|
Lakota Formation
The Lakota Formation is a sequence of rocks of early Cretaceous (Berriasian to Barremian) age from Western North America. Located in South Dakota, the name of the formation is derived from the Lakota Native American tribe. There are two units of the Lakota Formation, the Chilson Member (upper Berriasian to Valanginian) and the underlying Fuson Member (upper Valanginian to early Barremian). A Berriasian-Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceou ... age for the Chilson Member has been extrapolated by means of ostracods and charophytes. Vertebrate paleofauna Dinosaurs Mammals Turtles References Geologic formations of South Dakota Cretaceous geology of South Dakota Cretaceous Manitoba Cretaceous geology of Nebraska Berriasian Stage Valanginian Sta ... [...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 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 Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iguanodontia
Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include ''Camptosaurus'', ''Dryosaurus'', ''Iguanodon'', ''Tenontosaurus'', and the hadrosaurids or "duck-billed dinosaurs". Iguanodontians were one of the first groups of dinosaurs to be found. They are among the best known of the dinosaurs, and were among the most diverse and widespread herbivorous dinosaur groups of the Cretaceous period. Classification Iguanodontia is often listed as an infraorder within a suborder Ornithopoda, though Benton (2004) lists Ornithopoda as an infraorder and does not rank Iguanodontia. Traditionally, iguanodontians were grouped into the superfamily Iguanodontoidea and family Iguanodontidae. However, phylogenetic studies show that the traditional "iguanodontids" are a paraphyletic grade leading up to the hadrosaurs (duck-billed dinosaurs). Groups like Iguanodontoidea are sometimes still used as unranked clades ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spalacotheriid
Spalacotheriidae is a family of extinct mammals belonging to the paraphyletic group ' Symmetrodonta'. They lasted from the Early Cretaceous to the Campanian in North America, Europe, Asia and North Africa. Spalacotheriids are characterised by having molar teeth with three molar cusps sitting at acute angles to one another.Martin, T., 2018. 6. Mesozoic mammals—early mammalian diversity and ecomorphological adaptations. In Mammalian evolution, diversity and systematics (pp. 199-300). De Gruyter. The shape of their teeth as well as their long lower jaw indicate a carnivorous/insectivorous diet. A sub-group of Spalacotheriidae, the spalacolestines, lack a Meckelian groove in the jaw, indicating that they had a modern ear anatomy. Genera * '' Akidolestes'' * '' Infernolestes'' * ''Spalacotherium ''Spalacotherium'' is a genus of extinct mammal from the Early Cretaceous of Europe. The type species ''Spalacotherium tricuspidens'' was originally named by Richard Owen in 1854, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multituberculate
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, and reached a peak diversity during the Late Cretaceous and Paleocene. They eventually declined from the mid Paleocene onwards, disappearing from the known fossil record in the late Eocene. They are the most diverse order of Mesozoic mammals with more than 200 species known, ranging from mouse-sized to beaver-sized. These species occupied a diversity of ecological niches, ranging from burrow-dwelling to squirrel-like arborealism to jerboa-like hoppers. Multituberculates are usually placed as crown mammals outside either of the two main groups of living mammals—Theria, including placentals and marsupials, and MonotremataAgustí-Antón 2002, pp 3-4—but usually as closer to Theria than to monotremes. They are considered to be close ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plagiaulacidae
Plagiaulacidae is a family of fossil mammals within the order Multituberculata. Remains are known from the Upper Jurassic and earliest Cretaceous of North America and Europe. They were among the more derived representatives of the informal suborder of "Plagiaulacida Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs". Plagiaulacids are a paraphyletic grouping, containing all multituberculates that lie ...". The taxon Plagiaulacidae was named by Gill T.N. in 1872. It is also known as Bolodontidae, a name developed by Osborn H.F. in 1887. References * Gill (1872), "Arrangement of the families of mammals". With analytical tables. ''Smithsonian Miscellaneous Collections'' 230, p. 1-98. * Osborn (1887), "On the structure and classification of the British Mesozoic Mammalia". ''Proc. of the Nat. Academy of Sciences'' 39, p. 282-292. * Kielan-Jaworowska Z. and Hur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolodon
