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Myliobatiformes
Myliobatiformes (), commonly known as stingrays, are one of the four orders of batoids, cartilaginous fishes related to sharks. They are members of the subclass elasmobranchs. They were formerly included in the order Rajiformes, but more recent phylogenetic studies have shown the myliobatiformes to be a monophyletic group, and its more derived members evolved their highly flattened shapes independently of the skates. Characteristics Myliobatiformes share physical characteristics of a long, thin tail with serrated spines and a pancake-like body. They share many characteristics with the batoid order Rajiformes, in which they were previously included. The key difference of the orders is the Myliobatiformes' single-lobed pelvic fin, lack of a mid-tail spine, and general lack of a dorsal fin. Myliobatiformes also possess stinging spines along the tail's base, and generally possess large pectoral fins that are completely fused (except Myliobatidae) to the head. They can camoufla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Batoidea
Batomorphi is a Division (taxonomy), division of Chondrichthyes, cartilaginous fishes, commonly known as rays, this taxon is also known as the Order (biology), superorder Batoidea, but the 5th edition of ''Fishes of the World'' classifies it as the division Batomorphi. They and their close relatives, the sharks, compose the subclass Elasmobranchii. Rays are the largest group of cartilaginous fishes, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces. Anatomy Batomorphs are flat-bodied, and, like sharks, are cartilaginous fish, meaning they have a boneless skeleton made of a tough, elastic cartilage. Most batomorphs have five ventral slot-like body openings called gill slits that lead from the gills, but the Hexatrygonidae have six. Batomorph gill slits lie under the pectoral fins on the underside, whereas a shark's are on the sides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartilaginous Fish
Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeletons primarily composed of bone tissue. Chondrichthyes are aquatic vertebrates with paired fins, paired nares, placoid scales, conus arteriosus in the heart, and a lack of opercula and swim bladders. Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates. The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates and sawfish) and Holocephali ( chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class). Extant chondrichthyans range in size from the finless sleeper ray to the over whale shark. Anatomy Skeleton The skeleton is cartilaginous. The notochord is gradually replaced by a vertebral column during development, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whiptail Stingray
The whiptail stingrays are a family, the Dasyatidae, of rays in the order Myliobatiformes. They are found worldwide in tropical to temperate marine waters, and a number of species have also penetrated into fresh water in Africa, Asia, and Australia. Members of this family have flattened pectoral fin discs that range from oval to diamond-like in shape. Their common name comes from their whip-like tails, which are much longer than the disc and lack dorsal and caudal fins. All whiptail stingrays, except the porcupine ray (''Urogymnus asperrimus''), have one or more venomous stings near the base of the tail, which is used in defense. In order to sting their victims, they jerk their tails as the stinger falls off and stays in the wound that they have created. The stinger of a whiptail stingray is pointy, sharp with jagged edges. They range in size from or more across in the case of the smalleye stingray and giant freshwater stingray. Genera The taxonomy of Dasyatidae was revised ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elasmobranchii
Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks ( division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by having five to seven pairs of gill slits opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch clades. The pelvic fins in males are modified to create claspers for the transfer of sperm. There is no swim bladder; instead, these fish maintain buoyancy with large livers rich in oil. The definition of the clade is unclear with respect to fossil chondrichthyans. Some authors consider it as equivalent to Neoselachii (the crown group clade including modern sharks, rays, and all o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myliobatis Aquila
The common eagle ray or bullray (''Myliobatis aquila'') is a species of fish in the family Myliobatidae. It inhabits the eastern Atlantic Ocean (North Sea to South Africa), the Mediterranean Sea and the south-western Indian Ocean. Description The common eagle ray reaches up to in total length and has a disc width up to .Muus, B., J. G. Nielsen, P. Dahlstrom and B. Nystrom (1999). ''Sea Fish.'' p. 76. Most specimens are, however, smaller. Females grow to be larger than males. The dorsal surface is brown or black while the ventral surface is white. It has a rhomboidal disc with a pair of large, triangular pectoral fins projecting on either side, and a single dorsal fin. The blunt snout is rounded and the tail is long and slender, with a large spine at its base but no tail fin. On average, males have 72 spine serrations and females have 66 spine serrations. The spine makes about 70% of the male's length and 65% of the female's length. The mid dorsal groove, which contains the glan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eagle Ray
