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Mission Valley Formation
The Mission Valley Formation is a marine sandstone geologic formation in the Mission Valley region of southwestern San Diego County in Southern California. Geology The formation's sandstone characteristics are: soft and friable, light olive gray, fine to medium grained, and composed mostly of quartz and potassium feldspar. The Mission Valley Formation thins from the west to the east, with a maximum thickness of . It overlies the Stadium Conglomerate formation and underlies the Pomerado Conglomerate formation. Fossil content It preserves fossils dating back to the Paleogene period of the Cenozoic Era. The formation's rocks can contain a molluscan fauna in the western and central exposures and a land-mammal fauna in the eastern exposures. Mammals Eulipotyphlans Ferae Primatomorphs See also * * * List of fossiliferous stratigraphic units in California * Paleontology in California Paleontology in California refers to paleontologist research occurring within or conduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic 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] |
Astragalus Bone
The talus (; Latin for ankle or ankle bone), talus bone, astragalus (), or ankle bone is one of the group of foot bones known as the tarsus. The tarsus forms the lower part of the ankle joint. It transmits the entire weight of the body from the lower legs to the foot.Platzer (2004), p 216 The talus has joints with the two bones of the lower leg, the tibia and thinner fibula. These leg bones have two prominences (the lateral and medial malleoli) that articulate with the talus. At the foot end, within the tarsus, the talus articulates with the calcaneus (heel bone) below, and with the curved navicular bone in front; together, these foot articulations form the ball-and-socket-shaped talocalcaneonavicular joint. The talus is the second largest of the tarsal bones; it is also one of the bones in the human body with the highest percentage of its surface area covered by articular cartilage. It is also unusual in that it has a retrograde blood supply, i.e. arterial blood enters th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friars Formation
The Friars Formation is a geologic formation in San Diego County, Southern California. Geology It is the uppermost unit of the La Jolla Group. The rocks are nonmarine and lagoonal sandstone and claystone, named for exposures along the north side of Mission Valley near Friars Road. It reaches a maximum thickness of between Mission Valley and Carmel Valley. Fossils It preserves fossils dating back to the middle and late Eocene epoch of the Paleogene period, during the Cenozoic Era. See also * * * List of fossiliferous stratigraphic units in California This article contains a list of fossil-bearing stratigraphic units in the state of California, U.S. Sites See also * Paleontology in California References * {{DEFAULTSORT:Fossiliferous stratigraphic units in California California S ... * Paleontology in California References Further reading * Geologic formations of California Paleogene California Eocene Series of North America Geology of S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Omomyidae
Omomyidae is a group of early primates that radiated during the Eocene epoch between about (mya). Fossil omomyids are found in North America, Europe & Asia making it one of two groups of Eocene primates with a geographic distribution spanning holarctic continents, the other being the adapids (family Adapidae). Early representatives of the Omomyidae and Adapidae appear suddenly at the beginning of the Eocene (56 mya) in North America, Europe, and Asia, and are the earliest known crown primates. Etymology The Omomyidae are named after the type genus '' Omomys''. While the etymology of this genus is uncertain, it most likely derives from the Ancient Greek ὠμός (ōmós), "raw, crude" + μῦς (mûs), "mouse". Characteristics Features that characterize many omomyids include large orbits (eye sockets), shortened rostra and dental arcades, loss of anterior premolars, cheek teeth adapted for insectivorous or frugivorous diets, and relatively small body mass (i.e., less th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primatomorph
