A team of marine biologists led by a Florida International University researcher has described a new species of the shark genus Sphyrna from the Caribbean and the Southwest Atlantic.
Named for the unusual and distinctive form of their heads, hammerhead sharks belong to the family Sphyrnidae.
They are found worldwide, preferring life in warmer waters along coastlines and continental shelves.
“Hammerhead sharks are a monophyletic lineage of carcharhiniform sharks first appearing in the Miocene epoch,” said Florida International University researcher Cindy Gonzalez and her colleagues from the United States and Canada.
“They are characterized by their laterally expanded, dorsoventrally compressed head or ‘cephalofoil’ and currently comprise nine named species.”
“Hammerhead sharks are one of the most threatened shark families mainly due to overexploitation, with all species but one (Sphyrna gilberti) being globally listed as Vulnerable, Endangered, or Critically Endangered by the IUCN,” they added.
“There are four species of small-bodied hammerheads (less than 1.5 m total length at first maturity) that are endemic to the Americas: Sphyrna tiburo, Sphyrna tudes, Sphyrna corona, and Sphyrna media.”
“Sphyrna corona occurs only in the Eastern Pacific, Sphyrna tudes occurs only in the Western Atlantic, and two species occur in both oceanic basins, including the scoophead shark (Sphyrna media) and the bonnethead shark (Sphyrna tiburo).”
The newly-described Sphyrna species is a small hammerhead shark less than 1.5 m in length.
Scientifically named Sphyrna alleni (common name is the shovelbill shark), it has a flat, shovel shaped head that lacks indentations on its anterior edge.
“Sphyrna alleni is distinct from Sphyrna tiburo because in this species the anterior margin of the head is more rounded and the lobules on the posterior margin are not present,” the researchers said.
“Precaudal vertebral counts for Sphyrna alleni are between 80 and…
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