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Malawania Anachronus
''Malawania'' is an extinct genus of basal thunnosaur ichthyosaur known from the middle Early Cretaceous (Hauterivian or Barremian stage) of Iraq. ''Malawania'' was named by Valentin Fischer, Robert M. Appleby, Darren Naish, Jeff Liston, Riding, J. B., Brindley, S. and Pascal Godefroit in 2013 and the type species is ''Malawania anachronus''. It is unusual as it is much more primitive than other Cretaceous ichthyosaurs, being most closely related to '' Ichthyosaurus'' from the Late Triassic and Early Jurassic, over 70 million years earlier than ''Malawania'', with all other known ichthyosaurs from the Late Jurassic onwards belonging to the family Ophthalmosauridae. Discovery The holotype and only known specimen was discovered in 1952 by British petroleum geologists D. M. Morton, F. R. S. Henson, R. J. Wetzel and L. C. F. Damesin while working in Chia Gara, Amadia in Iraqi Kurdistan. The slab was being used to dam a small river and was part of a mule track. It was then trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronological name) or the Lower Cretaceous ( chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian-Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining early Aptian Oceanic Anoxic Event 1a (OAE1a) was carbon isotope dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java- Manihiki- Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Ontong Java Plateau today covers an area of 1,860,000 km2. In the Indian Ocean another LIP began to form at c. 120 Ma, the Kergue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iraqi Kurdistan
Iraqi Kurdistan or Southern Kurdistan ( ku, باشووری کوردستان, Başûrê Kurdistanê) refers to the Kurdish-populated part of northern Iraq. It is considered one of the four parts of "Kurdistan" in Western Asia, which also includes parts of southeastern Turkey (Northern Kurdistan), northern Syria (Western Kurdistan), and northwestern Iran (Eastern Kurdistan). Much of the geographical and cultural region of Iraqi Kurdistan is part of the Kurdistan Region (KRI), an autonomous region recognized by the Constitution of Iraq. As with the rest of Kurdistan, and unlike most of the rest of Iraq, the region is inland and mountainous. Etymology The exact origins of the name ''Kurd'' are unclear. The suffix ''-stan'' is an Iranian term for region. The literal translation for Kurdistan is "Region of Kurds". The name was also formerly spelled ''Curdistan''. One of the ancient names of Kurdistan is ''Corduene''.A.D. Lee, ''The Role of Hostages in Roman Diplomacy with Sas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neural Spines
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the backbone), and on the other with phylogenetic differences among the vertebrate taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch (in ... [...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 vertebrae and they are intermediate in size between the cervical and lumbar vertebrae; they increase in size going towards the lumbar vertebrae, with the lower ones being much larger than the upper. They are distinguished by the presence of facets on the sides of the bodies for articulation with the heads of the ribs, as well as facets on the transverse processes of all, except the eleventh and twelfth, for articulation with the 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 vertebrae contain certai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlas Bone
In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck. It is named for Atlas of Greek mythology because, just as Atlas supported the globe, it supports the entire head. The atlas is the topmost vertebra and, with the axis (the vertebra below it), forms the joint connecting the skull and spine. The atlas and axis are specialized to allow a greater range of motion than normal vertebrae. They are responsible for the nodding and rotation movements of the head. The atlanto-occipital joint allows the head to nod up and down on the vertebral column. The dens acts as a pivot that allows the atlas and attached head to rotate on the axis, side to side. The atlas's chief peculiarity is that it has no body. It is ring-like and consists of an anterior and a posterior arch and two lateral masses. The atlas and axis are important neurologically because the brainstem extends down to the axis. Structure Anterior arch The anter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centra (anatomy)
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the backbone), and on the other with phylogenetic differences among the vertebrate taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral arch ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cervical Vertebrae
In tetrapods, cervical vertebrae (singular: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In sauropsid species, the cervical vertebrae bear cervical ribs. In lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The vertebral transverse processes of mammals are homologous to the cervical ribs of other amniotes. Most mammals have seven cervical vertebrae, with the only three known exceptions being the manatee with six, the two-toed sloth with five or six, and the three-toed sloth with nine. In humans, cervical vertebrae are the smallest of the true vertebrae and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process, through which the vertebral artery, vertebral veins, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclerotic Rings