''Bolodon'' ("lump tooth" from Ancient Greek βῶλος (bôlos), “clod, lump” + ὀδών (odṓn), "tooth") is a genus of extinct mammal from the Lower Cretaceous of Europe and North America. It was a member of the extinct order of Multituberculata and belongs to the suborder Plagiaulacida and family Plagiaulacidae. Type species The type species, ''Bolodon crassidens'', is known from fossils of the Lower Cretaceous of England from the Lulworth Formation in Durlston Bay, Dorset. The species ''Bolodon elongatus'' is possibly not referable to this genus: "?new genus to be erected for ''Bolodon elongatus''," (Kielan-Jaworowska & Hurum, 2001, p. 414). Fossils of the species ''Bolodon minor'' (type species of the ''Plioprion'') have been found in the Lower Cretaceous of Durlston Bay, Dorset. ''Plioprion'' (Cope, 1884) is probably synonymous with ''Bolodon''. The species ''Bolodon osborni'' was named by Simpson G.G. in 1928. Fossils have been found in the Berriasian (Lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together with Saur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camarasaurus
''Camarasaurus'' ( ) was a genus of quadrupedal, herbivorous dinosaurs and is the most common North American sauropod fossil. Its fossil remains have been found in the Morrison Formation, dating to the Late Jurassic epoch (Kimmeridgian to Tithonian stages), between 155 and 145 million years ago. ''Camarasaurus'' presented a distinctive cranial profile of a blunt snout and an arched skull that was remarkably square, typical of basal Macronarians. The name means "chambered lizard", referring to the hollow chambers, known as pleurocoels, in its cervical vertebrae (Greek (') meaning "vaulted chamber", or anything with an arched cover, and (') meaning "lizard". ''Camarasaurus'' contains four species that are commonly recognized as valid: ''Camarasaurus grandis'', '' Camarasaurus lentus'', '' Camarasaurus lewisi'', and ''Camarasaurus supremus''. ''C. supremus'', the type species, is the largest and geologically youngest of the four. ''Camarasaurus'' is the type genus of Camarasau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macronaria
Macronaria is a clade of sauropod dinosaurs. Macronarians are named after the large diameter of the nasal opening of their skull, known as the external naris, which exceeded the size of the orbit, the skull opening where the eye is located (hence ''macro''- meaning large, and –''naria'' meaning nose). Fossil evidence suggests that macronarian dinosaurs lived from the Middle Jurassic (Bathonian) through the Late Cretaceous (Maastrichtian). Macronarians have been found globally, including discoveries in Argentina, the United States, Portugal, China, and Tanzania. Like other sauropods, they are known to have inhabited primarily terrestrial areas, and little evidence exists to suggest that they spent much time in coastal environments. Macronarians are diagnosed through their distinct characters on their skulls, as well as appendicular and vertebral characters. Macronaria is composed of several subclades and families notably including Camarasauridae and Titanosauriformes, among severa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmakasaurus
''Osmakasaurus'' (meaning "canyon lizard", ''ósmaka'' meaning "canyon" in the Lakota language) is a genus of herbivorous iguanodontian dinosaur. It is a basal iguanodontian which lived during the Early Cretaceous period (Valanginian age) in what is now Buffalo Gap of South Dakota, United States. It is known from the Chilson Member of the Lakota Formation. This genus was named by Andrew T. McDonald in 2011 and the type species is ''O. depressus''. Discovery and naming The holotype, USNM 4753, was discovered by Nelson Horatio Darton in 1896 within a layer of the Lakota Formation. The type species ''O. depressus'' was previously referred to as ''Camptosaurus ''Camptosaurus'' ( ) is a genus of plant-eating, beaked ornithischian dinosaurs of the Late Jurassic period of western North America and possibly also Europe. The name means 'flexible lizard' ( Greek (') meaning 'bent' and (') meaning 'li ... depressus'', and was first described in 1909 by Charles W. Gilmore. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polacanthidae
Polacanthinae is a subfamily of ankylosaurs, most often nodosaurids, from the Late Jurassic through Early Cretaceous of Europe and potentially North America and Asia. The group is defined as the largest clade closer to ''Polacanthus foxii'' than '' Nodosaurus textilis'' or ''Ankylosaurus magniventris'', as long as that group nests within either Nodosauridae or Ankylosauridae. If ''Polacanthus'', and by extent Polacanthinae, falls outside either family-level clade, then the ''-inae'' suffix would be inappropriate, and the proper name for the group would be the informally defined Polacanthidae. Polacanthines were somewhat more lightly armoured than more advanced ankylosaurids and nodosaurids. Their spikes were made up of thin, compact bone with less reinforcing collagen than in the heavily armoured nodosaurids. The relative fragility of polacanthine armour suggests that it may have been as much for display as defense. They appear to have become extinct about the same time a land bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
