|
Squalomorphi
Squalomorphi is a superorder of sharks, generally characterized by lacking traits such as an anal fin, nictitating membrane, or suborbital shelves in the cranium. Squalomorphs are also called squalea, or squaleans. There are about 163 living species in 11 families. Squalean sharks are divided into six orders: Echinorhiniformes, Hexanchiformes, Squaliformes, Squatiniformes, Pristiophoriformes and the extinct Protospinaciformes. Extant orders Order Hexanchiformes The order Hexanchiformes is a very small and primitive order consisting of cow sharks and frilled sharks. These sharks have only 1 dorsal fin, 6-7 gill slits, and no nictitating membrane on the eyes. Cow sharks are fairly large and stocky, while frilled sharks are smaller and have eel-like bodies. The oldest fossils from this order can be dated back to the mid-Jurassic. There are six living species in 4 genera, and 2 families. * Family Hexanchidae (Cow sharks) * Family Chlamydoselachidae (Frilled sharks) Order Sq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark
Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the Division (taxonomy), division Selachii and are the sister group to the Batoidea, Batomorphi (Batoidea, rays and skate (fish), skates). Some sources extend the term "shark" as an informal category including Extinction, extinct members of Chondrichthyes (cartilaginous fish) with a shark-like morphology, such as hybodonts. Shark-like chondrichthyans such as ''Cladoselache'' and ''Doliodus'' first appeared in the Devonian Period (419–359 million years), though some fossilized chondrichthyan-like scales are as old as the Ordovician, Late Ordovician (458–444 million years ago). The earliest confirmed modern sharks (Selachii) are known from the Early Jurassic around , with the oldest known member being ''Agaleus'', though records of true shar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squatiniformes
Squatiniformes is an order of sharks belonging to Squalomorphi. It contains only a single living genus '' Squatina'', commonly known as angelsharks. The oldest genus of the order, '' Pseudorhina'' is known from the Late Jurassic of Europe. Three other genera, '' Cretasquatina'', '' Cretascyllium'' and '' Parasquatina'' are known from Cretaceous fossils from North America and Europe, though the placement of ''Parasquatina'' in the order has been questioned. All living and extinct members of the order share a similar body morphology with a highly flattened body with enlarged pectoral and pelvic fins suggestive of a bottom-dwelling ambush predator ecology. Teeth have been assigned to the modern genus from the Late Jurassic onwards, but the actual genus assignment of many of these species is unclear. The earliest records that can be assigned with confidence to the modern genus are known from the Early Cretaceous (Aptian The Aptian is an age (geology), age in the geologic timescale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexanchiformes
The Hexanchiformes Help:IPA/English, /hɛkˈsæŋkɪfɔːrmiːz/ are a primitive Order (biology), order of sharks, numbering just five extant species in two Family (biology), families, Chlamydoselachidae and Cow shark, Hexanchidae. Chlamydoselachidae are also known as frilled sharks, these sharks are very rare fishes and typically reside in deeper waters. Hexanchidae are also known as cow sharks and are the lesser known of the two types of Hexanchiformes and also reside in deep waters. Taxonomy Due to their primitive anatomy, hexanchiforms were previously considered the most Basal (phylogenetics), basal group of sharks. However, more recent phylogenetic studies indicate that while primitive, they in fact belong to the superorder Squalomorphi, which also contains Squalidae, dogfishes, angelsharks, and sawsharks, although they are thought to be the most basal member of the group. Description Hexanchiform sharks have one spineless dorsal fin located over or behind the pelvic fin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protospinax
''Protospinax'' is an extinct genus of cartilaginous fish from the Early Jurassic to Early Cretaceous of Europe and Russia. The type species, ''P. annectans'', was found in the Solnhofen limestones of southern Bavaria. Formerly known from only two specimens, further museum specimens of ''P. annectans'' were discovered at the Museum of Comparative Zoology of Harvard University in the 1990s, having been misidentified as '' Squatina'' and '' Heterodontus''. Five more species, all known only from isolated teeth, are also assigned to ''Protospinax''. ''Protospinax'' is a difficult taxon to accommodate in taxonomies. A 2023 study found it to be a squalomorph shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...; one analysis placed it closest to angelsharks and sawsharks, but the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiny Dogfish
The spiny dogfish (''Squalus acanthias''), spurdog, mud shark, or piked dogfish is one of the best known species of the Squalidae (dogfish) family of sharks, which is part of the Squaliformes order. While these common names may apply to several species, ''Squalus acanthias'' is distinguished by two spines (one anterior to each dorsal fin) and no anal fin. It lives in shallow waters and further offshore in most parts of the world, especially in temperate waters. Those in the northern Pacific Ocean were reevaluated in 2010 and found to constitute a separate species, now called the Pacific spiny dogfish (''Squalus suckleyi''). Description and behaviour The spiny dogfish has dorsal fins, no anal fin, and white spots along its back. The caudal fin has asymmetrical lobes, forming a heterocercal tail. The species name ''acanthias'' refers to the shark's two spines. These are used defensively. If captured, the shark can arch its back to pierce its captor with spines near the dorsal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. Phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydoselachidae
