"Heterodontus" redirects here. For the snake, see Heterodon.
The bullhead sharks are a small order (Heterodontiformes/ˌhɛtəroʊˈdɒntɪfɔːrmiːz/) 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 1.65 metres (5.5 ft) 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.
The bullhead sharks are characterised by a broad head, heavy brow, stubby snout and small mouth. The mouth is located entirely anterior to the eye sockets, due to their protruding jaw structure. They posses a distinct groove from their nostrils to their mouths. They grow to about a meter in size, with the largest species being that of the Port Jackson shark. The eyes lack a nictitating membrane. A spiracle is present, but small. The dorsal ends of the fourth and fifth branchial arches are attached, but not fused into a "pickaxe" as in lamniform sharks. Heterodontiforms have two dorsal fins, with fin spines, as well as an anal fin. The dorsal and anal fins also contain basal cartilages, not just fin rays.[3]
SpeciesEdit
Ten living species of bullhead shark have been described:
^Slater, Tiffany S.; Ashbrook, Kate; Kriwet, Jürgen (2020). Cavin, Lionel (ed.). "Evolutionary relationships among bullhead sharks (Chondrichthyes, Heterodontiformes)". Papers in Palaeontology. 6 (3): 425–437. doi:10.1002/spp2.1299. ISSN 2056-2799.
Further readingEdit
Compagno, Leonard (2002) Sharks of the World: Bullhead, mackerel and carpet sharks Volume 2, FAO Species Catalogue, Rome. ISBN92-5-104543-7.
October 21, 2023
bullhead, shark, heterodontus, redirects, here, snake, heterodon, bullhead, sharks, small, order, heterodontiformes, ɔːr, modern, sharks, neoselachii, nine, living, species, placed, single, genus, heterodontus, family, heterodontidae, relatively, small, with, . Heterodontus redirects here For the snake see Heterodon The bullhead sharks are a small order Heterodontiformes ˌ h ɛ t e r oʊ ˈ d ɒ n t ɪ f ɔːr m iː z 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 1 65 metres 5 5 ft in maximum length They are bottom feeders in tropical and subtropical waters Bullhead sharkTemporal range 183 0 Ma Early Toarcian to Present 1 2 PreꞒ Ꞓ O S D C P T J K Pg NHorn shark Heterodontus francisciScientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClade EugnathostomataClass ChondrichthyesSuperorder GaleomorphiiOrder HeterodontiformesL S Berg 1940Family HeterodontidaeJ E Gray 1851Genus HeterodontusBlainville 1816Type speciesSqualus portusjacksoniF A A Meyer 1793SpeciesSee textThe 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 Contents 1 Description 2 Species 3 See also 4 References 5 Further readingDescription Edit nbsp Bullhead shark egg caseThe bullhead sharks are characterised by a broad head heavy brow stubby snout and small mouth The mouth is located entirely anterior to the eye sockets due to their protruding jaw structure They posses a distinct groove from their nostrils to their mouths They grow to about a meter in size with the largest species being that of the Port Jackson shark The eyes lack a nictitating membrane A spiracle is present but small The dorsal ends of the fourth and fifth branchial arches are attached but not fused into a pickaxe as in lamniform sharks Heterodontiforms have two dorsal fins with fin spines as well as an anal fin The dorsal and anal fins also contain basal cartilages not just fin rays 3 Species EditTen living species of bullhead shark have been described Heterodontus francisci Girard 1855 horn shark Heterodontus galeatus Gunther 1870 crested bullhead shark Heterodontus japonicus Maclay amp W J Macleay 1884 Japanese bullhead shark Heterodontus marshallae White Mollen O Neill Yang amp Naylor 2023 painted hornshark Heterodontus mexicanus L R Taylor amp Castro Aguirre 1972 Mexican hornshark Heterodontus omanensis Z H Baldwin 2005 Oman bullhead shark Heterodontus portusjacksoni F A A Meyer 1793 Port Jackson shark Heterodontus quoyi Freminville 1840 Galapagos bullhead shark Heterodontus ramalheira J L B Smith 1949 whitespotted bullhead shark Heterodontus zebra J E Gray 1831 zebra bullhead shark nbsp A Port Jackson shark Heterodontus portusjacksoni nbsp Dentition and oronasal grooves of a Port Jackson shark nbsp Zebra bullhead shark Heterodontus zebraSee also Edit nbsp Sharks portalList of prehistoric cartilaginous fishReferences Edit Sepkoski Jack 2002 A compendium of fossil marine animal genera Chondrichthyes entry Bulletins of American Paleontology ocean 364 560 Archived from the original on 2012 05 10 Retrieved 2008 01 09 N p Web 10 Jun 2013 http paleodb org cgi bin bridge pl a checkTaxonInfo amp taxon no 252518 amp is real user 1 Slater Tiffany S Ashbrook Kate Kriwet Jurgen 2020 Cavin Lionel ed Evolutionary relationships among bullhead sharks Chondrichthyes Heterodontiformes Papers in Palaeontology 6 3 425 437 doi 10 1002 spp2 1299 ISSN 2056 2799 Further reading EditCompagno Leonard 2002 Sharks of the World Bullhead mackerel and carpet sharks Volume 2 FAO Species Catalogue Rome ISBN 92 5 104543 7 Retrieved from https en wikipedia org w index php title Bullhead shark amp oldid 1180724773, wikipedia, wiki, book, books, library,
