The Trionychidae are a taxonomic family of a number of turtle genera, commonly known as softshell turtles. The family was erected by Leopold Fitzinger in 1826. Softshells include some of the world's largest freshwater turtles, though many can adapt to living in highly brackish areas. Members of this family occur in Africa, Asia, and North America, with extinct species known from Australia. Most species have traditionally been included in the genus Trionyx, but the vast majority have since been moved to other genera. Among these are the North American Apalone softshells that were placed in Trionyx until 1987.
Testudinoidea is a superfamily within the suborder Cryptodira of the order Testudines. It includes the pond turtles, Asian turtles, the monotypic big-headed turtle, and the tortoises.
Rafetus is a genus of highly endangered softshell turtles in the family Trionychidae. It is a genus of large turtles which are found in freshwater habitats in Eurasia.
The Fort Union Formation is a geologic unit containing sandstones, shales, and coal beds in Wyoming, Montana, and parts of adjacent states. In the Powder River Basin, it contains important economic deposits of coal, uranium, and coalbed methane.
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. 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.
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.
Gilmoremys is an extinct genus of softshell turtle which lived during the late Cretaceous of North Dakota, Montana and Wyoming, United States.
Baenidae is an extinct family of paracryptodiran turtles known from the Early Cretaceous to Eocene of North America. While during the Early Cretaceous they are found across North America, during the Late Cretaceous they are only found in Laramidia, having disappeared from Appalachia. The majority of lineages survived the K-Pg Extinction, but the family was extinct by the latest Eocene. The name of the type genus, Baena, appears to be of Native American origin, likely from the Arapaho be’enoo. They are primarily found in freshwater deposits, and are considered to be aquatic, with a largely generalist habit.
Sokatra is an extinct genus of pleurodiran turtle, known from the Cretaceous (Maastrichtian) Maevarano Formation of Madagascar. It belongs to the family Sahonachelyidae.
Araripemydidae is a family of freshwater aquatic turtles belonging to the order Pleurodira, known from the Early Cretaceous of South America and Africa. The family contains two recognised monotypic genera, Araripemys and Taquetochelys, from the Santana Group of Brazil and the Elrhaz Formation of Niger, respectively, which date to the Aptian-Albian stages of the Early Cretaceous. They are consider to be the most basal lineage within the Pelomedusoides. They are thought to have been specialised suction feeders. Laganemys was named in 2013 but was later determined to be synonymous with Taquetochelys.
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.
Neurankylus is an extinct genus of turtles in the family Baenidae that lived between 112 and 61 million years ago in Canada and the United States. It was originally placed within the monotypic family Neurankylidae, but it has since been placed in the Neurankylinae, alongside Trinitichelys. The type species, Neurankylus eximius, was described by Lawrence Lambe in 1902. The species N. lithographicus was discovered in the Milk River Formation (Canada), alongside the holotype of the pachycephalosaurid dinosaur Acrotholus audeti.
Americhelydia is a clade of turtles that consists of sea turtles, snapping turtles, the Central American river turtle and mud turtles, supported by several lines of molecular work. Prior to these studies some morphological and developmental work have considered sea turtles to be basal members of Cryptodira and kinosternids related to the trionychians in the clade Trionychoidea. Americhelydia and Testudinoidea, both clades within Durocryptodira, split a part during the early Cretaceous.
Baena is an extinct genus of baenid turtles that inhabited North America during the Late Cretaceous and early Paleogene. The genus name is thought to originate from a Native American language, possibly the Arapaho word for turtle, be’enoo.
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.
