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Glyptosaurinae
Glyptosaurinae is an extinct subfamily of anguid lizards that lived in the Northern Hemisphere during the Late Cretaceous and the Paleogene. Description Glyptosaurines are known primarily from their osteoderms, scale-like pieces of bone that are embedded in the skin and cover much of their bodies. The shape and extent of the osteoderms in glyptosaurines are similar to those seen in an unrelated group of lizards called Monstersauria, which includes the living Gila monster and beaded lizard. The osteoderms of glyptosaurines are unusually complex, consisting of four distinct layers of bony tissue. These tissues may have derived from both the dermis (the lower layer of the skin) and the epidermis (the outer layer of the skin) during their development in the embryo. The tissue forming the outermost layer of glyptosaurine osteoderms is similar to tooth enamel and has even been given its own name, osteodermine. Glyptosaurines have been split into the subgroups Melanosaurini and Glyptos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glyptosaurus
Glyptosaurinae is an extinct subfamily of anguid lizards that lived in the Northern Hemisphere during the Late Cretaceous and the Paleogene. Description Glyptosaurines are known primarily from their osteoderms, scale-like pieces of bone that are embedded in the skin and cover much of their bodies. The shape and extent of the osteoderms in glyptosaurines are similar to those seen in an unrelated group of lizards called Monstersauria, which includes the living Gila monster and beaded lizard. The osteoderms of glyptosaurines are unusually complex, consisting of four distinct layers of bony tissue. These tissues may have derived from both the dermis (the lower layer of the skin) and the epidermis (the outer layer of the skin) during their development in the embryo. The tissue forming the outermost layer of glyptosaurine osteoderms is similar to tooth enamel and has even been given its own name, osteodermine. Glyptosaurines have been split into the subgroups Melanosaurini and Glyptos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anguid
Anguidae refers to a large and diverse family of lizards native to the Northern Hemisphere. Common characteristics of this group include a reduced supratemporal arch, striations on the medial faces of tooth crowns, osteoderms, and a lateral fold in the skin of most taxa. The group includes the slowworms, glass lizards, and alligator lizards, among others. The family is divided into two subfamilies (Anguinae and Gerrhonotinae), and contains about 87 species in 8 genera. Morphology and reproduction Anguids have hard osteoderms beneath their scales giving them an armored appearance. Many of the species have reduced or absent limbs, giving them a snake-like appearance, while others are fully limbed. Body type varies among species, with sizes ranging from 10 cm to 1.5 m. The group includes oviparous and viviparous species, both of which can be observed in a single genus at times. Feeding and habitat These lizards are known carnivorous or insectivorous foragers, feeding p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peltosaurus
''Peltosaurus'' is an extinct genus of anguid lizard from North America that lived from the Eocene to the Oligocene. ''Peltosaurus'' belongs to the anguid subfamily Glyptosaurinae. The type species ''Peltosaurus granulosus'' was named in 1873 by American paleontologist Edward Drinker Cope. Many additional species have been named, but most have been reassigned to different genera. For example, ''Peltosaurus piger'', named in 1928, was reclassified as '' Odaxosaurus piger'', and ''P. jepseni'', named in 1942 from the Paleocene of Wyoming, but was later reclassified as '' Proxestops jepseni''. In 1955 a new species, ''Peltosaurus macrodon'', was named from the Eocene of California. Lizard bones from the Late Miocene of Nebraska were attributed to a new species of ''Peltosaurus'' called ''P. minimus'' in 1976, extending the fossil range of ''Peltosaurus'' and Glyptosaurinae into the Neogene. However, these bones were later referred to a genus of skinks called ''Eumeces'', meaning that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stenoplacosaurus
''Stenoplacosaurus'' is an extinct genus of glyptosaurine anguid lizards from the Eocene of Inner Mongolia, China. The genus is monotypic, containing only the species ''Stenoplacosaurus mongoliensis''. Taxonomy ''Stenoplacosaurus'' was originally named ''Helodermoides mongoliensis'' by Sullivan (1979) for remains found in the Shara Murun Formation of Inner Mongolia Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an autonomous region of the People's Republic of China. Its border includes most of the length of China's border with the country of Mongolia. Inner Mongolia also accounts for a ..., China. In their redescription of '' Placosaurus'', Sullivan and Auge (2006) transferred ''H. mongoliensis'' to ''Placosaurus'', as ''P. mongoliensis''. However, Sullivan and Dong (2018) found it to be generically distinct from the ''Placosaurus'' type species and renamed it ''Stenoplacosaurus''. References {{Extinct squamates, A. Anguids Eocene reptiles of Asia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helodermoides Tuberculatus
