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Bullhead Shark
The bullhead sharks are a small order (Heterodontiformes ) of modern sharks (Neoselachii). The nine living species are placed in a single genus, ''Heterodontus'', in the family Heterodontidae. All are relatively small, with the largest species reaching just in maximum length. They are bottom feeders in tropical and subtropical waters. The Heterodontiforms appear in the fossil record in the Early Jurassic, well before any of the other Galeomorphii, a group that includes all modern sharks except the dogfish and its relatives. However, they have never been common, and their origin probably lies even further back. Description The bullhead sharks are morphologically rather distinctive. The mouth is located entirely anterior to the orbits. Labial cartilages are found in the most anterior part of the mouth. Nasoral grooves are present, connecting the external nares to the mouth. The nasal capsules are trumpet-shaped and well-separated from orbits. Circumnarial skin folds are pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian. The Toarcian Age began with the Toarcian turnover, the extinction event that sets its fossil faunas apart from the previous Pliensbachian age. It is believed to have ended with a global cooling event known as the Comptum Cooling Event, although whether it represented a worldwide event is controversial. Stratigraphic definitions The Toarcian takes its name from the city of Thouars, just south of Saumur in the Loire Valley of France. The stage was introduced by French palaeontologist Alcide d'Orbigny in 1842, after examining rock strata of this age in a quarry near Thouars. In Europe this period is represented by the upper part of the Lias. The base of the Toarcian is defined as the place in the stratigraphic record where the ammonite genus '' E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supraorbital Crest
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Supraorbital refers to the region immediately above the eye sockets, where in humans the eyebrows are located. It denotes several anatomical features, such as: *Supraorbital artery *Supraorbital foramen * Supraorbital gland *Supraorbital nerve *Supraorbital ridge *Supraorbital vein The supraorbital vein is a vein of the forehead. It communicates with the frontal branch of the superficial temporal vein. It passes through the supraorbital notch, and merges with the angular vein to form the superior ophthalmic vein. The sup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William John Macleay
Sir William John Macleay (13 June 1820 – 7 December 1891) was a Scottish- Australian politician, naturalist, zoologist, and herpetologist. Early life Macleay was born at Wick, Caithness, Scotland, second son of Kenneth Macleay of Keiss and his wife Barbara, ''née'' Horne. Macleay was educated at the Edinburgh Academy 1834–36 and then to studied medicine at the University of Edinburgh; but when he was 18 years old his widowed mother died, and he decided to go to Australia with his cousin, William Sharp MacLeay. They arrived at Sydney in March 1839 on HMS ''Royal George''. William Macleay took up land at first near Goulburn, and afterwards on the Murrumbidgee River. He is noted as the last of the naturalists in a family active in this field; his uncle was Alexander Macleay, Colonial Secretary of New South Wales from 1826 to 1836, and a member and fellow of societies concerned with the flora and fauna of the empire's colonies. Political career On 1 March 1855 Macleay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicholas Miklouho-Maclay
Nicholas Miklouho-Maclay (russian: Никола́й Никола́евич Миклу́хо-Макла́й; 1846 – 1888) was a Russian Imperial explorer. He worked as an ethnologist, anthropologist and biologist who became famous as one of the earliest scientists to settle among and study indigenous people of New Guinea who had never seen a European.Webster, E. M. (1984). ''The Moon Man: A Biography of Nikolai Miklouho-Maclay''. University of California Press, Berkeley. 421 pages. Miklouho-Maclay spent the major part of his life travelling and conducted scientific research in the Middle East, Australia, New Guinea, Melanesia and Polynesia. Australia became his adopted country and Sydney the hometown of his family.Wongar, B., Commentary and Translator's Note in Miklouho-Maclay, N. N. ''The New Guinea Diaries 1871-1183'', translated by B. Wonger, Dingo Books, Victoria, Australia [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Bullhead Shark
The Japanese bullhead shark (''Heterodontus japonicus'') is a species of bullhead shark in the family Heterodontidae found in the northwestern Pacific Ocean off the coasts of Japan, Korea, and China. This benthic shark occurs at depths of over rocky bottoms or kelp beds. Measuring up to long, it can be identified by its short, blunt head, two high dorsal fins with anterior spines, and pattern of irregularly shaped, vertical brown bands and stripes. The Japanese bullhead shark is a docile, slow-swimming species that feeds mainly on shelled invertebrates and small bony fishes. Reproduction is oviparous, with females laying spiral-flanged eggs in communal "nests". This species is of little interest to fisheries. Taxonomy The Japanese bullhead shark was originally described as ''Cestracion japonicus'' by ichthyologists Nicholas Miklouho-Maclay and William John Macleay, in an 1884 volume of ''Proceedings of the Linnean Society of New South Wales''. The type specimen is a female cau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Günther
Albert Karl Ludwig Gotthilf Günther FRS, also Albert Charles Lewis Gotthilf Günther (3 October 1830 – 1 February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile taxonomist (after George Albert Boulenger) with more than 340 reptile species described. Early life and career Günther was born in Esslingen in Swabia (Württemberg). His father was a ''Stiftungs-Commissar'' in Esslingen and his mother was Eleonora Nagel. He initially schooled at the Stuttgart Gymnasium. His family wished him to train for the ministry of the Lutheran Church for which he moved to the University of Tübingen. A brother shifted from theology to medicine, and he, too, turned to science and medicine at Tübingen in 1852. His first work was "''Ueber den Puppenzustand eines Distoma''". He graduated in medicine with an M.D. from Tübingen in 1858, the same year in which he published a handbook of zoology for students of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crested Bullhead Shark