Sclerotic rings are rings of bone found in the eyes of many animals in several groups of vertebrates, except for mammals and crocodilians. They can be made up of single bones or multiple segments and take their name from the sclera. They are believed to have a role in supporting the eye, especially in animals whose eyes are not spherical, or which live underwater. Fossil sclerotic rings are known for a variety of extinct animals, including ichthyosaurs, pterosaurs, and dinosaurs, but are often not preserved. File:Tawny Frogmouth Skull.jpg, A skull of an extant tawny frogmouth, showing large sclerotic rings. File:Uroplatus_phantasticus_skull1.jpg, A skull of an extant satanic leaf-tailed gecko, showing large sclerotic rings. File:Viatkogorgon skull.png, Skull and sclerotic ring of the gorgonopsian ''Viatkogorgon''. File:Prosaurolophus maximus3.JPG, Sclerotic ring of the hadrosaur ''Prosaurolophus ''Prosaurolophus'' (; meaning "before ''Saurolophus''", in comparison to the lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tear Film
Tears are a clear liquid secreted by the lacrimal glands (tear gland) found in the eyes of all land mammals. Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes. The different types of tears—basal, reflex, and emotional—vary significantly in composition. The functions of tears include lubricating the eyes (basal tears), removing irritants (reflex tears), and also aiding the immune system. Tears also occur as a part of the body's natural pain response. Emotional secretion of tears may serve a biological function by excreting stress-inducing hormones built up through times of emotional distress. Tears have symbolic significance among humans. Physiology Chemical composition Tears are made up of three layers: lipid, aqueous, and mucous. Tears are composed of water, salts, antibodies, and lysozymes (antibacterial enzymes); though composition varies among different tear types. The composition of tears caused by an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Glands
The lacrimal glands are paired exocrine glands, one for each eye, found in most terrestrial vertebrates and some marine mammals, that secrete the aqueous layer of the tear film. In humans, they are situated in the upper lateral region of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. Inflammation of the lacrimal glands is called dacryoadenitis. The lacrimal gland produces tears which are secreted by the lacrimal ducts, and flow over the ocular surface, and then into canals that connect to the lacrimal sac. From that sac, the tears drain through the lacrimal duct into the nose. Anatomists divide the gland into two sections, a palpebral lobe, or portion, and an orbital lobe or portion. The smaller ''palpebral lobe'' lies close to the eye, along the inner surface of the eyelid; if the upper eyelid is everted, the palpebral portion can be seen. The orbital lobe of the gland, contains fine interlobular ducts that connect the orbital lobe and the palpebral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , of which the eye occupies . The orbital contents comprise the eye, the orbital and retrobulbar fascia, extraocular muscles, cranial nerves II, III, IV, V, and VI, blood vessels, fat, the lacrimal gland with its sac and duct, the eyelids, medial and lateral palpebral ligaments, cheek ligaments, the suspensory ligament, septum, ciliary ganglion and short ciliary nerves. Structure The orbits are conical or four-sided pyramidal cavities, which open into the midline of the face and point back into the head. Each consists of a base, an apex and four walls."eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009 Openings There are two important foramina, or windows, two important f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Bone
The lacrimal bone is a small and fragile bone of the facial skeleton; it is roughly the size of the little fingernail. It is situated at the front part of the medial wall of the orbit. It has two surfaces and four borders. Several bony landmarks of the lacrimal bone function in the process of lacrimation or crying. Specifically, the lacrimal bone helps form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of the bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears or lacrimal fluid, from the lacrimal glands, collect in this sac during excessive lacrimation. The fluid then flows through the nasolacrimal duct and into the nasopharynx. This drainage results in what is commonly referred to a runny nose during excessive crying or tear production. Injury or fracture of the lacrimal bone can result in posttraumatic obstruction of the lacrimal pathways. Structure Lateral or orbital surface The lateral or orbital surface i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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