''Helodermoides'' is an extinct genus of anguid lizards from the Oligocene of North America. The genus is monotypic, including only the species ''Helodermoides tuberculatus''. ''Helodermoides'' belongs to an extinct subfamily of anguids called Glyptosaurinae. In addition to many fragmentary bones, several complete skeletons of ''Helodermoides'' are known. Like other glyptosaurines, ''Helodermoides'' was covered in small scale-like bones called osteoderms. The osteoderms covering its skull are hexagonal, tightly interlocking, raised, and rounded. One fossil of ''Helodermoides'' preserves a fused mass of osteoderms at the tip of a shortened tail, thought to represent healing after the end of the tail fell off. The tail would not have been able to grow back because the osteoderms formed a thick bony cap preventing growth. The ability to lose a tail, called autotomy, is also present in living anguid Anguidae refers to a large and diverse family of lizards native to the Northern Hem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helodermoides
''Helodermoides'' is an extinct genus of anguid lizards from the Oligocene of North America. The genus is monotypic, including only the species ''Helodermoides tuberculatus''. ''Helodermoides'' belongs to an extinct subfamily of anguids called Glyptosaurinae. In addition to many fragmentary bones, several complete skeletons of ''Helodermoides'' are known. Like other glyptosaurines, ''Helodermoides'' was covered in small scale-like bones called osteoderms. The osteoderms covering its skull are hexagonal, tightly interlocking, raised, and rounded. One fossil of ''Helodermoides'' preserves a fused mass of osteoderms at the tip of a shortened tail, thought to represent healing after the end of the tail fell off. The tail would not have been able to grow back because the osteoderms formed a thick bony cap preventing growth. The ability to lose a tail, called autotomy, is also present in living anguid Anguidae refers to a large and diverse family of lizards native to the Northern Hem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monstersauria
Monstersauria is a clade of anguimorph lizards, defined as all taxa more closely related to ''Heloderma'' than '' Varanus''. It includes ''Heloderma'', as well as several extinct genera, such as ''Estesia'', '' Primaderma'' and ''Gobiderma'', but it was found to be polyphyletic in the most recent and complete squamate phylogenetic analysis by Reeder ''et al.'' (2015). Classification Traditionally, Monstersauria was thought to include the modern Helodermatidae along with fossil genera such as ''Gobiderma'' and ''Estesia'' on the finding that it was a sister to Varanidae. But in more recent years, such as 2004 and 2008, more precise molecular studies have shown that the extant ''Heloderma'' is closer to Anguidae & kin than to Varanoidea. A large-scale integrated analysis on squamate phylogeny incorporating 737 characters of morphological and molecular data in 2015 analyzed the traditionally-monstersaurian fossil taxa along with the rest of the dataset, and what it found was a well- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraplacosauriops
''Paraplacosauriops'' (near ''Placosauriops'') is an extinct genus of anguid lizards from the middle Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ... of France. Taxonomy ''Paraplacosauriops'' was originally named ''Plestiodon quercyi'' by Filhol (1882) on the basis of dentary remains from fissure fill deposits in Quercy, France. Hoffstetter (1944) referred ''P. quercyi'' to the glyptosaurine genus '' Placosaurus'', which is likewise endemic to Europe.Hoffstetter, R. 1944. Sur les Scincidae fossiles. 1. Formes Européennes et Nord-Américaines. Bulletin du Muséum National d'Histoire Naturelle, 16: 547–553. However, Auge and Sullivan (2006) recognized ''quercyi'' as belonging to the tribe Melanosaurini and not a ''Placosaurus''-like glyptosaurin, so they erected ''Parapla ... [...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] |
Tooth Enamel
Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The other major tissues are dentin, cementum, and Pulp (tooth), dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. Calcium hardens the tooth enamel. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In contrast, a monophyletic group (a clade) includes a common ancestor and ''all'' of its descendants. The terms are commonly used in phylogenetics (a subfield of biology) and in the tree model of historical linguistics. Paraphyletic groups are identified by a combination of Synapomorphy and apomorphy, synapomorphies and symplesiomorphy, symplesiomorphies. If many subgroups are missing from the named group, it is said to be polyparaphyletic. The term was coined by Willi Hennig to apply to well-known taxa like Reptilia (reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene
The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (annum, Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognised as a formal stratigraphy, stratigraphic term, 'Tertiary' is still widely found in earth science literature and remains in informal use. Paleogene is often abbreviated "Pg" (but the United States Geological Survey uses the abbreviation PE for the Paleogene on the Survey's geologic maps). During the Paleogene, evolution of mammals, mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
