The weasel sharks are a family, the Hemigaleidae, of

ground sharks Carcharhiniformes ( from Classical Greek ' (karcharos) 'sharp/jagged' and ' (rhinos) 'nose', plus Latin ''forme'' 'shape'), commonly known as ground sharks, are the largest order of sharks, with over 270 species. They include a number of common ...

found from the eastern

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

to the continental

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

. They are found in shallow coastal waters to a depth of . Most species are small, reaching no more than long, though the snaggletooth shark (''Hemipristis elongatus'') may reach . They have horizontally oval eyes, small spiracles, and precaudal pits. Two

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

s occur with the base of the first placed well forward of the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s. The

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

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

bony fish Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ...

es and

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s; at least two species specialize on

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

s. 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 c ...

s are very long, the

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, Rostrum (anatomy), rostrum, beak or proboscis. The wet furless surface around the nostrils of the n ...

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''.

Rome Rome (Italian language, Italian and , ) is the capital city and most populated (municipality) of Italy. It is also the administrative centre of the Lazio Regions of Italy, region and of the Metropolitan City of Rome. A special named with 2, ...

Food and Agriculture Organization The Food and Agriculture Organization of the United Nations; . (FAO) is a specialized agency of the United Nations that leads international efforts to defeat hunger and improve nutrition and food security. Its Latin motto, , translates ...

. . Known fossil species include '' C. affinis''. * '' Chaenogaleus macrostoma'' ( 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 In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

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 come in many styles and sizes, depending on the exact job they are designed for. Common variations ...

& Compagno, 2005 (Australian weasel shark

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

''Hemipristis''

This genus contains a single extant species, the snaggletooth shark. 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 '' Hemipristis curvatus, H. curvatus'' and '' H. serra''; in the

Tertiary Tertiary (from Latin, meaning 'third' or 'of the third degree/order..') may refer to: * Tertiary period, an obsolete geologic period spanning from 66 to 2.6 million years ago * Tertiary (chemistry), a term describing bonding patterns in organic ch ...

, this genus had a global distribution. * '' Hemipristis elongata'' ( 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 '' Paragaleus pulchellus, P. pulchellus'' and '' P. antunesi''. * '' Paragaleus leucolomatus'' Compagno & Smale, 1985 (whitetip weasel shark

* '' Atlantic weasel shark, Paragaleus pectoralis'' (

Garman Garman is a surname or first name. Notable people with the name include: Sports * Ann Garman, All-American Girls Professional Baseball League player * Judi Garman (born 1954), American softball coach * Mike Garman (born 1949), American baseball pla ...

, 1906) (Atlantic weasel shark

* '' Slender weasel shark, Paragaleus randalli'' Compagno,

Krupp Friedrich Krupp AG Hoesch-Krupp (formerly Fried. Krupp AG and Friedrich Krupp GmbH), trade name, trading as Krupp, was the largest company in Europe at the beginning of the 20th century as well as Germany's premier weapons manufacturer dur ...

& K. E. Carpenter, 1996 (slender weasel shark

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

References

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