The eagle rays are a group of cartilaginous fishes in the family Myliobatidae, consisting mostly of large species living in the open ocean rather than on the sea bottom. Eagle rays feed on mollusks, and crustaceans, crushing their shells with their flattened teeth. They are excellent swimmers and are able to breach the water up to several meters above the surface. Compared with other rays, they have long tails, and well-defined, rhomboidal bodies. They are ovoviviparous, giving birth to up to six young at a time. They range from in length and 7 m (23 ft) in wingspan. Classification Nelson's book ''Fishes of the World'' treats cownose rays, mantas, and devil rays as subfamilies in the Myliobatidae. However, most authors (including William Toby White) have preferred to leave the Rhinopteridae and Mobulidae outside of the Myliobatidae. White (2014) retained three genera (''Aetobatus'', ''Aetomylaeus'', and ''Myliobatis'') in the Myliobatidae, while a fourth (''Pteromylaeu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zanobatidae
The panrays are a genus, ''Zanobatus'', of rays found in coastal parts of the warm East Atlantic Ocean, ranging from Morocco to Angola. It is the only genus in the family Zanobatidae, which is included in the Myliobatiformes order, but based on genetic evidence some authorities place it in Rhinopristiformes or a sister taxon to Rhinopristiformes. The two species of panrays are generally poorly known and one of the species was only scientifically described in 2016. They are up to about long, and brownish above with a heavily mottled, blotched or barred dark pattern. They are ovoviviparous and feed on benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ... invertebrates. Species There are two recognized species in the genus: * '' Zanobatus maculatus'' * '' Zanobatus schoenle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skate (fish)
Skates are Chondrichthyes, cartilaginous fish belonging to the family (biology), family Rajidae in the superorder Batoidea of Ray (fish), rays. More than 150 species have been described, in 17 genera. Arhynchobatidae, Softnose skates and Gurgesiellidae, pygmy skates were previously treated as subfamilies of Rajidae (Arhynchobatinae and Gurgesiellinae), but are now considered as distinct families. Alternatively, the name "skate" is used to refer to the entire order of Rajiformes (families Anacanthobatidae, Arhynchobatidae, Gurgesiellidae and Rajidae). Members of Rajidae are distinguished by a stiff snout and a rostrum (anatomy), rostrum that is not reduced. Taxonomy and systematics Evolution Skates belong to the ancient lineage of cartilaginous fishes. Fossil Dermal denticle, denticles (tooth-like scales in the skin) resembling those of today's chondrichthyans date at least as far back as the Ordovician, with the oldest unambiguous fossils of cartilaginous fish dating from the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexatrygonidae
The sixgill stingray (''Hexatrygon bickelli'') is a species of stingray and the only extant member of the family Hexatrygonidae. Although several species of sixgill stingrays have been described historically, they may represent variations in a single, widespread species. This flabby, heavy-bodied fish, described only in 1980, is unique among rays in having six pairs of gill slits rather than five. Growing up to long, it has a rounded pectoral fin disc and a long, triangular, and flexible snout filled with a gelatinous substance. It is brownish above and white below, and lacks dermal denticles. Benthic in nature, the sixgill stingray is usually found in deep waters over upper continental slopes and seamounts at depths of , the deepest-living stingray species known. It has been recorded from scattered locations in the Indo-Pacific from South Africa to Hawaii. This species probably uses its snout to probe for food in the bottom sediment. Its jaws are greatly protrusible, allowing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margaret Mary Smith
Margaret Mary Smith (née MacDonald; 26 September 1916 in Indwe, Cape Province, South Africa – 8 September 1987), was an ichthyologist, accomplished fish illustrator, and an academic. Early life Margaret Mary Smith was the daughter of Chisholm MacDonald and Helen Evelyn Zondagh. Her father was a medical doctor and her mother a descendant of the Voortrekker leader Jacobus Johannes Uys. She was the youngest of three children. Margaret attended Indwe High School. She was head girl and head scholar as well as chairperson of the debating society and captain of the netball and tennis teams. From 1934 to 1936 she attended Rhodes University, where she achieved a Bachelor of Science degree majoring in physics and chemistry. She also attended the Grahamstown Training College School of Music and obtained her University Teachers' Licentiate in Music for singing in 1936. Career In 1937, after she obtained her degree, she was hired as a senior demonstrator in chemistry at Rhodes Univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phil Heemstra
Phillip Clarence Heemstra (9 December 1941 – 29 August 2019) was an American-South African ichthyologist. He was born in Melrose Park, Illinois, United States as the son of Clarence William Heemstra and his wife, Lydia (born Epcke). He attended school in Ottawa, Illinois, and completed a B.Sc. Zoology in 1963 at the University of Illinois at Urbana, Illinois, as well as his MSc degree (1968) and doctorate (1974) in marine biology at the University of Miami in Miami, Florida. He moved to live in South Africa in 1978. At the time of his death, Heemstra was a curator emeritus of the South African Institute of Aquatic Biodiversity (SAIAB, formerly the J.L.B. Smith Institute of Ichthyology). He specialized in ichthyology and marine fish taxonomy. Career Heemstra was, among other things, a biologist at the marine laboratory of the U.S. Department of Natural Resources in Florida, and from 1978 to 2001 a curator of fish at J.L.B. Smith Institute of Ichthyology in Grahamstown (now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 Megaannum#SI prefix multipliers, 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 Anoxic event#Cretaceous, early Aptian Oceanic Anoxic Event 1a (OAE1a) was 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 Plateau, Ontong Java-Manihiki Plateau, Manihiki-Hikurangi Plateau, Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Onto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
