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Zapatadon
''Zapatadon'' is an extinct genus of sphenodontid reptile from the end of the Early Jurassic in the lower part of La Boca Formation of Tamaulipas, Mexico.Marisol Montellano, James A. Hopson and James M. Clark (2008)Late Early Jurassic Mammaliaforms from Huizachal Canyon, Tamaulipas, México ''Journal of Vertebrate Paleontology'', Vol. 28, No. 4 (Dec. 12, 2008), pp. 1130-1143. Is known from a nearly complete skull with mandible of a post-hatchling individual (the specimen IGM 3497, in the Instituto de Geologia, of the Universidad Nacional Autónoma de Mexico), and is one of the smallest skulls between the sphenodontians, with an estimated total length of 11.3 millimetres, a bit smaller than the hatchling individuals observed in the modern tuatara (''Sphenodon''); features like the oblique mandibular symphysis suggests that the holotype is from an individual in a relatively mature stage of ontogenic development. ''Zapatadon'' is diagnosed by their hatchling tooth series located in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
La Boca Formation
The La Boca Formation is a geological formation in Tamaulipas state, northeast Mexico. It was thought to date back to the Early Jurassic, concretely the Pliensbachian stage epoch. Although, the latest studies had proven that the local Vulcanism, related to the aperture of the Atlantic Ocean and the several Rift Events, that continue until the Bajocian, while the unit itself was likely deposited between the earliest Pliensbachian, as proven by zircon (189.0 ± 0.2 Ma) with the fossil taxa deposited on the rocks above, likely of Late Pliensbachian-Lower Toarcian age, and the upper section of Late Toarcian-Late Aalenian age. Due to successions of Aalenian depositional sistems on the upper layers of the Huizachal Canyon, has been delimited the formation to the Toarcian stage, being the regional equivalent of the Moroccan Azilal Formation. In North America, ''La Boca Formation'' was found to be a regional equivalent of the Eagle Mills redbeds of southern United States, the Todos Santos F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.1 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias limestone from S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jugal
The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anatomy The jugal bone is located on either side of the skull in the circumorbital region. It is the origin of several masticatory muscles in the skull. The jugal and lacrimal bones are the only two remaining from the ancestral circumorbital series: the prefrontal, postfrontal, postorbital, jugal, and lacrimal bones. During development, the jugal bone originates from dermal bone. In dinosaurs This bone is considered key in the determination of general traits in cases in which the entire skull has not been found intact (for instance, as with dinosaurs in paleontology). In some dinosaur genera the jugal also forms part of the lower margin of either the antorbital fenestra or the infratemporal fenestra, or both. Most commonly, this bone articu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammaliaforms
Mammaliaformes ("mammalian forms") is a clade that contains the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts. It is defined as the clade originating from the most recent common ancestor of Morganucodonta and the crown group mammals; the latter is the clade originating with the most recent common ancestor of extant Monotremata, Marsupialia, and Placentalia. Besides Morganucodonta and the crown group mammals, Mammaliaformes includes Docodonta and '' Hadrocodium'' as well as the Triassic '' Tikitherium'', the earliest known member of the group. Mammaliaformes is a term of phylogenetic nomenclature. In contrast, the assignment of organisms to Mammalia has traditionally been founded on traits and, on this basis, Mammalia is slightly more inclusive than Mammaliaformes. In particular, trait-based taxonomy generally includes ''Adelobasileus'' and ''Sinoconodon'' in Mammalia, though they fall outside the Mam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bocatherium
''Bocatherium'' is an extinct genus of tritylodonts from the Pliensbachian (Early Jurassic) of Tamaulipas, Mexico. It is known only from a skull found at the Huizachal Canyon locality, "a Pliensbachian floodplain siltstone in the La Boca Formation The La Boca Formation is a geological formation in Tamaulipas state, northeast Mexico. It was thought to date back to the Early Jurassic, concretely the Pliensbachian stage epoch. Although, the latest studies had proven that the local Vulcanism, r ...". References Jurassic synapsids Prehistoric cynodont genera Fossils of Mexico Tritylodontids Fossil taxa described in 1985 {{Paleo-Therapsid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tritylodont