The Primatomorpha are a proposed mirorder of mammals containing the flying lemurs (order Dermoptera or colugos) and lemurs (Strepsirrhini, adapiformes and lemuriformes). However, notably, the haplorhini are sister to the lemurs, together forming the primate (Plesiadapiformes and descendents) order within this group. Primatomorpha is sister to Scandentia, together forming the Euarchonta. The term "Primatomorpha" first appeared in the general scientific literature in 1991 (K.C. Beard) and 1992 (Kalandadze, Rautian). Major DNA sequence analyses of predominantly nuclear sequences (Murphy et al., 2001) support the Euarchonta hypothesis, while a major study investigating mitochondrial sequences supports a different tree topology (Arnason et al., 2002). A study investigating retrotransposon presence/absence data has claimed strong support for Euarchonta (Kriegs et al., 2007). Some interpretations of the molecular data link Primates and Dermoptera in a clade A clade (), al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procynodictis
''Procynodictis'' ("before '' Cynodictis''") is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America from the early to middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ....J. J. Flynn (1998.) "Early Cenozoic Carnivora ("Miacoidea")." In C. M. Janis, K. M. Scott, and L. L. Jacobs (''eds.''"Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals."Cambridge University Press, Cambridge. References Miacids Eocene mammals of North America Carnivoraformes {{Paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miacidae
Miacids are extinct primitive carnivoramorphans within the family Miacidae that lived during the Paleocene and Eocene epochs, about 62–34 million years ago. Miacids existed for approximately . Miacids are thought to have evolved into the modern carnivorous mammals of the order Carnivora. They were small carnivores, superficially marten-like or civet-like with long, lithe bodies and long tails. Some species were arboreal, while others lived on the ground. They probably fed on invertebrates, lizards, birds, and smaller mammals like shrews and opossums. Their teeth and skulls show that the miacids were less developed than modern carnivorans. They had carnivoran-type carnassials, but lacked fully ossified auditory bullae (rounded protrusions). Classification Miacidae as traditionally conceived is not a monophyletic group; it is a paraphyletic array of stem taxa. Traditionally, Miacidae and Viverravidae had been classified in a superfamily, Miacoidea. Today, Carnivora a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dentary
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear). It is connected to the temporal bones by the temporomandibular joints. The bone is formed prenatal development, in the fetus from a fusion of the left and right mandibular prominences, and the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, p. 59 The word "mandible" derives from the Latin word ''mandibula'', "jawbone" (literally "one used for chewing"), from ''wikt:mandere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miacis
''Miacis'' is a genus of extinct carnivorous mammals that appeared in the late Paleocene and continued through the Eocene. The genus ''Miacis'' is not monophyletic but a diverse collection of species that belong to the stemgroup within the Carnivoramorpha.Wesley-Hunt, G.D.; Flynn J.J. (2005). Phylogeny of the Carnivora: Basal Relationships Among the Carnivoramorphans, and Assessment of the Position of 'Miacoidea' Relative to Carnivora. ''Journal of Systematic Palaeontology'', 3: 1-28. As such, most ''Miacis'' species belong to the group of early carnivores that represent the ancestors of the modern order, the crown-group Carnivora. However, the species ''Miacis cognitus'' (now ''Gustafsonia'') is placed not in the stem-group but among the Caniformia,Spaulding, M.; Flynn J.J.; Stucky, R.K. (2010) Anew basal Carnivoramorphan (Mammalia) from the ‘Bridger B’ (Black’s Fork Member, Bridger Formation, Bridgerian NALMA, Middel Eocene) of Wyoming, USA. ''Paleontology'' 53: 81 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivoraformes
Carnivoraformes ("carnivoran-like forms") is a clade of placental mammals that includes the modern order Carnivora and its extinct stem-relatives. Classification and phylogeny Classification In 2010 Flynn, Finarelli & Spaulding named a new clade Carnivoraformes within Carnivoramorpha, containing carnivorans and "miacids" but not viverravids. The authors defined Carnivoraformes as the clade containing Carnivora and all taxa that are more closely related to Carnivora (represented by ''Canis lupus'') than to viverravids (represented by '' Viverravus gracilis''). * ''Clade'': Carnivoraformes ** Order: Carnivora (carnivorans) *** Suborder: Caniformia ("dog-like" carnivorans) *** Suborder: Feliformia ("cat-like" carnivorans) ** Family: † Quercygalidae ** (unranked): †''Gracilocyon''/''Oodectes'' clade *** Genus: †'' Eogale'' *** Genus: †''Gracilocyon''(paraphyletic genus) *** Genus: †''Oodectes''(paraphyletic genus) *** Genus: †''Paramiacis'' *** Genus: †''Paroode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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