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Whitespotted Bullhead Shark
The whitespotted bullhead shark, ''Heterodontus ramalheira'', is a bullhead shark of the family (biology), family Heterodontidae found in the western and northern Indian Ocean between latitudes 22nd parallel north, 22°N to 26th parallel south, 26°S, at depths between 40 and 305 m. It can grow up to a length of 83 cm. Little is known about the whitespotted bullhead shark. It is found on the outer continental shelf and is thought to feed on crabs, based on the gut contents of two specimen. As a member of the genus ''Heterodontus'', it is thought to be oviparous, but Egg case (Chondrichthyes), egg case of this species have never been seen. References * Heterodontidae Fish described in 1949 {{Shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Smith (ichthyologist)
James Leonard Brierley Smith (26 September 1897 – 8 January 1968) was a South African ichthyology, ichthyologist, organic chemist, and university professor. He was the first to identify a taxidermied fish as a coelacanth, at the time thought to be long extinct. Early life Born in Graaff-Reinet, 26 September 1897, Smith was the elder of two sons of Joseph Smith and his wife, Emily Ann Beck. Educated at country schools at Noupoort, De Aar, and Aliwal North, he finally Matriculation in South Africa, matriculated in 1914 from the Diocesan College, Rondebosch. He obtained a Bachelor of Arts degree in chemistry from the University of the Cape of Good Hope in 1916 and a Master of Science degree in chemistry at Stellenbosch University in 1918. Smith went to the United Kingdom, where he received his PhD at Cambridge University in 1922. After returning to South Africa, he became senior lecturer and later an associate professor of organic chemistry at Rhodes University in Grahamstown. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Family (biology)
Family ( la, familia, plural ') is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". What belongs to a family—or if a described family should be recognized at all—are proposed and determined by practicing taxonomists. There are no hard rules for describing or recognizing a family, but in plants, they can be characterized on the basis of both vegetative and reproductive features of plant species. Taxonomists often take different positions about descriptions, and there may be no broad consensus across the scientific community for some time. The publishing of new data and opini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica, depending on the definition in use. Along its core, the Indian Ocean has some large marginal or regional seas such as the Arabian Sea, Laccadive Sea, Bay of Bengal, and Andaman Sea. Etymology The Indian Ocean has been known by its present name since at least 1515 when the Latin form ''Oceanus Orientalis Indicus'' ("Indian Eastern Ocean") is attested, named after Indian subcontinent, India, which projects into it. It was earlier known as the ''Eastern Ocean'', a term that was still in use during the mid-18th century (see map), as opposed to the ''Western Ocean'' (Atlantic Ocean, Atlantic) before the Pacific Ocean, Pacific was surmised. Conversely, Ming treasure voyages, Chinese explorers in the Indian Oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
22nd Parallel North
The 22nd parallel north is a circle of latitude that is 22 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Indian Ocean, the Pacific Ocean, North America, the Caribbean and the Atlantic Ocean. The majority of the border between Egypt and Sudan follows the parallel. At this latitude the sun is visible for 13 hours, 29 minutes during the summer solstice and 10 hours, 47 minutes during the winter solstice. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 22° north passes through: : See also *21st parallel north *23rd parallel north The 23rd parallel north is a circle of latitude that is 23 degrees north of the Earth's equatorial plane, about south of the Tropic of Cancer. It crosses Africa, Asia, the Indian Ocean, the Pacific Ocean, North America, the Caribbean and the ... References {{geographical coordinates, state=collapsed n22 Egypt–Sudan border ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
26th Parallel South
The 26th parallel south latitude is a circle of latitude that is 26 degrees south of Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Australia, the Pacific Ocean and South America. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 26° south passes through: : Australia In Australia, the northernmost border of South Australia, and the southernmost border of the Northern Territory are defined by 26° south. Additionally, 26° south also defines an approximately 127 metre section of the Western Australia/Northern Territory border at Surveyor Generals Corner due to inaccuracies in the 1920s for fixing positions under constraints of available technology. The parallel also defines part of the Queensland and South Australia border between the 138th and 141st meridians east. See also * 25th parallel south * 27th parallel south *Northern Territory borders *South Australian borders Today South Australia's la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Shelf
A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island is known as an ''insular shelf''. The continental margin, between the continental shelf and the abyssal plain, comprises a steep continental slope, surrounded by the flatter continental rise, in which sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope. Extending as far as 500 km (310 mi) from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rise's gradient is intermediate between the gradients of the slope and the shelf. Under the United Nations Convention on the Law of the Sea, the name continental shelf was given a legal definition as the stretch of the seabed adjacent to the shores of a par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg Case (Chondrichthyes)
An egg case or egg capsule, often colloquially called a mermaid's purse, is the casing that surrounds the eggs of oviparous sharks, skates and chimaeras. Egg cases typically contain one embryo, except for big skate and mottled skate egg cases, which contain up to 7 embryos. Oviparity is completely absent in the superorder Squalomorphii. Description Egg cases are made of collagen protein strands, and are often described as feeling rough and leathery. Some egg cases have a fibrous material covering the outside of the egg case, thought to aid in attachment to substrate. Egg cases without a fibrous outer layer can be striated, bumpy, or smooth and glossy. With the exception of bullhead shark eggs, egg cases are typically rectangular in shape with projections, called horns, at each corner. Depending on the species, egg cases may have one or more tendrils. Development Shortly after internal fertilization, the fertilized ovum enters the partially formed egg case located in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
