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Tika Giacchinoi
''Tika'' is an extinct genus of sphenodontian from the Late Cretaceous Candeleros Formation of Argentina. The type species is ''Tika giacchinoi''. It is considered to be closely related to the tuatara, (''Sphenodon punctatus''), and a member of the Sphenodontinae. It is the oldest member of Sphenodontinae known from South America. Description The type specimen consists of a partial skeleton including an incomplete right-lower jaw, and parts of the skull (an incomplete left palatine and a right quadrate), two articulated dorsal vertebrae, an incomplete ulna, as well as a humerus and a femur. Referred material includes two maxillas with associated lower jaws. The skull is estimated to have been around long when complete, making ''Tika'' moderately-sized among sphenodontians. The caniniform tooth at the front of the lower jaw is sharper than that of the tuatara. The maxilla is similar to that of the tuatara in its overall form. The palate has a row of conical teeth, similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent 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, Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Vertebrae
In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae of intermediate size between the cervical and lumbar vertebrae; they increase in size going towards the lumbar vertebrae. They are distinguished by the presence of Zygapophysial joint, facets on the sides of the bodies for Articulation (anatomy), articulation with the head of rib, heads of the ribs, as well as facets on the transverse processes of all, except the eleventh and twelfth, for articulation with the tubercle (rib), tubercles of the ribs. By convention, the human thoracic vertebrae are numbered T1–T12, with the first one (T1) located closest to the skull and the others going down the spine toward the lumbar region. General characteristics These are the general characteristics of the second through eighth thoracic vertebrae. The first and ninth through twelfth v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhynchocephalia
Rhynchocephalia (; ) is an order of lizard-like reptiles that includes only one living species, the tuatara (''Sphenodon punctatus'') of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a speciose group with high morphological and ecological diversity. The oldest record of the group is dated to the Middle Triassic around 238 to 240 million years ago, and they had achieved global distribution by the Early Jurassic. Most rhynchocephalians belong to the group Sphenodontia ('wedge-teeth'). Their closest living relatives are lizards and snakes in the order Squamata, with the two orders being grouped together in the superorder Lepidosauria. Rhynchocephalians are distinguished from squamates by a number of traits, including the retention of rib-like gastralia bones in the belly, as well as most rhynchocephalians having acrodont teeth that are fused to the crests of the jaws (the latter also found among a small number of modern lizard grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Priosphenodon
''Priosphenodon'' is an extinct, large herbiviorous eilenodontine rhynchocephalian known from the mid-Cretaceous (Albian-Turonian) of Argentina. It is one of the largest known sphenodontians. Taxonomy The type species of ''Priosphenodon, P. avelasi'', was described in 2003 from the Late Cretaceous (Cenomanian-Turonian) aged Candeleros Formation of Argentina. In 2014, a second smaller species, ''P. minimus'' was described from the same formation, though from an earlier unit suggested to be Early Cretaceous (Albian) in age. Other authors have disputed the use of the genus ''Priosphenodon'', with some authors treating ''P. avelasi'' and ''P. minimus'' as members of the previously named genus ''Kaikaifilusaurus'' instead. Description With some individuals reaching over in total length, ''Priosphenodon avelasi'' is the largest known terrestrial sphenodontian. The skull is around long. The front of the upper jaw has a large beak-like structure probably formed from fused teeth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kawasphenodon
''Kawasphenodon'' is an extinct genus of sphenodontian reptile, known from the Late Cretaceous and Paleocene of Patagonia in South America. The type species, ''K. expectatus'', was described in 2005 from jaw fragments found in late Campanian aged sediments in the Los Alamitos Formation, the jaw when complete was estimated to be 11 cm long, making it among the largest known sphenodontians. A second species, ''K. peligrensis'', around 1/3 the size of the type species, was described in 2014 also from jaw fragments in early Paleocene (Danian) sediments of the Salamanca Formation, making it the youngest known definitive representative of Rhynchocephalia outside of New Zealand. In the original description, it was found to be a member of Sphenodontidae, in some other subsequent analyses it was found to be a member of Opisthodontia. A 2020 analysis of rhyncocephalian relationships found it to be outside Opisthodontia, and instead a member of the Sphenodontinae as the closest known re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynosphenodon
