Hallucicranians | |
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Skull of Lanthanosuchus watsoni , a lanthanosuchoidean | |
Skeleton of Scutosaurus karpinskii , a procolophonian | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | † Parareptilia |
Order: | † Procolophonomorpha |
Clade: | †Hallucicrania Lee, 1995 |
Subgroups | |
Synonyms | |
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Hallucicrania is an extinct clade of procolophonomorph parareptiles from the early Cisuralian epoch (middle Sakmarian stage) to the latest Triassic period (latest Rhaetian stage) of Africa, Antarctica, Asia, Australia, Europe, North America and South America. [1] [2]
A clade, also known as monophyletic group, is a group of organisms that consists of a common ancestor and all its lineal descendants, and represents a single "branch" on the "tree of life".
In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age but shorter than a period. The current epoch is the Holocene Epoch of the Quaternary Period. Rock layers deposited during an epoch are called a series. Series are subdivisions of the stratigraphic column that, like epochs, are subdivisions of the geologic timescale. Like other geochronological divisions, epochs are normally separated by significant changes in the rock layers to which they correspond.
In the geologic timescale, the Sakmarian is an age or stage of the Permian. It is a subdivision of the Cisuralian epoch or series. The Sakmarian lasted between 295 and 290.1 million years ago (Ma). It was preceded by the Asselian and followed by the Artinskian.
Hallucicrania was named Michael S. Y. Lee in 1995, and defined as the node-based taxon formed by Lanthanosuchoidea and Pareiasauria and all its descendants. [3] The clade Ankyramorpha named by the paleontologists Michael deBraga and Robert R. Reisz in 1996 was given nearly the same definition - "the most recent common ancestor of Procolophonia and Lanthanosuchoidea and all its descendants". [4] Under all current phylogenetic analyses, both clades contain the same species, and thus Ankyramorpha should be considered a junior synonym of Hallucicrania - a fact ignored in most of the recent publications, which keep applying Ankyramorpha for this clade. [5] [6]
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 1995.
Lanthanosuchoidea is an extinct superfamily of ankyramorph parareptiles from the late Cisuralian to the middle Guadalupian epochs of Europe, North America and Asia. It was named by the Russian paleontologist Ivachnenko in 1980, and it contains two families Acleistorhinidae and Lanthanosuchidae.
Robert Rafael Reisz is a Canadian paleontologist and specialist in the study of early amniote and tetrapod evolution.
The following cladogram is simplified after the phylogenetic analysis of MacDougall and Reisz (2014) and shows the placement of Hallucicrania (their Ankyramorpha) within Parareptilia. Relationships within emboldened terminal clades are not shown. [6]
A cladogram is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to descendants, nor does it show how much they have changed; nevertheless, many evolutionary trees can be inferred from a single cladogram. A cladogram uses lines that branch off in different directions ending at a clade, a group of organisms with a last common ancestor. There are many shapes of cladograms but they all have lines that branch off from other lines. The lines can be traced back to where they branch off. These branching off points represent a hypothetical ancestor which can be inferred to exhibit the traits shared among the terminal taxa above it. This hypothetical ancestor might then provide clues about the order of evolution of various features, adaptation, and other evolutionary narratives about ancestors. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational phylogenetics are now very commonly used in the generation of cladograms, either on their own or in combination with morphology.
Parareptilia is a subclass or clade of reptiles which is variously defined as an extinct group of primitive anapsids, or a more cladistically correct alternative to Anapsida. Whether the term is valid depends on the phylogenetic position of turtles, whose relationships to other reptilian groups are still uncertain.
Parareptilia |
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An anapsid is an amniote whose skull does not have openings (fenestra) near the temples. Traditionally, the Anapsida are the most primitive subclass of reptiles, the ancestral stock from which Synapsida and Diapsida evolved, making anapsids paraphyletic. It is however doubtful that all anapsids lack temporal fenestra as a primitive trait, and that all the groups traditionally seen as anapsids truly lacked fenestra.
Bolosauridae is an extinct family of ankyramorph parareptiles known from the latest Carboniferous (Gzhelian) or earliest Permian (Asselian) to the early Guadalupian epoch of North America, China, Germany, Russia and France. The bolosaurids were unusual for their time period by being bipedal, the oldest known tetrapods to have been so. Their teeth suggest that they were herbivores. The bolosaurids were a rare group and died out without any known descendants. The following cladogram shows the phylogenetic position of the Bolosauridae, from Johannes Müller, Jin-Ling Li and Robert R. Reisz, 2008.
The Procolophonia are a suborder of herbivorous reptiles that lived from the Middle Permian till the end of the Triassic period. They were originally included as a suborder of the Cotylosauria but are now considered a clade of Parareptilia. They are closely related to other generally lizard-like Permian reptiles such as the Millerettidae, Bolosauridae, Acleistorhinidae, and Lanthanosuchidae, all of which are included under the Anapsida or "Parareptiles".
