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Whitespotted Bullhead Shark
The whitespotted bullhead shark, ''Heterodontus ramalheira'', is a bullhead shark of the family Heterodontidae found in the western and northern Indian Ocean between latitudes 22°N to 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 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 islan ... 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 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 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 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. From 1922 to 1937, he was married to He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bullhead Shark
The bullhead sharks are members of the genus ''Heterodontus'', the only members of the family Heterodontidae and only living members of the order Heterodontiformes. 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. The oldest fossils of the modern genus date to the Late Jurassic. Despite the very ancient origins of this genus and its abundance in the fossil record, phylogenetic evidence indicates that all extant species in the genus arose from a single common ancestor that survived the Cretaceous-Paleogene extinction, with diversification into modern species only starting around the mid-Eocene. Description Bullhead sharks have tapered bodies, with most species reaching around in length. Their bodies vary in colour, including shades of grey, brown, and red and pale colours, and are covered in a variety of pattern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) 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". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...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 approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica, depending on the definition in use. The Indian Ocean has large marginal or regional seas, including the Andaman Sea, the Arabian Sea, the Bay of Bengal, and the Laccadive Sea. Geologically, the Indian Ocean is the youngest of the oceans, and it has distinct features such as narrow continental shelf, continental shelves. Its average depth is 3,741 m. It is the warmest ocean, with a significant impact on global climate due to its interaction with the atmosphere. Its waters are affected by the Indian Ocean Walker circulation, resulting in unique oceanic currents and upwelling patterns. The Indian Ocean is ecologically diverse, with important ecosystems such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
22nd Parallel North
Following are circles of latitude between the 20th parallel north and the 25th parallel north: 21st parallel north The 21st parallel north is a circle of latitude that is 21 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. At this latitude the sun is visible for 13 hours, 25 minutes during the summer solstice and 10 hours, 51 minutes during the winter solstice. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 21° north passes through: : 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. In 1899, the 22nd parallel was used by British colonial authorities to define the Egypt–Sudan border. Although Egypt continues to claim the 22nd pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
26th Parallel South
Following are circles of latitude between the 25th parallel south and the 30th parallel south: 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. 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. Around the world Starting at the Prime Meridian and heading eastwards, the parallel 26° south passes through: : 27th parallel sout ... [...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 ... [...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 chondrichthyans. Living chondricthyans that produce egg cases include some 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 Squalomorphi. Egg cases are also thought to have been produced by some extinct chondrichthyan groups, such as hybodonts and xenacanths. 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 eac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
