Hemipristis
Encyclopedia
Hemipristis is a genus
of weasel shark, family
Hemigaleidae
. It contains one extant species
, the snaggletooth shark
(H. pristis), as well as several extinct species.
Hemipristis has two distinct type of teeth in each section of its jaw. The ones on the upper jaw act like knives, cutting through the flesh of the prey, while the pointed ones on the bottom act like forks, spearing the prey and holding it down. Because this shark was poorly studied in the past and its top and bottom jaw teeth differ to such a great degree, its top and lower jaw teeth were assigned to a separate genus in the past.
While today's snaggletooth shark is not very large or dangerous, there was another species, Hemipristis serra, which lived in the Atlantic Ocean during the Oligocene
and Miocene
. This shark was considerably larger than its modern day relative, and had much larger teeth. Marks made by the teeth of H. serra are often found on the bones of the manatee
Metaxytherium
leading some scientists to think that H. serra specialized in these sirenians.
The unusual teeth of Hemipristis serra are highly prized by collectors because they are often found in sediments in Southern Florida
that yield extremely colorful fossil shark teeth. Their outstandingly large serrations make it a favorite collectible.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of weasel shark, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Hemigaleidae
Hemigaleidae
The weasel sharks are a family, Hemigaleidae, of ground sharks found from the eastern Atlantic Ocean to the continental Indo-Pacific. They are found in shallow coastal waters to a depth of 100 m ....
. It contains one extant species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, the snaggletooth shark
Snaggletooth shark
The snaggletooth shark, Hemipristis elongatus, is a species of weasel shark, family Hemigaleidae, and the only extant member of the genus Hemipristis. It is found in the Indo-West Pacific, including the Red Sea, from southeast Africa to the Philippines, north to China, and south to Australia, at...
(H. pristis), as well as several extinct species.
Hemipristis has two distinct type of teeth in each section of its jaw. The ones on the upper jaw act like knives, cutting through the flesh of the prey, while the pointed ones on the bottom act like forks, spearing the prey and holding it down. Because this shark was poorly studied in the past and its top and bottom jaw teeth differ to such a great degree, its top and lower jaw teeth were assigned to a separate genus in the past.
Hemipristis serra
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
and Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
. This shark was considerably larger than its modern day relative, and had much larger teeth. Marks made by the teeth of H. serra are often found on the bones of the manatee
Manatee
Manatees are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows...
Metaxytherium
Metaxytherium
Metaxytherium is an extinct genus of dugong that lived from the Miocene to the Pleistocene. Its remains have been found in Africa, Asia, Europe, North America, and South America.- Sources :*Manatees and Dugongs of the World by Jeff Ripple...
leading some scientists to think that H. serra specialized in these sirenians.
The unusual teeth of Hemipristis serra are highly prized by collectors because they are often found in sediments in Southern Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
that yield extremely colorful fossil shark teeth. Their outstandingly large serrations make it a favorite collectible.
Species
- Hemipristis elongatus
- Hemipristis curvatus
- Hemipristis serra - An extinct species from the Oligocene-Miocene of Florida, South Carolina, and other areas on the Atlantic coast.