|
Tutcetus
''Tutcetus'' is an extinct genus of diminutive basilosaurid cetacean from the Bartonian of Egypt. ''Tutcetus'', named after the child pharaoh Tutankhamun, is both one of the oldest known basilosaurids from Africa and the smallest member of the family. It is suggested that the type specimen, a subadult close to maturity, only measured approximately long. The genus is monotypic, only including the species ''T. rayanensis''. History and naming ''Tutcetus'' was first described in August 2023 on the basis of a single specimen, MUVP 501. The specimen consists of an incomplete skull found alongside both mandibles, the hyoid, and some of the first vertebrae of the neck. The remains stem from the Fayum Depression of Egypt, which is well known for its rich record of early whales. More specifically, the bones of ''Tutcetus'' stem from the Sath El-Hadid Formation, which dates to the early Bartonian (ca. 41 mya). The name ''Tutcetus'' is a reference to the pharaoh Tutankhamun, also known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sath El-Hadid Formation
The Sath El-Hadid Formation, translating to "Iron Surface" in Arabic "سطح الحديد", is a geological formation in Egypt characterized by a nummulitic limestone bank containing large and small ''Nummulites''. Introduced into the stratigraphy of the south Fayum area by Iskander in 1943, this formation is significant in the middle Eocene (Bartonian). Stratigraphy and composition The Sath El-Hadid Formation is approximately 25 meters thick and overlays the Midawara Formation. It is prominent in the Wadi El Rayan area, capping many mesas. The base of the formation is marked by a contact between the snow-white Sath El-Hadid limestone and the brown sandy limestone of the Midawara Formation. The upper contact with the El Gharag Formation is indicated by the emergence of brown and light brown shales above the nummulitic limestone. Distinctive features of the Sath El-Hadid Formation include secondary flint concretions at the top and a gradual transition at the lower contact in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basilosaurid
Basilosauridae is a family of extinct cetaceans that lived during the middle to late Eocene. Basilosaurids are known from all continents including Antarctica, and are probably the first fully aquatic cetaceans.Buono M, Fordyce R.E., Marx F.G., Fernández M.S. & Reguero M. (2019). "Eocene Antarctica: a window into the earliest history of modern whales". ''Advances in Polar Science'' 30(3): p. 293-302. doi:10.13679/j.advps.2019.0005 The group is noted to be a paraphyletic assemblage of stem group whales from which the monophyletic Neoceti are derived. Characteristics Basilosaurids ranged in size from and were fairly similar to modern cetaceans in overall body form and function. Some genera tend to show signs of convergent evolution with mosasaurs by having long serpentine body shape, which suggests that this body plan seems to have been rather successful. Basilosaurid forelimbs have broad and fan-shaped scapulae attached to a humerus, radius, and ulna which are flattened in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wadi El Rayan
Wadi El Rayan is a unique nature protectorate in Faiyum Governorate, Egypt, under the supervision of the Ministry of Environmental Affairs (EEAA). History Wadi el Rayan is mentioned in Coptic sources as Pilihēy (), a salt lake west of Kalamoun where Samuel the Confessor liked to rest. Geography The valley of Wadi El-Rayan is an area of , of which are the dominating water body of the Wadi El Rayan lakes. It is located about southwest of Faiyum city and west of the Nile River. The Wadi has been used for man-made lakes from agricultural drainage which has made a reserve of the two separate Wadi El Rayan Lakes. The reserve is composed of a upper lake and a lower lake, with waterfalls between the two. Among the springs, there are three sulphur springs at the southern side of the lower lake, with extensive mobile sand dunes. Wadi El Rayan Waterfalls are considered to be the largest waterfalls in Egypt. At the south and southeast of the springs is Gabal Manqueer Al Rayan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tutankhamun
Tutankhamun or Tutankhamen, (; ), was an Egyptian pharaoh who ruled during the late Eighteenth Dynasty of Egypt, Eighteenth Dynasty of ancient Egypt. Born Tutankhaten, he instituted the restoration of the traditional polytheistic form of ancient Egyptian religion, undoing a previous shift to the religion known as Atenism. Tutankhamun's reign is considered one of the greatest restoration periods in ancient Egyptian history. His endowments and restorations of cults were recorded on what is today known as the Restoration Stela. The cult of the god Amun at Thebes, Egypt, Thebes was restored to prominence, and the royal couple changed their names to "Tutankhamun" and "Ankhesenamun", replacing the -aten suffix. He also moved the royal court from Akhenaten's capital, Amarna, back to Memphis, Egypt, Memphis almost immediately on his accession to the kingship. He reestablished diplomatic relations with the Mitanni and carried out military campaigns in Nubia and the Near East. Tutankh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cusp (anatomy)
