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Bayan Mandahu Formation
The Bayan Mandahu Formation (also known as Wulansuhai Formation or Wuliangsuhai Formation) is a geological unit of "redbeds" located near the village of Bayan Mandahu in Inner Mongolia, China, in the Gobi Desert. It dates from the late Cretaceous Period (geology), Period. Laid down in the Campanian, it is dated somewhat uncertainly to between 75 and 71 mya (million years ago). Description The paleoenvironment it preserves was semi-arid and characterized by Alluvium, alluvial (stream-deposited) and Aeolian processes, eolian (wind-deposited) sediments. The formation is known for its vertebrate fossils, most of which are preserved in unstructured sandstone, indicating burial by wind-blown Dust storm, sandstorms. Paleofauna of the Bayan Mandahu Formation The fauna of the Bayan Mandahu is very similar in composition to the nearby Djadochta Formation, and the two may have been deposited at roughly the same time. These two formations share many of the same Genus, genera, but differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Djadochta Formation
The Djadochta formation (sometimes transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation in Central Asia, Gobi Desert, dating from the Late Cretaceous period, about 75 million to 71 million years ago. The type locality is the Bayn Dzak locality, famously known as the Flaming Cliffs. Reptile (including dinosaur) and mammal remains are among the fossils recovered from the formation. Excavation history The Djadochta formation was first documented and explored—though only a single locality—during paleontological expeditions of the American Museum of Natural History in 1922–1925, which were part of the Central Asiatic expeditions. The expeditions were led by Roy Chapman Andrews, in company of Walter Willis Granger as chief paleontologist and field team. The team did extensive exploration at the Bayn Dzak (formerly Shabarakh Usu) region, which they nicknamed flaming cliffs, given that at sunset the ... [...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 iguanians are arboreal but there are several terrestrial groups. They usually have primitive fleshy, non-prehensile tongues, although the tongue is highly modified in chameleons. Today they are scattered occurring in Madagascar, the Fiji and Friendly Islands and Western Hemispher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphisbaenia
Amphisbaenia (called amphisbaenians or worm lizards) is a group of typically legless lizards, comprising over 200 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes. As many species have a pink body and scales arranged in rings, they have a superficial resemblance to earthworms. While the genus '' Bipes'' retains forelimbs, all other genera are limbless. Phylogenetic studies suggest that they are nested within Lacertoidea, closely related to the lizard family Lacertidae. Amphisbaenians are widely distributed, occurring in North America, Europe, Africa, South America, Western Asia and the Caribbean. Most species are less than long. Description 200px, left, Close-up of the head of'' Rhineura'' Despite a superficial resemblance to some primitive snakes, amphisbaenians have many unique features that distinguish them from other reptiles. Internally, their right lung is reduced in size to fit their narrow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoeucrocodylia
Mesoeucrocodylia is the clade that includes Eusuchia and crocodyliforms formerly placed in the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day. Diagnosis It was long known that Mesosuchia was an evolutionary grade, a hypothesis confirmed by the phylogenetic analysis of Benton and Clark (1988) which demonstrated that Eusuchia (which includes all living crocodylian species) was nested within Mesosuchia. Due to the paraphyly of Mesosuchia, Mesoeucrocodylia was erected to replace Mesosuchia. Several anatomical characteristics differentiate Mesoeucrocodylia from the other crocodylomorph clades. The frontal bones of the skull are fused together into a single compound element, for example. Mesoeucrocodylians possess something of a secondary palate, formed by the posterior extension of sutured palatine bones. The otic aperture of the members of this clade is blocked posteriorly by the squamosal bone. Classification Phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shamosuchus
''Shamosuchus'' is an extinct genus of neosuchian crocodyliform Crocodyliformes is a clade of Crurotarsi, crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the ... that lived during the Late Cretaceous (Campanian) period in what is now the Djadochta Formation of Mongolia, approximately 75 million to 71 million years ago. Paleobiology ''Shamosuchus'' reached up to 4 m long and had a rostrum of moderate length. The eye and nasal openings were not raised above the skull as in modern crocodilians, so that the animal would have to raise its head completely out of the water to breathe. As this cranial morphology does not suit an ambush predator, it lends support to the idea of a diet of aquatic invertebrates. The teeth were adapted to crush bivalves, gastropods, and other animals with a shell or exoskeleton. The genus was named in 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crocodylomorph
Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. Extinct crocodylomorphs were considerably more ecologically diverse than modern crocodillians. The earliest and most primitive crocodylomorphs are represented by " sphenosuchians", a paraphyletic assemblage containing small-bodied, slender forms with elongated limbs that walked upright, which represents the ancestral morphology of Crocodylomorpha. These forms persisted until the end of the Jurassic. During the Jurassic, crocodylomorphs morphologically diversified into numerous niches, with the subgroups Neosuchia (which includes modern crocodilians) and the extinct Thalattosuchia adapting to aquatic life, while some terrestrial groups adopted herbivorous and omnivorous lifestyles. Terrestrial crocodylomorphs would continue to co-exist alongside aquatic forms until becoming extinct du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velociraptor Osmolskae
''Velociraptor'' (; ) is a genus of small dromaeosaurid dinosaurs that lived in Asia during the Late Cretaceous epoch, about 75 million to 71 million years ago. Two species are currently recognized, although others have been assigned in the past. The type species is ''V. mongoliensis'', named and described in 1924. Fossils of this species have been discovered in the Djadochta Formation, Mongolia. A second species, ''V. osmolskae'', was named in 2008 for skull material from the Bayan Mandahu Formation, China. Smaller than other dromaeosaurids like ''Deinonychus'' and ''Achillobator'', ''Velociraptor'' was about long with a body mass around . It nevertheless shared many of the same anatomical features. It was a bipedal, feathered carnivore with a long tail and an enlarged sickle-shaped claw on each hindfoot, which is thought to have been used to tackle and restrain prey. ''Velociraptor'' can be distinguished from other dromaeosaurids by its long and low skull, with an upturned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoceratops Hellenikorhinus
''Protoceratops'' (; ) is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 75 to 71 million years ago. The genus ''Protoceratops'' includes two species: ''P. andrewsi'' and the larger ''P. hellenikorhinus''. The former was described in 1923 with fossils from the Mongolian Djadokhta Formation, and the latter in 2001 with fossils from the Chinese Bayan Mandahu Formation. ''Protoceratops'' was initially believed to be an ancestor of ankylosaurians and larger ceratopsians, such as ''Triceratops'' and relatives, until the discoveries of other protoceratopsids. Populations of ''P. andrewsi'' may have evolved into ''Bagaceratops rozhdestvenskyi'' through anagenesis. ''Protoceratops'' were small ceratopsians, up to long and around in body mass. While adults were largely quadrupedal, juveniles had the capacity to walk around bipedally if necessary. They were characterized by a proportionally large skull, short and stiff neck, and neck fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velociraptor Mongoliensis
''Velociraptor'' (; ) is a genus of small dromaeosaurid dinosaurs that lived in Asia during the Late Cretaceous epoch, about 75 million to 71 million years ago. Two species are currently recognized, although others have been assigned in the past. The type species is ''V. mongoliensis'', named and described in 1924. Fossils of this species have been discovered in the Djadochta Formation, Mongolia. A second species, ''V. osmolskae'', was named in 2008 for skull material from the Bayan Mandahu Formation, China. Smaller than other dromaeosaurids like ''Deinonychus'' and '' Achillobator'', ''Velociraptor'' was about long with a body mass around . It nevertheless shared many of the same anatomical features. It was a bipedal, feathered carnivore with a long tail and an enlarged sickle-shaped claw on each hindfoot, which is thought to have been used to tackle and restrain prey. ''Velociraptor'' can be distinguished from other dromaeosaurids by its long and low skull, with an uptur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoceratops Andrewsi
''Protoceratops'' (; ) is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 75 to 71 million years ago. The genus ''Protoceratops'' includes two species: ''P. andrewsi'' and the larger ''P. hellenikorhinus''. The former was described in 1923 with fossils from the Mongolian Djadokhta Formation, and the latter in 2001 with fossils from the Chinese Bayan Mandahu Formation. ''Protoceratops'' was initially believed to be an ancestor of ankylosaurians and larger ceratopsians, such as ''Triceratops'' and relatives, until the discoveries of other protoceratopsids. Populations of ''P. andrewsi'' may have evolved into '' Bagaceratops rozhdestvenskyi'' through anagenesis. ''Protoceratops'' were small ceratopsians, up to long and around in body mass. While adults were largely quadrupedal, juveniles had the capacity to walk around bipedally if necessary. They were characterized by a proportionally large skull, short and stiff neck, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kryptobaatar Mandahuensis
''Kryptobaatar'', also known as ''Gobibaatar'' or ''Tugrigbaatar'', is an extinct mammalian genus dating from the Upper Cretaceous Period and identified in Central Asia. This animal was a member of the extinct order of Multituberculata within the suborder Cimolodonta, and was a member of the family Djadochtatheriidae. It lived contemporaneously with some of the dinosaurs. Its skull had a length of perhaps 3 cm. The generic name ''Kryptobaatar'' is derived from Greek : ''kruptós'', "hidden," (alludes to the ventral position of infraorbital foramen) and Mongolian : ''baatar'', "hero" (alludes to the name of the capital of Mongolia, Ulan Baatar). The specific name ''dashzevegi'' is named in honour of Mongolian palaeontologist Demberelyin Dashzeveg. The derivation of its synonym ''Gobibaatar parvus'' is Gobi (occurring in the Gobi Desert, Mongolia) and baatar ("a hero", the same as ''Kryptobaatar''). Another synonym ''Tugrigbaatar saichanensis'' is a generic name derived from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
