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Saichangurvel Davidsoni
''Saichangurvel'' (meaning "beautiful lizard" in Mongolian) is an extinct genus of iguanian lizards from the Late Cretaceous of Mongolia. It is a member of a clade called Gobiguania, an exclusively Late Cretaceous group of iguanian lizards that was likely endemic to the Gobi Desert. The type species, ''Saichangurvel davidsoni'', was named by paleontologists Jack Conrad and Mark Norell of the American Museum of Natural History in 2007. It is known from a single nearly complete and fully articulated skeleton called IGM 3/858, which was found eroding from a block of sandstone during a thunderstorm at a fossil locality called Ukhaa Tolgod. IGM 3/858 comes from the Djadochta Formation, which is between 75 and 71 million years in age. Just as it is today, the Gobi was a desert during the Cretaceous. IGM 3/858 may have died in a collapsing sand dune, the rapid burial preserving its skeleton in pristine condition. ''Saichangurvel'' has a lightly built skull with a short snout and larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcification
Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Materials'' 12, 476-478 (2013). causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification. Calcification may also refer to the processes of normal mineral deposition in biological systems, such as the formation of stromatolites or mollusc shells (see Biomineralization). Signs and symptoms Calcification can manifest itself in many ways in the body depending on the location. In the pulpal structure of a tooth, calcification often presents asymptomatically, and is diagnosed as an incidental finding during radiographic interpretation. Individual teeth with calcified pulp will typically respond negatively to vitality testing; teeth with calcified pulp often lack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrodonta (lizard)
Acrodonta are a subclade of iguanian squamates consisting almost entirely of Old World taxa. Extant representation include the families Chamaeleonidae (chameleons) and Agamidae (dragon lizards), with at least over 500 species described. A fossil genus, ''Gueragama'', was found in Brazil, making it the only known American representative of the group. The group is eponymously named from their acrodont dentition, whereby the teeth are consolidated with the summit of the alveolar ridge of the jaw without sockets. There are, however, other animals that have acrodont dentition such as tuataras. Systematics Usually acrodonts are divided into two families Chamaeleonidae and Agamidae, there are a few studies that suggest chameleons are nested within Agamidae. In order to maintain the familial status of Chamaeleonidae some authors suggested placing the clades Uromastycinae and Leiolepidinae ''Leiolepis'', commonly known as butterfly lizards or butterfly agamas ( th, แย้), are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Priscagamidae
Priscagamidae is an extinct family of iguanian lizards known from the Late Cretaceous of Mongolia and China and the Eocene of India, spanning a range from 75 to 54 million years ago. It includes the genera '' Heterodontagama'', '' Mimeosaurus'', '' Phrynosomimus'', '' Priscagama'', and possibly '' Pleurodontagama''. The first fossils of priscagamids were found in the Djadochta and Khermeen Tsav formations of Mongolia. More recently they have been found in the Cambay Formation in India, leading to the naming of ''Heterodontagama'' in 2013. Priscagamidae was originally described as a subfamily of Agamidae called Priscagaminae in 1984, but it was reclassified as a distinct family in 1989. Most phylogenetic analyses (analyses of evolutionary relationships) still find a close relationship between Priscagamidae and Agamidae (both have been grouped under a clade called Chamaeleontiformes), although a 2015 study found it to be basal Basal or basilar is a term meaning ''base'', ''bot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chamaeleontiformes
Chamaeleontiformes is a hypothesized clade (evolutionary grouping) of iguanian lizards defined as all taxa sharing a more recent common ancestor with ''Chamaeleo chamaeleon'' (the common chamaeleon) than with '' Hoplocercus spinosus'' (the Brazilian spiny-tailed lizard), ''Polychrus marmoratus'' (bush lizard), or '' Iguana iguana'' (green iguana). It was named by paleontologist Jack Conrad in 2008 to describe a clade recovered in his phylogenetic analysis that included the extinct genus ''Isodontosaurus'', the extinct family Priscagamidae, and the living clade Acrodonta, which includes agamids and chameleons. It is a stem-based taxon and one of two major clades within Iguania, the other being Pleurodonta. Below is a cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") 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 d ... fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristiguana Brasiliensis
