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Ophidiomorpha
Ophidiomorpha is a clade composed of snakes and their primitive and early relatives proposed by Palci and Caldwell (2007)Palci, A., & Caldwell, M. W. (2007). Vestigial forelimbs and axial elongation in a 95 million-year-old non-snake squamate. Journal of Vertebrate Paleontology, 27(1), 1-7. The clade was defined as a node-based clade containing the most recent common ancestor of dolichosaurs, adriosaurs, '' Aphanizocnemus'', and fossil and extant Ophidia and all of its descendants. The existence of Ophidiomorpha as a clade may become problematic as it is placed within the Pythonomorpha, a clade that itself is not universally agreed upon containing mosasaurs and snakes, their most recent common ancestor and all of its descendants. Indeed, most 20th-century herpetologists and paleontologists rejected this idea and sought instead to demonstrate a close relationship between mosasaurs and varanid lizards. Pythonomorpha was later resurrected by a number of paleontologists (Lee, 1997; C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adriosaurus
''Adriosaurus'' is an extinct genus of squamate which lived in what is now Slovenia and other parts of Europe during the Late Cretaceous. It was snake-like and grew up to in length. This is the first fossil record of vestigial limbs in lizards. It lost its manus and forearm completely in order to elongate its axial skeleton. These unique anatomical features led to discussions of the evolutionary patterns of limb reduction in Squamata.Alessandro Palci and Michael W. Caldwell. 2007. Vestigial Forelimbs and Axial Elongation in a 95 Million-Year-Old Non-Snake Squamate. Journal of Vertebrate Paleontology Vol. 27, No. 1. pp. 1-7 ''Adriosaurus'' includes three species: ''A. microbrachis'' (“micro”, meaning small, and “brachis”, meaning arm, referring to the vestigial forelimb composed of only the humerus), ''A skrbinensis'' (named after the location where they found the fossil, Skrbina, northwest of Komen, Slovenia) and ''A. suessi''. However, ''A. microbrachis'' lacks many cru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolichosauridae
Dolichosauridae (from Latin, ''dolichos'' = "long" and Greek ''sauros''= lizard) is a family of Cretaceous aquatic ophidiomorphan lizards closely related to the snakes and mosasaurs. Description ''Dolichosaurus'' was a small marine squamate at about 0.5 to 1 meter in total length. ''Coniasaurus'' was similarly sized at about 0.5 meters in length. They were elongated (especially apparent in the neck) marine lizards with reduced limbs and small, thin heads. Dolichosaurs may have occupied a niche similar to the earlier nothosaurs and modern sea snakes, in using their thin heads to feed in crevices and narrow spaces along coral reefs and rocky shores. One of the earliest dolichosaurs, '' Kaganaias'' from Barremian, probably lived in freshwater environment unlike other members in the family. The degree to which the limbs were reduced suggest that the dolichosaurs would have been unable to generate any significant movement on land, and they thus likely spent most of their time u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophidia
__FORCETOC__ Ophidia (also known as Pan-Serpentes) is a group of squamate reptiles including modern snakes and reptiles more closely related to snakes than to other living groups of lizards. Ophidia was defined as the "most recent common ancestor of ''Pachyrhachis'' and Serpentes (modern snakes), and all its descendants" by Lee and Caldwell (1998: 1551). The latter author has used Ophidia in a manner inconsistent with this definition, using it to incorporate other more basal stem-snakes, such as the Late Cretaceous ''Najash rioegrina'' or the Jurassic ''Diablophis'' and ''Portugalophis''. The clade name Ophidia derives from the Ancient Greek word (), meaning "small snake". Evolution Modern snakes are thought to have evolved from either burrowing or aquatic lizards during the mid-Cretaceous period, and the earliest known fossils date to around 112 Ma ago. However, the relationship between modern snake and more primitive snake ancestors, many of which retained hind limbs, is l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythonomorpha
Pythonomorpha was originally proposed by paleontologist Edward Drinker Cope (1869) as a reptilian order comprising mosasaurs, which he believed to be close relatives of Ophidia (snakes). The etymology of the term Pythonomorpha comes from the Greek ''Python'' (a monstrous snake from Greek mythology) and ''morphe'' ("form"), and refers to the generally serpentine body plan of members of the group. Cope wrote, "In the mosasauroids, we almost realize the fictions of snake-like dragons and sea-serpents, in which men have been ever prone to indulge. On account of the ophidian part of their affinities, I have called this order Pythonomorpha." Cope incorporated two families, the Clidastidae (now defunct but including only ''Clidastes'') and the Mosasauridae (including ''Macrosaurus'' Tylosaurus.html"_;"title="=Tylosaurus">''Tylosaurus''_''Mosasaurus.html" ;"title="Tylosaurus">''Tylosaurus''.html" ;"title="Tylosaurus.html" ;"title="=Tylosaurus">''Tylosaurus''">Tylosaurus.html" ;"title="=Ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,British Geological Survey. 