dcsimg
Image of Mexican Hornshark
Creatures » » Animal » » Vertebrates » » Cartilaginous Fishes » » Modern Sharks » » Bullhead Sharks »

Mexican Hornshark

Heterodontus mexicanus Taylor & Castro-Aguirre 1972

Diagnostic Description

provided by FAO species catalogs
fieldmarks: Dorsal fins with spines, anal fin present, colour pattern of large dark spots of one-half eye diameter or more on light background, a light bar present on space between supraorbital ridges, first dorsal-fin origin over pectoral-fin bases. Supraorbital ridges low, gradually ending posteriorly; interorbital space shallowly concave, depth between ridges less than one-fourth eye length. Anterior holding teeth with a cusp and a pair of cusplets in adults, posterior molariform teeth strongly carinate and not greatly expanded and rounded. Pre-first dorsal-fin length 24 to 29% and anal-caudal space 6 to 9%of total length. Lateral trunk denticles large and rough, area behind first dorsal fin with about 70 to 130 denticles per cm² in adults. Propterygium fused to mesopterygium. First dorsal-fin spine directed obliquely posterodorsally in juveniles and adults; first dorsal-fin origin slightly anterior to pectoral-fin insertions, behind pectoral-fin midbases, and well posterior to fifth gill openings; first dorsal-fin insertion well anterior to pelvic-fin origins and well behind pectoral-fin insertions; first dorsal-fin free rear tip about opposite to or slightly ahead of pelvic-fin origins; first dorsal fin low and weakly falcate in adults, height 8 to 18% of total length, first dorsal fin about as large as pelvic fins; second dorsal-fin origin over or slightly in front of pelvic-fin rear tips, weakly falcate and nearly as large as first dorsal fin. Anal fin subangular and rounded to weakly falcate, with apex reaching lower caudal-fin origin or falling somewhat behind it when laid back; anal-caudal space between 1 and 2 times anal-fin base. Total vertebral count unknown, precaudal count 60 to 70, monospondylous precaudal count 30 to 34, diplospondylous precaudal count 30 to 38, pre-first dorsal-fin spine count 14 to 16, and count from diplospondylous transition to second dorsal-fin spine 9 to 14. Egg cases with thick, T-shaped paired spiral flanges, transverse to case axis, and a pair of long, slender tendrils on case apex; flanges with five turns. A small species, mature between 50 and 70 cm. Background colour of dorsal surface light grey-brown with large black spots on body and fins, these one-half eye diameter or more in size; body without a dark harness pattern; head with a light-coloured bar on interorbital surface of head and 1 or 2 dusky indistinct blotches under eye; fins without abrupt dark tips and white dorsal-fin apices; hatchlings without whorls on fins and body.

References

  • Franke & Acero, 1991
  • Taylor & Castro-Aguirre, 1972

license
cc-by-nc-sa-3.0
bibliographic citation
Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
author
Food and Agriculture Organization of the UN
original
visit source
partner site
FAO species catalogs

Distribution

provided by FAO species catalogs
Eastern Pacific: Mexico (southern Baja California, the Gulf of California, and southern Pacific coast) south to Guatemala, Panama (Gulf of Panama), Colombia, probably Ecuador and Peru.
license
cc-by-nc-sa-3.0
bibliographic citation
Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
author
Food and Agriculture Organization of the UN
original
visit source
partner site
FAO species catalogs

Size

provided by FAO species catalogs
Maximum size about 70 cm. Egg cases about 8 to 9 cm long, young hatch at about 14 cm; males maturing between 40 and 50 cm and reaching at least 55 cm.
license
cc-by-nc-sa-3.0
bibliographic citation
Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
author
Food and Agriculture Organization of the UN
original
visit source
partner site
FAO species catalogs

Brief Summary

provided by FAO species catalogs
A warm-temperate and tropical bullhead shark of littoral continental waters, found on rocky bottom including reefs and seamounts, on coral reefs, and on sandy areas.From close inshore down to 20 to 50 m depth. Common in the upper Gulf of California. Oviparous. The long tendrils and rigid, T-shaped spiral flanges on the egg cases of this shark suggest that wedging of the eggs in crevices through the action of flexible flanges has been replaced by anchoring of the cases to the substrate by the tendrils, unlike other bullhead sharks with flexible-flanged eggs. The heavy T-flanges may serve instead to protect the egg from impacts and egg-predators. Feeds on crabs and demersal fishes including midshipman (Porichthys, Batrachoididae).
license
cc-by-nc-sa-3.0
bibliographic citation
Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
author
Food and Agriculture Organization of the UN
original
visit source
partner site
FAO species catalogs

Benefits

provided by FAO species catalogs
Interest to fisheries minimal. Small numbers are or were taken as a bycatch of the shrimp fishery in Mexico and processed into fishmeal along with other sharks. It is also caught in gill nets set for small sharks. Observed by divers in the Gulf of California, but not a special focus for ecotouristic diving.
license
cc-by-nc-sa-3.0
bibliographic citation
Sharks of the world An annotated and illustrated catalogue of shark species known to date. Volume 2 Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Leonard J.V. Compagno 2001.  FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 2001. p.269.
author
Food and Agriculture Organization of the UN
original
visit source
partner site
FAO species catalogs

Life Cycle

provided by Fishbase
Oviparous (Ref. 50449). Distinct pairing with embrace (Ref. 205).
license
cc-by-nc
copyright
FishBase
Recorder
Susan M. Luna
original
visit source
partner site
Fishbase