Chlamydoselachidae is a family of primitive deep-sea sharks in the order Hexanchiformes. They are one of only two extant families in the order alongside the cow sharks in the family Hexanchidae, and the only members of the suborder Chlamydoselachoidei. They are now represented only by two extant species in the genus '' Chlamydoselachus'': the frilled shark (''C. anguineus'') and the Southern African frilled shark (''C. africana''). However, they are thought to have been more diverse during the Late Cretaceous, where all three extant and extinct genera are known, and one other genus (''Rolfodon'') survived up to the Pliocene. The earliest remains of the family are indeterminate teeth from the Turonian of Japan. Members of this family appear to have always been closely associated with deep-sea habitats. Some extinct taxa such as ''Rolfodon goliath'' and ''Dykeius'' could grow to very large sizes. Species The following taxa are known: * '' Chlamydoselachus'' Garman, 1884 ** ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrophoridae
The Centrophoridae are a family of squaliform sharks. The family contains just two genera and about 15 species. They are sometimes called gulper sharks, but this is also the name of a specific species in the family, '' Centrophorus granulosus''. These are generally deepwater fish. While some, such as the gulper shark ''C. granulosus'', are found worldwide and fished commercially, others are uncommon and little-known. Their usual prey is other fish; some are known to feed on squid, octopus, and shrimp. Some species live on the bottom (benthic), while others are pelagic. They are ovoviviparous, with the female retaining the egg-cases in her body until they hatch. They are small to medium sharks, ranging from in adult body length. The members of the genus ''Deania'' generally have a long flattened snout. Gulper shark (''Centrophorus granulosus'') Dumb gulper shark (''Centrophorus harrissoni'') Leafscale gulper shark (''Centrophorus squamosus'') Birdbeak dogfish (''Deani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalatiidae
The Dalatiidae are the family of kitefin sharks of the order Squaliformes (the term "kitefin shark" also refers specifically to the species '' Dalatias licha''). Members of this family are small, under long, and are found worldwide. They have cigar-shaped bodies with narrow heads and rounded snouts. Several species have specialized bioluminescent organs. Though eight genera are in this family, four of them are monotypic. Genera and species * '' Dalatias'' Rafinesque, 1810 ** '' Dalatias licha'' ( Bonnaterre, 1788) (kitefin shark) ** †''Dalatias turkmenicus'' (Glikman, 1964) ** †''Dalatias orientalis'' (Malyshkina et al., 2023) * ''Euprotomicroides'' Hulley and M. J. Penrith, 1966 ** '' Euprotomicroides zantedeschia'' Hulley and M. J. Penrith, 1966 (tail-light shark) * ''Euprotomicrus'' T. N. Gill, 1865 ** '' Euprotomicrus bispinatus'' ( Quoy & Gaimard, 1824) (pygmy shark) * '' Heteroscymnoides'' Fowler, 1934 ** ''Heteroscymnoides marleyi'' Fowler, 1934 (longnose pygmy s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pristiophoriformes
A sawshark or saw shark is a member of a shark order (Pristiophoriformes ) bearing a unique long, saw-like rostrum (snout or bill) edged with sharp teeth, which they use to slash and disable their prey. There are eight species within the Pristiophoriformes, including the longnose or common sawshark ('' Pristiophorus cirratus''), shortnose sawshark ('' Pristiophorus nudipinnis''), Japanese sawshark ('' Pristiophorus japonicas''), Bahamas sawshark ('' Pristiophorus schroederi''), sixgill sawshark ('' Pliotrema warreni''), African dwarf sawshark ('' Pristiophorus nancyae''), Lana's sawshark ('' Pristiophorus lanae'') and the tropical sawshark ('' Pristiophorus delicatus''). Sawsharks are found in many areas around the world, most commonly in waters from the Indian Ocean to the southern Pacific Ocean. They are normally found at depths around 40–100 m, but can be found much lower in tropical regions. The Bahamas sawshark was discovered in deeper waters (640 m to 915 m) of the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Etmopteridae
The Etmopteridae are a family of sharks in the order Squaliformes, commonly known as lantern sharks. Their name comes from the presence of light-producing photophores on their bodies. The members of this family are small, under long, and are found in deep waters worldwide. The 45 species are placed in five genera. Three-quarters of the species are in the genus ''Etmopterus''. Genera * ''Aculeola'' * ''Centroscyllium'' * ''Etmopterus ''Etmopterus'' is a genus of Etmopteridae, lantern sharks in the Squaliformes, squaliform family (biology), family Etmopteridae. They are found in deep sea ecosystems of the Atlantic Ocean, Atlantic, Indian Ocean, Indian and Pacific Oceans. Ecol ...'' * †'' Paraetmopterus'' * '' Trigonognathus'' References Shark families Taxa named by Henry Weed Fowler {{shark-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