Tritylodontidae ("three-knob teeth", named after the shape of their cheek teeth) is an extinct family of small to medium-sized, highly specialized mammal-like cynodonts, bearing several mammalian traits like erect limbs, endothermy and details of the skeleton. They were the last-known family of the non-mammaliaform synapsids, persisting into the Early Cretaceous. Most tritylodontids are thought to have been herbivorous, feeding on vegetation, such as stems, leaves, and roots, although at least one may have had a more omnivorous diet. Tritylodontid fossils are found in the Americas, South Africa, and Eurasia—they appear to have had an almost global distribution, including Antarctica. Description The skull of tritylodontids had a high sagittal crest. They retained the primitive condition of the joint between the quadrate bone of the skull and the articular bone of the lower jaw—the retention of the joint is one of the reasons they are technically regarded to not be mammals, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimorphodon
''Dimorphodon'' was a genus of medium-sized pterosaur from the early Jurassic Period. It was named by paleontologist Richard Owen in 1859. ''Dimorphodon'' means "two-form tooth", derived from the Greek (') meaning "two", (') meaning "shape" and (') meaning "tooth", referring to the fact that it had two distinct types of teeth in its jaws – which is comparatively rare among reptiles. ''Dimorphodon'' inhabited Europe. Description The body structure of ''Dimorphodon'' displays many "primitive" characteristics, such as, according to Owen, a very small brain-pan and proportionally short wings. The first phalanx in its flight finger is only slightly longer than its lower arm. The neck was short but strong and flexible and may have had a membranous pouch on the underside. The vertebrae had pneumatic foramina, openings through which the air sacs could reach the hollow interior. ''Dimorphodon'' had an adult body length of long, with a 1.45 metre (4.6 ft) wingspan. The tai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tamaulipasaurus
''Tamaulipasaurus'' is an extinct genus of lepidosauromorph reptile from the Early Jurassic of Mexico. It contains a single species, ''Tamaulipasaurus morenoi'', which is based on skull material found at Huizachal Canyon, a productive fossil site in the La Boca Formation.R. C. Munter and J. M. Clark. 2006. Theropod dinosaurs from the Early Jurassic of Huizachal Canyon, Mexico. In M. T. Carrano, T. J. Gaudin, R. W. Blob, J. R. Wible (eds.), Amniote paleobiology: perspectives on the evolution of mammals, birds, and reptiles. University of Chicago Press, Chicago 53-7 ''Tamaulipasaurus'' had an unusual condensed skull similar to that of amphisbaenians, a modern group of burrowing squamates. It also possessed a variety of plesiomorphic In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and ... (" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenovipera
''Sphenovipera jimmysjoyi'' is an extinct species of sphenodontian dated from the Middle Jurassic. If was discovered in the lower part of the La Boca Formation located in Tamaulipas, Mexico. Only the lower jaw of this organism has been discovered and studied. It is possibly the only species of rhynchocephalian yet discovered to show evidence of venom delivery. Etymology ''Sphenovipera'' was named by Reynoso in 2005. The name alludes to sphenodontians via ''Spheno-'' and ''-vipera'' is Latin for "venomous snake." Venom delivery The mandible of ''Sphenovipera jimmysjoyi'' has several characteristics indicative of venom delivery. This includes large curved fangs with grooves seen in other animals that use low-pressure venom delivery, such as colubrid snakes Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynosphenodon
''Cynosphenodon'' ( ; "Dog Sphenodontian") is an extinct genus of the family Sphenodontidae from the Middle Jurassic La Boca Formation of Tamaulipas, Mexico. Growth patterns in the teeth of ''Cynosphenodon'' suggest its close relationship with the modern tuatara Tuatara (''Sphenodon punctatus'') are reptiles endemic to New Zealand. Despite their close resemblance to lizards, they are part of a distinct lineage, the order Rhynchocephalia. The name ''tuatara'' is derived from the Māori language and m ....Reynoso, V. H. (2003). Growth patterns and ontogenetic variation of the teeth and jaws of the Middle Jurassic sphenodontian ''Cynosphenodon huizachalensis'' (Reptilia: Rhynchocephalia). ''Canadian Journal of Earth Sciences 40''(4), 609–619 References Jurassic lepidosaurs Sphenodontia Fossils of Mexico Prehistoric reptile genera {{Jurassic-reptile-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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