Trophic Strategy

provided by Fishbase
Found on littoral continental waters, on rocky and sandy areas from close inshore down to at least 20 to 50 m depth. Also found on seamounts. Reported to reach 165 cm (Ref. 37955). Feeds on crabs and demersal fishes including midshipman (Porichthys, Batrachoididae) (Ref. 43278).
license
cc-by-nc
copyright
FishBase
Recorder
Estelita Emily Capuli
original
visit source
partner site
Fishbase

Biology

provided by Fishbase
Found on littoral continental waters, on rocky and sandy areas from close inshore down to at least 20 m depth. Reported to reach 165 cm (Ref. 37955). Feeds on crabs and demersal fishes including midshipman (Porichthtys) (Ref. 43278). Oviparous (Ref. 37955). Utilized as fishmeal.
license
cc-by-nc
copyright
FishBase
Recorder
Kent E. Carpenter
original
visit source
partner site
Fishbase

Importance

provided by Fishbase
fisheries: subsistence fisheries
license
cc-by-nc
copyright
FishBase
Recorder
Kent E. Carpenter
original
visit source
partner site
Fishbase

Mexican hornshark

provided by wikipedia EN

The Mexican hornshark (Heterodontus mexicanus) is a bullhead shark of the family Heterodontidae. This shark is grey-brown in color, with black spots scattered on the fins and body. It has a cylindrical trunk, conical head, and small spiracles behind the eyes. The snout of the Mexican hornshark is very round and blunt. Like all members of the order Heterodontiformes, this shark has fin spines in front of both of its dorsal fins. The first dorsal fin originates before the pectoral fins, while the second dorsal fin originates behind the pelvic fins. The Mexican hornshark reaches a maximum length around 70 cm, but usually reaches between 50 and 60 cm on average. Young hornsharks hatch around 14 cm.[2]

Habitat and range

Jaws

Mexican hornsharks are distributed throughout the coast of the Eastern Pacific, mainly around southern Baja California, and possibly as far south as Peru. The rocky bottoms, coral reefs, and sandy areas of the littoral zone create the habitat of this hornshark. The Mexican hornshark can be found at a maximum depth of 50 m, but is usually found down to 20 m.[3]

Behavior

Like all members of the order Heterodontiformes, the Mexican hornshark is oviparous. After an unknown gestation period, the female attaches an unknown number of spiral-shaped egg cases to rocks on the sea floor. The length of the incubation period of these egg cases is also unknown. Not much about the feeding habits of the Mexican hornshark is known, but it most likely feeds on shelled invertebrates. Because of its size, this shark poses no danger to humans.

Conservation

The Mexican hornshark is listed as least concern by the IUCN Red List. This shark is not considered to have commercial value, but it is at risk nonetheless because it is taken as bycatch by fishing operations that use bottom gillnets. Mexican hornsharks caught as bycatch are either discarded or used in fishmeal. If released back into the water, these sharks are hardy enough to survive, but unfortunately many discarded hornsharks are left on beaches to die. Overall, the threat to Mexican hornsharks is considerable, as their range is restricted and they are frequently caught.[1]

References

  1. ^ a b Pollom, R., Avalos, C., Bizzarro, J., Burgos-Vázquez, M.I., Cevallos, A., González, A., Herman, K., Mejía-Falla, P.A., Morales-Saldaña, J.M., Navia, A.F., Pérez Jiménez, J.C. & Sosa-Nishizaki, O. 2020. Heterodontus mexicanus. The IUCN Red List of Threatened Species 2020: e.T60235A124454650. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T60235A124454650.en . Retrieved 11 May 2022 .
  2. ^ Godknecht, Alexander J. "Mexican hornshark (Heterodontus mexicanus)". shark.ch.
  3. ^ Compagno, L.J.V. "Mexican hornshark (Heterodontus mexicanus)". Sharks of the World. species-identification.org.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Mexican hornshark: Brief Summary

provided by wikipedia EN

The Mexican hornshark (Heterodontus mexicanus) is a bullhead shark of the family Heterodontidae. This shark is grey-brown in color, with black spots scattered on the fins and body. It has a cylindrical trunk, conical head, and small spiracles behind the eyes. The snout of the Mexican hornshark is very round and blunt. Like all members of the order Heterodontiformes, this shark has fin spines in front of both of its dorsal fins. The first dorsal fin originates before the pectoral fins, while the second dorsal fin originates behind the pelvic fins. The Mexican hornshark reaches a maximum length around 70 cm, but usually reaches between 50 and 60 cm on average. Young hornsharks hatch around 14 cm.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Diet

provided by World Register of Marine Species
Feeds on crabs and demersal fishes including midshipman (Porichthys, Batrachoididae).

Reference

Compagno, L.J.V. (2001). Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Volume 2. Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 269p.

license
cc-by-4.0
copyright
WoRMS Editorial Board
contributor
Elien Dewitte [email]

Habitat

provided by World Register of Marine Species
A warm-temperate and tropical bullhead shark of littoral continental waters, found on rocky bottom including reefs and seamounts, on coral reefs, and on sandy areas from close inshore down to 20 to 50 m depth.

Reference

Compagno, L.J.V. (2001). Sharks of the world. An annotated and illustrated catalogue of shark species known to date. Volume 2. Bullhead, mackerel and carpet sharks (Heterodontiformes, Lamniformes and Orectolobiformes). FAO Species Catalogue for Fishery Purposes. No. 1, Vol. 2. Rome, FAO. 269p.

license
cc-by-4.0
copyright
WoRMS Editorial Board
contributor
Elien Dewitte [email]