The crested bullhead shark (''Heterodontus galeatus'') is an uncommon species of bullhead shark, in the family Heterodontidae. It lives off the coast of eastern Australia from the coast to a depth of . This shark can be distinguished from other members of its family by the large size of the ridges above its eyes and by its color pattern of large dark blotches. It typically attains a length of . Nocturnal and bottom-dwelling, the crested bullhead shark favors rocky reefs and vegetated areas, where it hunts for sea urchins and other small organisms. It is oviparous, with females producing spiral-shaped egg capsules that are secured to seaweed or sponges with long tendrils. Sexual maturation is slow, with one female in captivity not laying eggs until almost 12 years of age. The International Union for Conservation of Nature has assessed this harmless shark as of Least Concern; it is of no economic interest and suffers minimal mortality from bycatch, recreational fishing, and shar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Frédéric Girard
Charles Frédéric Girard (8 March 1822 – 29 January 1895) was a French biologist specializing in ichthyology and herpetology. Born in Mulhouse, France, he studied at the College of Neuchâtel, Switzerland, as a student of Louis Agassiz. In 1847, he accompanied Agassiz as his assistant to Harvard University. Three years later, Spencer Fullerton Baird called him to the Smithsonian Institution to work on its growing collection of North American reptiles, amphibians and fishes. He worked at the museum for the next ten years and published numerous papers, many in collaboration with Baird. In 1854, he was naturalized as a U.S. citizen. Besides his work at the Smithsonian, he managed to earn an M.D. from Georgetown University in Washington, D.C. in 1856. In 1859 he returned to France and was awarded the Cuvier Prize by the Institute of France for his work on the North American reptiles and fishes two years later. When the American Civil War broke out, he joined the Confeder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartilage
Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck and the bronchial tubes, and the intervertebral discs. In other taxa, such as chondrichthyans, but also in cyclostomes, it may constitute a much greater proportion of the skeleton. It is not as hard and rigid as bone, but it is much stiffer and much less flexible than muscle. The matrix of cartilage is made up of glycosaminoglycans, proteoglycans, collagen fibers and, sometimes, elastin. Because of its rigidity, cartilage often serves the purpose of holding tubes open in the body. Examples include the rings of the trachea, such as the cricoid cartilage and carina. Cartilage is composed of specialized cells called chondrocytes that produce a large amount of collagenous extracellular matrix, abundant ground substance that is rich in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anal Fin
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. Apart from the tail or caudal fin, fish fins have no direct connection with the spine and are supported only by muscles. Their principal function is to help the fish swim. Fins located in different places on the fish serve different purposes such as moving forward, turning, keeping an upright position or stopping. Most fish use fins when swimming, flying fish use pectoral fins for gliding, and frogfish use them for crawling. Fins can also be used for other purposes; male sharks and mosquitofish use a modified fin to deliver sperm, thresher sharks use their caudal fin to stun prey, reef stonefish have spines in their dorsal fins that inject venom, anglerfish use the first spine of their dorsal fin like a fishing rod to lu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Fin
A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through convergent evolution they have independently evolved external superficial fish-like body plans adapted to their marine environments, including most numerously fish, but also mammals such as cetaceans ( whales, dolphins, and porpoises), and even extinct ancient marine reptiles such as various known species of ichthyosaurs. Most species have only one dorsal fin, but some have two or three. Wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of large cetaceans to identify individuals in the field. The bony or cartilaginous bones that support the base of the dorsal fin in fish are called ''pterygiophores''. Functions The main purpose of the dorsal fin is to stabilize the animal against ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamniformes
The Lamniformes (, from Greek ''lamna'' "fish of prey") are an order of sharks commonly known as mackerel sharks (which may also refer specifically to the family Lamnidae). It includes some of the most familiar species of sharks, such as the great white, as well as more unusual representatives, such as the goblin shark and megamouth shark. Members of the order are distinguished by possessing two dorsal fins, an anal fin, five gill slits, eyes without nictitating membranes, and a mouth extending behind the eyes. Species in two families of Lamniformes – Lamnidae and Alopiidae – are distinguished for maintaining a higher body temperature than the surrounding water. Members of the group include macropredators, generally of medium-large size, including the largest macropredatory shark ever, the extinct '' Otodus megalodon,'' as well as large planktivores. The oldest member of the group is the small (~ long) carpet shark-like ''Palaeocarcharias,'' known from the Middle and Lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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