2011Stratigraphic framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf: research report RR/11/06 British Geological Survey, Keyworth, Nottingham. the Daohugou Beds in China, the Itat Formation in Russia, and the Isalo III Formation of western Madagascar. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subduction zone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene has been identified with the current warm period, known as MIS 1. It is considered by some to be an interglacial period within the Pleistocene Epoch, called the Flandrian interglacial.Oxford University Press – Why Geography Matters: More Than Ever (book) – "Holocene Humanity" section https://books.google.com/books?id=7P0_sWIcBNsC The Holocene corresponds with the rapid proliferation, growth and impacts of the human species worldwide, including all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snake
Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads (cranial kinesis). To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. Lizards have evolved elongate bodies without limbs or with greatly reduced limbs about twenty-five times independently via convergent evolution, leading to many lineages of legless lizards. These resemble snakes, but several common groups of legless lizards have eyelids and external ears, which snakes lack, altho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphanizocnemus
''Aphanizocnemus'' is an extinct genus of lizard from Lebanon. It is a marine lizard that lived during the Late Cretaceous. It is often classified in the family Dolichosauridae as a close relative of snakes, although some studies have placed it as an even closer relative to snakes than dolichosaurids. Only one species of ''Aphanizocnemus'' is known, the type species ''A. libanensis''. ''A. libanensis'' was named in 1997 on the basis of a single complete skeleton. Although the type locality is unknown, it is said to "almost certainly" originate from the Sannine Formation The Sannine Formation, also called the Sannine Limestone, is a Cretaceous geologic formation in Lebanon. Description It is primarily Cenomanian in age. The formation laterally varies from east to west; the western lowland "coastal" sequence i .... ''Aphanizocnemus'' is about long, and the tail makes up half of its length. The hands and feet are very large in comparison to the limb bones. The flattened sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Earliest Late Cretaceous with 42 described genera. During the last 20 million years of the Cretaceous period (Turonian–Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They themselves became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago. Description Mosasaurs breathed air, were powerful swimmers, and were well-adapted to living in the warm, shallow inland seas prevalent during the Late Cretaceous period. Mosasaurs were so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herpetologist
Herpetology (from Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians (gymnophiona)) and reptiles (including snakes, lizards, amphisbaenids, turtles, terrapins, tortoises, crocodilians, and the tuataras). Birds, which are cladistically included within Reptilia, are traditionally excluded here; the scientific study of birds is the subject of ornithology. Thus, the definition of herpetology can be more precisely stated as the study of ectothermic (cold-blooded) tetrapods. Under this definition "herps" (or sometimes "herptiles" or "herpetofauna") exclude fish, but it is not uncommon for herpetological and ichthyological scientific societies to collaborate. Examples include publishing joint journals and holding conferences in order to foster the exchange of ideas between the fields, as the American Society of Ichthyologists and He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varanid
The Varanidae are a family of lizards in the superfamily Varanoidea within the Anguimorpha group. The family, a group of carnivorous and frugivorous lizards, includes the living genus '' Varanus'' and a number of extinct genera more closely related to ''Varanus'' than to the earless monitor lizard (''Lanthanotus''). ''Varanus'' includes the Komodo dragon (the largest living lizard), crocodile monitor, savannah monitor, the goannas of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the earless monitor lizard and chinese crocodile lizard. The oldest members of the family are known from the Late Cretaceous of Mongolia. Taxonomy The Varanidae were defined (using morphological characteristics) by Estes, de Queiroz and Gauthier (1988) as the clade containing the most recent common ancestor of ''Lanthanotus'' and ''Varanus'' and all of its descendants. A similar definition was formulated by Conrad ''et al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladistic
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics ( synapomorphies'')'' that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms ''worms'' or ''fishes'' were used within a ''strict'' cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a 'grade', which are fruitless to precisely delineate, especially when including extinct species. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
