Archelon is an extinct marine turtle from the Late Cretaceous, and is the largest turtle ever to have been documented, with the biggest specimen measuring 4.6 m (15 ft) from head to tail and 2.2–3.2 t in body mass. It is known only from the Pierre Shale and has one species, A. ischyros. In the past, the genus also contained A. marshii and A. copei, though these have been reassigned to Protostega and Kansastega, respectively. The genus was named in 1895 by American paleontologist George Reber Wieland based on a skeleton from South Dakota, who placed it into the extinct family Protostegidae. The leatherback sea turtle was once thought to be its closest living relative, but now, Protostegidae is thought to be a completely separate lineage from any living sea turtle.
Eonatator is an extinct genus of marine lizard belonging to the mosasaur family. It is a close relative of Halisaurus, and part of the same subfamily, the Halisaurinae. It is known from the Late Cretaceous of North America, Colombia and Sweden. Originally, this taxon was included within Halisaurus, but was placed in its own genus, which also led to the subfamily Halisaurinae being created for the two genera.
The Horseshoe Canyon Formation is a stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. It takes its name from Horseshoe Canyon, an area of badlands near Drumheller.
Protostega is an extinct genus of sea turtle containing a single species, Protostega gigas. Its fossil remains have been found in the Smoky Hill Chalk formation of western Kansas, time-equivalent beds of the Mooreville Chalk Formation of Alabama and Campanian beds of the Rybushka Formation. Fossil specimens of this species were first collected in 1871, and named by Edward Drinker Cope in 1872. With a total length of 3.9 metres (13 ft), it is the second-largest sea turtle that ever lived, second only to the giant Archelon, and one of the three largest turtle of all time along Archelon and Gigantatypus.
The Bearpaw Formation, also called the Bearpaw Shale, is a geologic formation of Late Cretaceous (Campanian) age. It outcrops in the U.S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, and was named for the Bear Paw Mountains in Montana. It includes a wide range of marine fossils, as well as the remains of a few dinosaurs. It is known for its fossil ammonites, some of which are mined in Alberta to produce the organic gemstone ammolite.
Isurus is a genus of mackerel sharks in the family Lamnidae, commonly known as the mako sharks. They are largely pelagic, fast predatory fish capable of swimming at speeds up to 50 km/h (31 mph).
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.
Corsochelys is an extinct genus of sea turtle that lived in the Late Cretaceous (Campanian). Zangerl (1960) named the type species, based upon remains found in Alabama within the Mooreville Chalk Formation.
Toxochelys is an extinct genus of marine turtle from the Late Cretaceous period. It is the most commonly found fossilized turtle species in the Smoky Hill Chalk, in western Kansas.
Bouliachelys is an extinct genus of sea turtle from Cretaceous Australia. It was originally described as a member of Protostegidae. In 2013 study it was considered to be a member of Dermochelyoidae, although later studies consider it as a protostegid again.
Desmatochelys is an extinct genus of sea turtles belonging to the family Protostegidae. This genus contains two known species, D. lowii and D. padillai. D. lowii was first discovered in 1895, followed by D. padillai in 2015. Having been estimated at over 120 million years old, D. padillai is currently the oldest known species of sea turtle.
Chelosphargis is an extinct genus of sea turtle from Upper Cretaceous of Alabama. Only one species has been described, Chelosphargis advena.
Euclastes is an extinct genus of sea turtles that survived the Cretaceous–Paleogene mass extinction. The genus was first named by Edward Drinker Cope in 1867, and contains three species. E. hutchisoni, was named in 2003 but has since been reassigned to the genus Pacifichelys, while E. coahuilaensis named in 2009 was reassigned as Mexichelys coahuilaensis in 2010.
Mexichelys is an extinct monotypic genus of sea turtle which lived in Mexico during the Cretaceous. The only species is Mexichelys coahuilaensis. Mexichelys was erected in 2010 as a replacement name for Euclastes coahuilaensis, a species named in 2009.
Puppigerus is an extinct genus of sea turtle from the Eocene. It is known from finds in the United States, the United Kingdom, Belgium, Denmark, and Uzbekistan.
Pancheloniidae is a clade of sea turtles It is defined as all turtles more closely related to cheloniid sea turtles than to dermochelyid ("leatherback") sea turtles.
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 2017.
Calcarichelys is an extinct genus of protostegid turtle from the Late Cretaceous of the Selma Formation in Alabama, and possibly from Angola. It contains only one species, C. gemma.
Acleistochelys is an extinct genus of large, bothremydid pleurodiran turtle known from Paleocene deposits in the Teberemt Formation of Mali. The type species, A. maliensis, was named for the country in which it was found. The holotype specimen consists of a nearly complete skull, shell fragments, pelvic fragments, and a cervical vertebra. It is most closely related to another Paleocene Malian side-necked turtle, Azabbaremys.