A cusp is a pointed, projecting, or elevated feature. In animals, it is usually used to refer to raised points on the crowns of teeth. The concept is also used with regard to the leaflets of the four heart valves. The mitral valve, which has two cusps, is also known as the bicuspid valve, and the tricuspid valve has three cusps. In humans A cusp is an occlusal or incisal eminence on a tooth. Canine teeth, otherwise known as cuspids, each possess a single cusp, while premolars, otherwise known as bicuspids, possess two each. Molars normally possess either four or five cusps. In certain populations the maxillary molars, especially first molars, will possess a fifth cusp situated on the mesiolingual cusp known as the Cusp of Carabelli. One other variation of the upper first premolar is the 'Uto-Aztecan' upper premolar. It is a bulge on the buccal cusp that is only found in Native American Indians, with highest frequencies of occurrence in Arizona. The name is not a d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Each has two surfaces and four borders. Structure There is heavy variation in the structure of the nasal bones, accounting for the differences in sizes and shapes of the nose seen across different people. Angles, shapes, and configurations of both the bone and cartilage are heavily varied between individuals. Broadly, most nasal bones can be categorized as "V-shaped" or "S-shaped" but these are not scientific or medical categorizations. When viewing anatomical drawings of these bones, consider that they are unlikely to be accurate for a majority of people. The two nasal bones are joined at the midline internasal suture and make up the bridge of the nose. Surfaces The ''outer surface'' is concavo-convex from above downward, convex from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxillae
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: * the infr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premaxillae
The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals has been usually termed as the incisive bone. Other terms used for this structure include premaxillary bone or ''os premaxillare'', intermaxillary bone or ''os intermaxillare'', and Goethe's bone. Human anatomy In human anatomy, the premaxilla is referred to as the incisive bone (') and is the part of the maxilla which bears the incisor teeth, and encompasses the anterior nasal spine and alar region. In the nasal cavity, the premaxillary element projects higher than the maxillary element behind. The palatal portion of the premaxilla is a bony plate with a generally transverse orientation. The incisive foramen is bound anteriorly and laterally by the premaxilla and posteriorly by the palatine process of the maxilla. It is formed from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolar
The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in the permanent teeth, permanent set of teeth, making eight premolars total in the mouth. They have at least two Cusp (dentistry), cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie Posterior (anatomy), posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth Anatomical terms of location#Proximal and distal, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tooth Enamel
Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The other major tissues are dentin, cementum, and Pulp (tooth), dental pulp. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. Features Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%),Ross ''et al.'', p. 485 with water and organic material composing the rest.Ten Cate's Oral Histology, Nancy, Elsevier, pp. 70–94 The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed on the tooth while the tooth develops wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deciduous Teeth
Deciduous teeth or primary teeth, also informally known as baby teeth, milk teeth, or temporary teeth,Fehrenbach, MJ and Popowics, T. (2026). ''Illustrated Dental Embryology, Histology, and Anatomy'', 6th edition, Elsevier, page 287–296. are the first set of teeth in the growth and development of humans and other diphyodonts, which include most mammals but not elephants, kangaroos, or manatees, which are polyphyodonts. Deciduous teeth Animal tooth development, develop during the embryonic stage of development and tooth eruption, erupt (break through the gums and become visible in the mouth) during infancy. They are usually lost and replaced by permanent teeth, but in the absence of their permanent replacements, they can remain functional for many years into adulthood. Development Formation Primary teeth start to form during the embryonic phase of human development (biology), human life. The development of primary teeth starts at the sixth week of tooth development as the d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
