The weasel sharks are a family, the Hemigaleidae, of ground sharks found from the eastern

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

to the continental Indo-Pacific. They are found in shallow coastal waters to a depth of . Most species are small, reaching no more than long, though the

snaggletooth shark The snaggletooth shark, or fossil shark (''Hemipristis elongata''), is a species of weasel shark in the family Hemigaleidae, and the only extant member of the genus ''Hemipristis''. It is found in the Indo-West Pacific, including the Red Sea, from ...

(''Hemipristis elongatus'') may reach . They have horizontally oval eyes, small spiracles, and precaudal pits. Two

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...

s occur with the base of the first placed well forward of the pelvic fins. The

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

has a strong ventral lobe and undulations on the dorsal lobe margin. They feed on a variety of small bony fishes and

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s; at least two species specialize on cephalopods. They are not known to have attacked people.

Genera and species

The eight known species in this family are placed in four genera. ''Hemipristis'' is placed in the subfamily Hemipristinae, while ''Chaenogaleus'', ''Hemigaleus'', and ''Paragaleus'' are placed in the subfamily Hemigaleinae.Haaramo, M. (2005)
Hemigaleidae - weasel sharks
''Mike's Phylogeny Archive''. Retrieved on March 3, 2009.

''Chaenogaleus''

This genus consists of a single species, the hooktooth shark, characterized by long, hooked teeth in the lower jaw and no toothless spaces at the midlines of the jaws. The

gill slit Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In con ...

s are very long, the snout is wedge-shaped, and the fins are not falcate.Compagno, Leonard J. V. (1984) ''Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date''.

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Food and Agriculture Organization The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

. . Known fossil species include '' C. affinis''. * ''

Chaenogaleus macrostoma The hooktooth shark (''Chaenogaleus macrostoma''), is a weasel shark of the family Hemigaleidae, the only extant member of the genus '' Chaenogaleus'', but there is an extinct species, '' Chaenogaleus affinis''. The hooktooth shark is found in ...

'' ( Bleeker, 1852) (hooktooth shark

''Hemigaleus''

This genus is characterized by a rounded snout and short gill slits. The mouth is short and broadly arched; the teeth have very short cusps, without toothless spaces at the jaw midlines. The dorsal and pelvic fins, and the lower caudal lobe are strongly falchate. At one time or another, this genus has encompassed up to nine species, but most were eventually split off into other genera. ''Neogaleus'' Whitley, 1931 is a junior synonym of this genus. * '' Hemigaleus australiensis'' W. T. White,

Last A last is a mechanical form shaped like a human foot. It is used by shoemakers and cordwainers in the manufacture and repair of shoes. Lasts typically come in pairs and have been made from various materials, including hardwoods, cast iron, an ...

& Compagno, 2005 (Australian weasel shark

* '' Hemigaleus microstoma'' Bleeker, 1852 (sicklefin weasel shark

''Hemipristis''

This genus contains a single extant species, the

. It is distinguished by a rounded snout and very long gill slits. The mouth is long with toothless spaces at the midlines; the lower teeth have very long, strongly hooked cusps and protrude when the mouth is closed. The fins are strongly falchate. ''Dirrhizodon'' Kunzinger, 1871 and ''Heterogaleus'' Gohar & Mazhar, 1964 are junior synonyms of this genus. Several fossil species are known, including '' H. curvatus'' and '' H. serra''; in the

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

, this genus had a global distribution. * ''

Hemipristis elongata The snaggletooth shark, or fossil shark (''Hemipristis elongata''), is a species of weasel shark in the family Hemigaleidae, and the only extant member of the genus ''Hemipristis''. It is found in the Indo-West Pacific, including the Red Sea, fro ...

'' ( Klunzinger, 1871) (snaggletooth shark

''Paragaleus''

This genus has a rounded or slightly pointed snout, short gill slits, and a broadly arched mouth. The upper teeth have long cusps, and no toothless spaces occur at the jaw midlines. The dorsal and pelvic fins and the lower caudal lobe are not falchate in shape. Known fossil species include '' P. pulchellus'' and '' P. antunesi''. * '' Paragaleus leucolomatus'' Compagno &

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, 1985 (whitetip weasel shark

* '' Paragaleus pectoralis'' (

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, 1906) (Atlantic weasel shark

* '' Paragaleus randalli'' Compagno, Krupp & K. E. Carpenter, 1996 (slender weasel shark

* '' Paragaleus tengi'' ( J. S. T. F. Chen, 1963) (straight-tooth weasel shark

References

{{Taxonbar, from=Q574604 Shark families Taxa named by Leonard Compagno