Procolophonomorpha is an order or clade of early reptiles that appeared during the Middle Permian. It constitutes a diverse assemblage that includes a number of lizard-like forms, as well as more diverse types such as the pareiasaurs. The most important subclade, Procolophonia, is traditionally thought to be ancestral to turtles. Lee 1995, 1996, 1997 argues that turtles evolved from pareiasaurs, but this view is by no means held unanimously. Rieppel and deBraga 1996 and deBraga and Rieppel, 1997 argue that turtles evolved from sauropterygians.
Procolophonidae is an extinct family of parareptiles from the Permian and Triassic periods.
Nyctiphruretus is an extinct genus of nyctiphruretid parareptile known from the Guadalupian series of European Russia.
Belebey is an extinct genus of bolosaurid ankyramorph parareptile containing species known from the latest Carboniferous (Gzhelian) or earliest Permian (Asselian) to Guadalupian stage of Europe and Asia (China).
Macroleter is an extinct genus of nycteroleterid parareptile which existed in Oklahoma and Russia during the upper Permian period. It was a quite generalized primitive reptile, in many ways resembling their amphibian ancestors. It was first named by paleontologists Tverdochlebova and Ivachnenko in 1984. According to classification by Michel Laurin and Robert R. Reisz, the genus is a parareptile, belonging to the same branch as Millerettidae, Procolophonidae and other generalized anapsid reptiles. The type species is Macroleter poezicus from Upper Permian of Russia.
Leptoropha is an extinct genus of aquatic seymouriamorph reptiliomorphs known from the Middle Permian of Russia.
Colobomycter is an extinct genus of small parareptile known from the Early Permian of Oklahoma. The genus was first described from fossil remains in 1958, at which time it was believed to represent a synapsid, specifically, a pelycosaur. However, the discovery of new material and reexamination of the holotype led to its reclassification as a member of the Eureptilia. More recent studies indicate that Colobomycter is properly placed within the amniote clade Parareptilia, closely related to the taxon Acleistorhinus. Together, the two taxa form the Family Acleistorhinidae.
Delorhynchus is an extinct genus of lanthanosuchoid parareptile known from the late Early Permian Garber Formation of Comanche County, Oklahoma, south-central United States. It contains the type species D. priscus as well as a better preserved second species D. cifellii.
Acleistorhinidae is an extinct family of Early Permian-aged lanthanosuchoid parareptiles. Presently, the clade consists of only two taxa, Colobomycter and Acleistorhinus, both collected from the Permian of Oklahoma. Sister taxa include Chalcosaurus, Lanthaniscus and Lanthanosuchus.
Acleistorhinus (ah-kles-toe-RYE-nuss) is an extinct genus of parareptile known from the Early Permian of Oklahoma It is notable for being the earliest known anapsid reptile yet discovered. The morphology of the lower temporal fenestra of the skull of Acleistorhinus bears a superficial resemblance to that seen in early synapsids, a result of convergent evolution. Only a single species, A. pteroticus, is known, and it is classified in the Family Acleistorhinidae, along with Colobomycter.
Baeotherates is an extinct genus of Early Permian captorhinid reptile known from Oklahoma, United States.
Nyctiphruretidae is an extinct family of hallucicranian parareptiles known from the late Early to the late Middle Permian of European Russia and south-central United States.
Lanthaniscus is an extinct genus of lanthanosuchoid ankyramorph parareptile known from the Guadalupian epoch of Eastern Europe, Russia. Lanthaniscus was first named by M. F. Ivakhnenko in 1980 and the type species is Lanthaniscus efremovi. L. efremovi was originally described on the basis of the holotype PIN 3706/9 from Peza-1 locality, Krasnoshchel' Formation, of Arkhangelsk. Various authors had assigned it to the family Lanthanosuchidae, however Ivakhnenko who described an additional specimen of L. efremovi in 2008, assigned Lanthaniscus to its own family, the Lanthaniscidae. The additional specimen PIN 4543/2, was collected from the same formation as the holotype, from the Nisogora locality, which is slightly younger in age.
Pareiasauromorpha is a group of parareptilian amniotes from the Permian. It includes genera found all over the world, with many genera from Asia and South Africa. The clade was first used as a group by Linda A. Tsuji in 2011, in order to group the family Nycteroleteridae (nycteroleters) and the superfamily Pareiasauroidea (pareiasaurs). Pareiasauromorpha is considered to be a monophyletic node, the sister group to procolophonoids.
Abyssomedon is an extinct genus of a nyctiphruretid parareptile known from the late Early Permian Garber Formation of Comanche County, Oklahoma, south-central United States. It contains a single species, Abyssomedon williamsi, which represents the third known nyctiphruretid species, the oldest species of the family and the first to be discovered in North America.
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