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Raja (genus)
Encyclopedia
Raja is a genus
of skate
s in the family
Rajidae, containing nearly thirty species. They are flat-bodied cartilaginous fish with a rhombic shape due to their large pectoral fins extending from or nearly from the snout to the base of their tail. Their sharp snouts produced by a cranial projection of rostral cartilage. The mouth and gills located on underside of the body. They may be either solid colored or patterned, and most skates have spiny or thorn-like structures on the upper surface, and some species contain weak electrical organs within their tails. Mating typically occurs in the spring and the female lays numerous eggs
per clutch which are encapsulated in leathery cases, commonly known as “mermaid’s purses”. Species vary in size. The Hedgehog Skate (R. erinacea) adult length is 50 cm or less. The Big Skate (R. binoculata)
may be 2.5 m long. These bottom-dwellers are active during both day and night and typically feed on mollusks, crustaceans and fish. Skates are found in most parts of the world, from tropical to near arctic waters, from shallows to depths of more than 2,700 meters. Skates and related species have fossil records dating from the Upper Cretaceous period, thus this well adapted species is quite ancient.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of skate
Skate
Skates are cartilaginous fish belonging to the family Rajidae in the superorder Batoidea of rays. There are more than 200 described species in 27 genera. There are two subfamilies, Rajinae and Arhynchobatinae ....
s in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Rajidae, containing nearly thirty species. They are flat-bodied cartilaginous fish with a rhombic shape due to their large pectoral fins extending from or nearly from the snout to the base of their tail. Their sharp snouts produced by a cranial projection of rostral cartilage. The mouth and gills located on underside of the body. They may be either solid colored or patterned, and most skates have spiny or thorn-like structures on the upper surface, and some species contain weak electrical organs within their tails. Mating typically occurs in the spring and the female lays numerous eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
per clutch which are encapsulated in leathery cases, commonly known as “mermaid’s purses”. Species vary in size. The Hedgehog Skate (R. erinacea) adult length is 50 cm or less. The Big Skate (R. binoculata)
Big skate
The big skate is the largest species of skate, family Rajidae, in the waters off North America. They are found along the Pacific coast from Alaska to Baja California, typically from the intertidal zone to a depth of , and feed on benthic invertebrates and small fishes. They are unusual among...
may be 2.5 m long. These bottom-dwellers are active during both day and night and typically feed on mollusks, crustaceans and fish. Skates are found in most parts of the world, from tropical to near arctic waters, from shallows to depths of more than 2,700 meters. Skates and related species have fossil records dating from the Upper Cretaceous period, thus this well adapted species is quite ancient.
Species
- Raja ackleyi Garman, 1881 (Ocellate skate)
- Raja africana Capapé, 1977 (African skate)
- Raja asterias Delaroche, 1809 (Mediterranean starry ray)
- Raja bahamensis BigelowHenry Bryant BigelowHenry Bryant Bigelow was an American oceanographer and marine biologist.After graduating from Harvard in 1901, he began working with famed ichthyologist Alexander Agassiz. Bigelow accompanied Agassiz on several major marine science expeditions including one aboard the Albatross in 1907...
& SchroederWilliam Charles SchroederWilliam Charles Schroeder was an American ichthyologist. He was born on Staten Island, New York. He, along with his lifelong colleague Henry Bryant Bigelow, made substantial contributions to the knowledge of the fish fauna of the western North Atlantic...
, 1965 (Bahama skate) - Raja binoculata GirardCharles Frédéric GirardCharles Frédéric Girard 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...
, 1855 (Big skate) - Raja brachyura Lafont, 1873 (Blonde ray)
- Raja cervigoni BigelowHenry Bryant BigelowHenry Bryant Bigelow was an American oceanographer and marine biologist.After graduating from Harvard in 1901, he began working with famed ichthyologist Alexander Agassiz. Bigelow accompanied Agassiz on several major marine science expeditions including one aboard the Albatross in 1907...
& SchroederWilliam Charles SchroederWilliam Charles Schroeder was an American ichthyologist. He was born on Staten Island, New York. He, along with his lifelong colleague Henry Bryant Bigelow, made substantial contributions to the knowledge of the fish fauna of the western North Atlantic...
, 1964 (Finspot ray) - Raja chinensis Basilewsky, 1855
- Raja clavata Linnaeus, 1758 (Thornback ray)
- Raja cortezensis McEachran & Miyake, 1988 (Cortez' ray)
- Raja eglanteria BoscLouis Augustin Guillaume BoscLouis Augustin Guillaume Bosc was a French botanist, invertebrate zoologist, and entomologist.-Biography:...
, 1800 (Clearnose skate) - Raja equatorialis D. S. JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
& Bollman, 1890 (Equatorial ray) - Raja herwigi G. Krefft, 1965 (Cape Verde skate)
- Raja inornata D. S. JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
& C. H. GilbertCharles Henry GilbertCharles Henry Gilbert was a pioneer ichthyologist and fishery biologist of particular significance to natural history of the western United States. He collected and studied fishes from Central America north to Alaska and described many new species...
, 1881 (California ray) - Raja maderensis R. T. LoweRichard Thomas LoweRichard Thomas Lowe was a British botanist, ichthyologist, malacologist, and clergyman. In 1825 he graduated from Christ's College, Cambridge and in the same year took holy orders. He became a clergyman in the Madeira Islands in 1832, where he was a part-time naturalist, extensively studying the...
, 1838 (Madeiran ray) - Raja microocellata Montagu, 1818 (Small-eyed ray)
- Raja miraletus Linnaeus, 1758 (Brown ray)
- Raja montagui FowlerHenry Weed FowlerHenry Weed Fowler was an American zoologist born in Holmesburg, Pennsylvania.He studied at Stanford University under David Starr Jordan...
, 1910 (Spotted ray) - Raja polystigma Regan, 1923 (Speckled ray)
- Raja pulchra F. H. Liu, 1932 (Mottled skate)
- Raja radula Delaroche, 1809 (Rough ray)
- Raja rhina D. S. JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
& C. H. GilbertCharles Henry GilbertCharles Henry Gilbert was a pioneer ichthyologist and fishery biologist of particular significance to natural history of the western United States. He collected and studied fishes from Central America north to Alaska and described many new species...
, 1880 (Longnose skate) - Raja rondeleti Bougis, 1959 (Rondelet's ray)
- Raja rouxi Capapé, 1977
- Raja stellulata D. S. JordanDavid Starr JordanDavid Starr Jordan, Ph.D., LL.D. was a leading eugenicist, ichthyologist, educator and peace activist. He was president of Indiana University and Stanford University.-Early life and education:...
& C. H. GilbertCharles Henry GilbertCharles Henry Gilbert was a pioneer ichthyologist and fishery biologist of particular significance to natural history of the western United States. He collected and studied fishes from Central America north to Alaska and described many new species...
, 1880 (Starry skate) - Raja straeleni PollMax PollMax Fernand Leon Poll was a Belgian ichthyologist who specialised in Cichlidae.In the years 1946 and 1947 he organised an expedition to Lake Tanganyika....
, 1951 (Spotted skate) - Raja texana A. C. Chandler, 1921 (Roundel skate)
- Raja undulata Lacépède, 1802 (Undulate ray)
- Raja velezi Chirichigno F., 1973 (Velez ray)