''Cynosphenodon'' ( ; "Dog Sphenodontian") is an extinct genus of rhynchocephalian in the family Sphenodontidae from the Middle Jurassic La Boca Formation of Tamaulipas, Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar .... It is known from a largely complete lower jaw and fragments of the upper jaw. It is suggested to be among the closest known relatives of the tuatara, with both being placed in the Sphenodontinae, which is supported by among other characters, the growth pattern of the teeth.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 Cladogram after Simoes et al. 2022. Refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytomy
An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree that contains any multifurcations can be described as a multifurcating tree. Soft polytomies vs. hard polytomies Two types of polytomies are recognized, soft and hard polytomies. Soft polytomies are the result of insufficient phylogenetic information: though the lineages diverged at different times – meaning that some of these lineages are closer relatives than others, and the available data does not allow recognition of this. Most polytomies are soft, meaning that they would be resolved into a typical tree of dichotomies if better data were available. In contrast, a hard polytomy represents a true divergence event of three or more lineages. Applications Interpretations for a polytomy depend on the individuals that are represented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxilla
In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible (lower jaw), which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw. Anatomy Structure The maxilla is a paired bone - the two maxillae unite with each other at the intermaxillary suture. The maxilla consists of: * The body of the maxilla: pyramid-shaped; has an orbital, a nasal, an infratemporal, and a facial surface; contains the maxillary sinus. * Four processes: ** the zygomatic process ** the frontal process ** the alveolar process ** the palatine process It has three surfaces: * the anterior, posterior, medial Features of the maxilla include: * t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrate Bone
The quadrate bone is a skull bone in most tetrapods, including amphibians, sauropsids ( reptiles, birds), and early synapsids. In most tetrapods, the quadrate bone connects to the quadratojugal and squamosal bones in the skull, and forms upper part of the jaw joint. The lower jaw articulates at the articular bone, located at the rear end of the lower jaw. The quadrate bone forms the lower jaw articulation in all classes except mammals. Evolutionarily, it is derived from the hindmost part of the primitive cartilaginous upper jaw. Function in reptiles In certain extinct reptiles, the variation and stability of the morphology of the quadrate bone has helped paleontologists in the species-level taxonomy and identification of mosasaur squamates and spinosaurine dinosaurs. In some lizards and dinosaurs, the quadrate is articulated at both ends and movable. In snakes, the quadrate bone has become elongated and very mobile, and contributes greatly to their ability to swallow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and recover. As a species' potential Range (biology), range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxon, Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the Fossil, fossil record) after a period of apparent absence. Over five billion species are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryotes globally, possibly many times more if microorganisms are included. Notable extinct animal species include Dinosaur, non-avian dinosaurs, Machairodontinae, saber-toothed cats, and mammoths. Through evolution, species arise through the process of specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palatine Bone
In anatomy, the palatine bones (; derived from the Latin ''palatum'') are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxilla, they comprise the hard palate. Structure The palatine bones are situated at the back of the nasal cavity between the maxilla and the pterygoid process of the sphenoid bone. They contribute to the walls of three cavities: the floor and lateral walls of the nasal cavity, the roof of the mouth, and the floor of the orbits. They help to form the pterygopalatine and pterygoid fossae, and the inferior orbital fissures. Each palatine bone somewhat resembles the letter L, and consists of a horizontal plate, a perpendicular plate, and three projecting processes—the pyramidal process, which is directed backward and lateral from the junction of the two parts, and the orbital and sphenoidal processes, which surmount the vertical part, and are separated by a deep notch, the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenodontinae
Sphenodontidae is a family within the reptile group Rhynchocephalia, comprising taxa most closely related to the living tuatara (''Sphenodon punctatus''). Historically the taxa included within Sphenodontidae have varied greatly between analyses, and the group has lacked a formal definition. ''Cynosphenodon'' from the Jurassic of Mexico has consistently been recovered as a close relative of the tuatara in most analyses, with the clade containing the two and other very close relatives of the tuatara often called Sphenodontinae. The herbivorous Eilenodontinae, otherwise considered part of Opisthodontia, is considered to be part of this family in many recent studies as the sister group to Sphenodontinae. The earliest sphenodontines are known from the Early Jurassic of North America, with other remains known from the Late Jurassic of Europe, the Late Cretaceous and possibly Paleocene of South America and the Miocene-recent of New Zealand. Sphenodontines are characterised by a complete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
