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Obamadon
''Obamadon'' is an extinct genus of polyglyphanodontian lizards from the Late Cretaceous of North America. Fossils have been found in the Hell Creek Formation of Montana and the Lance Formation of Wyoming. Researchers describe it as being distinguished by its "tall, slender teeth with large central cusps separated from small accessory cusps by lingual grooves." The type species was named ''Obamadon gracilis'' after United States president Barack Obama, "in reference to the tall, straight teeth, and the manner in which Mr. Obama has acted as a role model of good oral hygiene for the world." According to Nicholas R. Longrich of Yale University, the species "was probably a foot long, ndwith these tall, slender teeth it used to eat insects and plant matter." The lizard was identified as part of a search of museum collections to find snake and lizard species that had lived immediately prior to the Cretaceous–Paleogene extinction event, in which the dinosaurs (with the exception of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2013 In Paleontology
Plants Cnidarians Arthropods Bryozoans Brachiopods Molluscs Echinoderms Conodonts Fishes Amphibians Research * Laloy ''et al.'' (2013) reinterpret the Eocene frog species ''Rana cadurcorum'' from the Quercy Phosphorites (France) as a junior synonym of '' Thaumastosaurus gezei''. Newly named temnospondyls Newly named lepospondyls Newly named lissamphibians Turtles Research * A study on the anatomy of the brain and inner ear of the Jurassic turtle ''Plesiochelys etalloni'' is published by Paulina Carabajal ''et al.'' (2013). Newly named turtles Thalattosaurs Ichthyopterygians Lepidosauromorphs Newly named sauropterygians Newly named rhynchocephalians Newly named lizards Newly named snakes Archosauromorphs Newly named basal archosauromorphs Archosaurs Other reptiles Synapsids Non-mammalian synapsids Research * The postcranial skeleton of therocephalian '' Ictidosuchoides'' is described by Heidi Fourie (2013). New taxa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hell Creek Formation
The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions of Montana, North Dakota, South Dakota, and Wyoming. In Montana, the Hell Creek Formation overlies the Fox Hills Formation. The site of Pompeys Pillar National Monument is a small isolated section of the Hell Creek Formation. In 1966, the Hell Creek Fossil Area was designated as a National Natural Landmark by the National Park Service. It is a series of fresh and brackish-water clays, mudstones, and sandstones deposited during the Maastrichtian and Danian (respectively, the end of the Cretaceous period and the beginning of the Paleogene) by fluvial activity in fluctuating river channels and deltas and very occasional peaty swamp deposits along the low-lying eastern continental margin fronting the late Cretaceous Western Interior Seaway. Th ... [...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 and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyglyphanodontia
Polyglyphanodontia, also known as the Borioteiioidea, is an extinct clade of lizards from the Cretaceous that includes around a dozen genera. Polyglyphanodontians were the dominant group of lizards in North America and Asia during the Late Cretaceous. Most polyglyphanodontians are Late Cretaceous in age, though the oldest one, '' Kuwajimalla kagaensis'', is known from the Early Cretaceous (Valanginian to Hauterivian) Kuwajima Formation (Japan). Early Cretaceous South American taxon '' Tijubina'', and possibly also '' Olindalacerta'', might also fall within Polyglyphanodontia or be closely allied to the group, but if so, they would be two of only three Gondwanan examples of an otherwise Laurasian clade (the third one, and the only unambiguous one, being '' Bicuspidon hogreli'' from the Kem Kem Beds of Morocco). They produced a remarkable range of forms. Chamopsiids, including ''Chamops'', were characterized by large, blunt, crushing teeth, and were most likely omnivores. '' Macrocep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iguanidae
The Iguanidae is a family of lizards composed of the iguanas, chuckwallas, and their prehistoric relatives, including the widespread green iguana. Taxonomy Iguanidae is thought to be the sister group to the collared lizards (family Crotaphytidae); the two groups likely diverged during the Late Cretaceous, as that is when ''Pristiguana'' and ''Pariguana'', the two earliest fossil genera, are known from. The subfamily Iguaninae, which contains all modern genera, likely originated in the earliest Paleocene, at about 62 million years ago. The most basal extant genus, '' Dipsosaurus,'' diverged from the rest of Iguaninae during the late Eocene, about 38 million years ago, with '' Brachylophus'' following a few million years later at about 35 million years ago, presumably after its dispersal event to the Pacific. All other modern iguana genera formed in the Neogene period. A phylogenetic tree of Iguaninae is shown here: Description Iguanas and iguana-type species are divers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamiasaurus
''Lamiasaurus'' is an extinct genus of therapsids from the Tapinocephalus Assemblage Zone of the Karoo. It is known from an indeterminate jaw fragment that may be either titanosuchid or anteosaur Anteosaurs are a group of large, primitive carnivorous dinocephalian therapsids with large canines and incisors and short limbs, that are known from the Middle Permian of South Africa, Russia, China, and Brazil. Some grew very large, with skulls ...id.L.D. Boonstra, 1969, "The Fauna of the Tapinocephalus Zone", pg 36 References Tapinocephalians Prehistoric therapsid genera Prehistoric synapsids of Africa Fossil taxa described in 1914 Taxa named by D. M. S. Watson {{paleo-Therapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squamata
Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, it is also the second-largest order of extant (living) vertebrates, after the perciform fish. Members of the order are distinguished by their skins, which bear horny scales or shields, and must periodically engage in molting. They also possess movable quadrate bones, making possible movement of the upper jaw relative to the neurocranium. This is particularly visible in snakes, which are able to open their mouths very wide to accommodate comparatively large prey. Squamata is the most variably sized order of reptiles, ranging from the dwarf gecko (''Sphaerodactylus ariasae'') to the Reticulated python (''Malayopython reticulatus'') and the now-extinct mosasaurs, which reached lengths over . Among other reptiles, squamates are most close ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Clade analysis T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Splenial Bone
The splenial is a small bone in the lower jaw of reptiles, amphibians and birds, usually located on the lingual side (closest to the tongue The tongue is a muscular organ (anatomy), organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive system, digestive process, and is the primary organ of taste. The tongue's upper surfa ...) between the angular and surangular.Watson, D. M. S. (1912). LXVII.—On some reptilian lower jaws. Journal of Natural History, 10(60), 573-587. References Vertebrate anatomy {{Vertebrate anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
