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.
Paracryptodira is an extinct group of reptiles in the clade Testudinata, known from the Jurassic to Paleogene of North America and Europe. Initially treated as a suborder sister to Cryptodira, they were then thought to be a very primitive lineage inside the Cryptodira according to the most common use of the latter taxon. They are now often regarded as late-diverging stem-turtles, lying outside the clade formed by Cryptodira and Pleurodira. The paracryptodires are said to have phylogenic relationships, noted as primary subclades, within the Baenidae and Pleurosternidae. Within each subclade, lies many biodiverse turtles that are continuously being investigated and added to the fossil record. Paracryptodires are divided into three main groups, Compsemydidae, known from the Late Jurassic to Paleocene of North America and Europe, Pleurosternidae, known from the Late Jurassic to Early Cretaceous of North America and Europe, and Baenidae, known from the Early Cretaceous to Eocene of North America. The latter two groups are more closely related to each other than to Compsemys, forming the clade Baenoidea.
Emarginachelys cretacea is a turtle belonging to the group Cryptodira, known from well preserved fossils from the Maastrichtian stage of the Late Cretaceous of Montana. Its exact phylogenetic position within Cryptodira is uncertain; different authors considered it to be either the earliest described chelydrid or a fossil relative of kinosternoids.
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 2009.
Compsemys is an extinct genus of prehistoric turtles from the Late Cretaceous and Paleocene of North America and possibly Europe. The type species C. victa, first described by Joseph Leidy from the Hell Creek Formation in Montana in 1856, and another probable species C. russelli, described in 2012, from Paleocene deposits in France. Its affinites have long been uncertain, but it has recently been considered to be the most basal member of Paracryptodira, despite the clade first appearing in the Late Jurassic, and is sometimes included in its own family, Compsemydidae. A revision in 2020 found Compsemydidae to be more expansive, also containing Riodevemys and Selenemys from the Late Jurassic of Europe, and Peltochelys from the Early Cretaceous of Europe.
Cedrobaena is an extinct genus of turtle which existed in the Tiffanian Cedar Point Quarry, Wyoming and in the latest Maastrichtian Hell Creek Formation, United States. It was first named by Tyler R. Lyson and Walter G. Joyce in 2009 and the type species is Cedrobaena putorius.
Peckemys is an extinct genus of baenid turtle which existed in the Hell Creek Formation, United States during the late Cretaceous period. It was first named by Tyler R. Lyson and Walter G. Joyce in 2009 and the type species is Peckemys brinkman.
Gamerabaena is an extinct genus of baenid turtle which existed in North Dakota during the late Cretaceous Period. It is known from a single fragmentary skull that was found in the Maastrichtian-age Hell Creek Formation. It contains the species Gamerabaena sonsalla. Gamerabaena is similar to the genus Palatobaena, but it differs in its lack of a posterior expansion of the triturating surface, a somewhat rectangular skull, and a wide angle between the maxillae. Gamerabaena also has a lingual ridge on the inner side of the jaw that is not seen in Palatobaena.
Hutchemys is an extinct genus of softshell turtles from the late Cretaceous to the late Paleocene of New Mexico, Montana, Wyoming, Utah, and North Dakota, United States. It was first named by Walter G. Joyce, Ariel Revan, Tyler R. Lyson and Igor G. Danilov in 2009, and the type species is Hutchemys rememdium. H. rememdium is known from the holotype YPM PU 16795, which consists of a nearly complete postcranial skeleton, and from the referred specimen YPM PU 16781, found in the Ekalaka Member of the Fort Union Formation, Montana. Another referred specimen, YPM PU 14985, was found in the Cedar Point Quarry, Wyoming. The second species, H. arctochelys, is known from the holotype YPM PU 16319, a nearly complete carapace, and from the paratypes YPM PU 16320, YPM PU 16321, YPM PU 16322, YPM PU 16238. All specimens of H. arctochelys were recovered from the same quarry of the Tongue River Member, Fort Union Formation, near Burns Mine of Montana. A possible third species is represented by the unnamed specimen UCMP 130000 from the Paleocene Tullock Formation of Montana. Aspideretes? nassau (YPM PU 11566) from the Fort Union Formation, Duffy's Ranch of Sweet Grass County, Montana was also assigned to Hutchemys sp. A fourth species of Hutchemys, Hutchemys walkerorum, has been uncovered from the Hell Creek Formation of North Dakota. H. walkerorum is known from the holotype BDM 063, identified by the discovery and assembly of portions of its carapace. The fossil of H. walkerorum suggests that it was the only Hutchemys to live exclusively during the late Cretaceous era.
Palatobaena is an extinct genus of baenid turtle. It was first named by Gaffney in 1972 and the type species is Palatobaena bairdi. It based on a fragmentary skull from the Fort Union Formation of the Bighorn Basin of Wyoming. The two other species are P. gaffneyi and P. cohen which existed in Hell Creek Formation, North Dakota during the late Cretaceous period.
Cyclanorbinae, also known commonly as the flapshell turtles, is a subfamily of softshell turtles in the family Trionychidae. The subfamily is native to Africa and Asia.
The Trionychinae are a subfamily of turtles in the family Trionychidae.
Denazinemys was a genus of baenid turtle that lived in the Late Cretaceous of New Mexico. The holotype specimen, which D. nodosa was based on, USNM 8345, consists of a partial carapace and plastron. It came from the De-na-zin Member of the Kirtland Formation, and therefore, Denazinemys lived in the Kirtlandian land-vertebrate age. Many specimens other than the holotype have been assigned to Denazinemys.
Sichuanchelyidae is a family of extinct turtles in the clade Testudinata. It includes all perichelydians that are more closely related to Sichuanchelys than Meiolania, Helochelydra, or any extant turtles.
The Helochelydridae are an extinct family of stem-turtles known from fossils found in North America and Europe spanning the Early to Late Cretaceous.
Meiolaniformes is an extinct clade of stem-group turtles, defined as all taxa more closely related to Meiolania than to Cryptodira and Pleurodira. It is known from the Early Cretaceous to the Holocene of Australia, Oceania and South America. Some Eurasian taxa have been suggested to be part of the group, but this is disputed.
Sahonachelys is an extinct genus of pelomedusoid turtle from the Late Cretaceous (Maastrichtian) Maevarano Formation of Madagascar. The genus contains a single species, Sahonachelys mailakavava.
Sahonachelyidae is an extinct family of pelomedusoid turtles from the Late Cretaceous (Maastrichtian) Maevarano Formation of Madagascar. The clade was recognized in 2021 by Joyce et al., and contains two genera: Sahonachelys and Sokatra. The clade is characterized by the presence of a reduced contribution of the maxilla to the floor of the orbit, and, the presence of a distinct posterior process of the maxilla. The clade went extinct at the end of the Cretaceous period during the K-Pg extinction event.
Compsemydidae is an extinct family of turtles, likely belonging to the clade Paracryptodira. The earliest undisputed member is Tongemys from the Berriasian age of the Early Cretaceous; two Late Jurassic genera have also sometimes been included in the group, but may alternatively be members of the family Pleurosternidae. The genus Compsemys survived the Cretaceous–Paleogene extinction event and lasted until the Thanetian age of the Paleocene.
Plastomeninae is an extinct subfamily of softshell turtles that inhabited most of North America from the Cretaceous to the Eocene. Members of this subfamily are also known as plastomenines.
