposed to terrestrial for Testudinata. They are distinguished from more basal testudinatans by the presence of the following characters: strap like pectoral girdle, supramarginals absent, reduced posterior entoplastral process, eleven pairs of peripherals, elongate processus interfenestralis, paired basioccipital tubercles, fully formed cavum tympani and antrum postoticum, single vomer, confluent external nares, lacrimals and supratemporals absent.
The Salamanca Formation is a geologic formation in the Golfo San Jorge Basin of central Patagonia that yields well-preserved, well-dated fossils from the early Paleocene. Studies of these fossils are providing new data on plant and animal diversity following the end-Cretaceous extinction event.
Patagopelta is an extinct genus of nodosaurine dinosaur from the Late Cretaceous Allen Formation of Argentina. The genus contains a single species, P. cristata, known from a partial skeleton. Patagopelta is a very small ankylosaur, comparable in size to the dwarf nodosaurid Struthiosaurus, about 2 m (6.6 ft) long.
Chubutinectes is an extinct genus of elasmosaurid plesiosaur from the Late Cretaceous La Colonia Formation of Argentina. The genus contains a single species, C. carmeloi, known from a partial skeleton and associated gastroliths.