''Pristiguana'' is an extinct genus of primitive iguanids from the Maastrichtian Marília Formation of Brazil.''Pristiguana'' at .org The is ''P. brasiliensis''. Description ''Pristiguana'' was discovered in the Bauru Group of . Its discoverers said, in 1973, that it is the oldest fossil lizard in the family |
Huehuecuetzpalli Mixtecus
''Huehuecuetzpalli mixtecus'' is an extinct lizard from the Early Cretaceous (specifically the middle to late Aptian stage) Tlayúa Formation in Tepexi de Rodríguez, Central Mexico. Although it is not the oldest known lizard, ''Huehuecuetzpalli'' may be amongst the most basal members of Squamata (the group that includes lizards and snakes), making it an important taxon in understanding the origins of squamates. The generic name comes from the Nahuatl words ''huehuetl'' ("the ancient") and ''cuetzpalli'' ("lizard"), while the specific name refers to the La Mixteca region. Description Unique characteristics (autapomorphies) of ''Huehuecuetzpalli'' include a long pair of premaxilla bones at the tip of the upper jaw that contributes to an elongated snout and the apparent retraction of the external nares or nostril openings. At the top of the skull, a small rounded postfrontal and a hole called the parietal foramen between the junction of the frontal bone and the parietal bone (t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoyalacerta Sanzi
''Hoyalacerta'' is an extinct genus of lizard known from the type species ''Hoyalacerta sanzi'', which is from the Early Cretaceous Las Hoyas fossil site in Spain. ''Hoyalacerta'' was named in 1999 and is considered either a member of the group Iguania or a stem squamate, meaning that it lies outside the squamate crown group that includes all living lizards and snakes. ''Hoyalacerta'' is a small lizard with an elongated body and short limbs. It is thought to have spent most of its time on the ground. Several other lizards are also known from Las Hoyas, including '' Meyasaurus'' (thought to have lived near the water), '' Scandensia'' (thought to be a climber), and ''Jucaraseps ''Jucaraseps'' is an extinct genus of small squamate lizard known from the Early Cretaceous of Las Hoyas, Spain. It contains a single species, ''Jucaraseps grandipes''. It belonged to the clade Scincogekkonomorpha (containing scleroglossan squ ...'' (which, like ''Hoyalacerta'', probably lived on the gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iguania
Iguania is an infraorder of squamate reptiles that includes iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids. Using morphological features as a guide to evolutionary relationships, the Iguania are believed to form the sister group to the remainder of the Squamata, which comprise nearly 11,000 named species, roughly 2000 of which are iguanians. However, molecular information has placed Iguania well within the Squamata as sister taxa to the Anguimorpha and closely related to snakes. The order has been under debate and revisions after being classified by Charles Lewis Camp in 1923 due to difficulties finding adequate synapomorphic morphological characteristics. Most Iguanias are arboreal but there are several terrestrial groups. They usually have primitive fleshy, non-prehensile tongues, although the tongue is highly modified in chameleons. The group has a fossil record that extends back to the Early Jurassic (the oldest known member is '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, protein amino acid sequences, or morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An unrooted tree diagram (a network) makes no assumption about the ancestral line, and does ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") 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, so many differing evolutionary trees can be consistent with the same 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 (not an actual entity) 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 an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caniniform
In mammalian oral anatomy, the canine teeth, also called cuspids, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however, causing them to resemble incisors and leading them to be called ''incisiform''. They developed and are used primarily for firmly holding food in order to tear it apart, and occasionally as weapons. They are often the largest teeth in a mammal's mouth. Individuals of most species that develop them normally have four, two in the upper jaw and two in the lower, separated within each jaw by incisors; humans and dogs are examples. In most species, canines are the anterior-most teeth in the maxillary bone. The four canines in humans are the two maxillary canines and the two mandibular canines. Details There are generally four canine teeth: two in the upper (maxillary) and two in the lower (mandibular) arch. A canine is placed laterally to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
