A group of marine biologists led by a Florida Global College researcher has described a original species of the shark genus Sphyrna from the Caribbean and the Southwest Atlantic.
Sphyrna alleni, a male smooth in Riversdale, Belize. Image credit ranking: Cindy Gonzalez.
Named for the extraordinary and distinctive produce of their heads, hammerhead sharks belong to the household Sphyrnidae.
They’re chanced on worldwide, preferring lifestyles in hotter waters alongside coastlines and continental cabinets.
“Hammerhead sharks are a monophyletic lineage of carcharhiniform sharks first showing within the Miocene epoch,” mentioned Florida Global College researcher Cindy Gonzalez and her colleagues from the United States and Canada.
“They’re characterized by their laterally expanded, dorsoventrally compressed head or ‘cephalofoil’ and currently comprise nine named species.”
“Hammerhead sharks are one among basically the most threatened shark families mainly because of overexploitation, with all species but one (Sphyrna gilberti) being globally listed as Susceptible, Endangered, or Seriously Endangered by the IUCN,” they added.
“There are four species of diminutive-bodied hammerheads (lower than 1.5 m entire length first and predominant maturity) which would possibly per chance be endemic to the Americas: Sphyrna tiburo, Sphyrna tudes, Sphyrna corona, and Sphyrna media.”
“Sphyrna corona occurs most efficient within the Jap Pacific, Sphyrna tudes occurs most efficient within the Western Atlantic, and two species happen in both oceanic basins, at the side of the scoophead shark (Sphyrna media) and the bonnethead shark (Sphyrna tiburo).”
The newly-described Sphyrna species is a diminutive hammerhead shark lower than 1.5 m in length.
Scientifically named Sphyrna alleni (recurring title is the shovelbill shark), it has a flat, shovel formed head that lacks indentations on its anterior edge.
“Sphyrna alleni is decided from Sphyrna tiburo because on this species the anterior margin of the head is more rounded and the lobules on the posterior margin are no longer most up-to-date,” the researchers mentioned.
“Precaudal vertebral counts for Sphyrna alleni are between 80 and 83 — spherical 10 more vertebrae than in Sphyrna tiburo.”
“Given some similarity in cephalofoil form in Sphyrna alleni and Sphyrna vespertina it is that you can imagine that they are sister lineages and Sphyrna tiburo diverged from them as it expanded into the subtropical and temperate Atlantic, with a later separation of Sphyrna vespertina and the incipient Sphyrna alleni by the Isthmus closure.”
Sphyrna alleni is dispensed in coastal waters, estuaries, coral reefs, seagrass beds, and sand bottoms from Belize to Brazil.
The presence of the species has been confirmed within the Caribbean in Belize, Panama, Colombia, Trinidad and Tobago, and within the southwestern Atlantic in Brazil.
“Bonnetheads are currently assessed as Globally Endangered by the IUCN but they’ve been assessed as one amphi-American species,” the scientists mentioned.
“The assessment highlights that the species is wisely managed in bigger latitude aspects of its northern hemisphere Atlantic differ (U.S., Bahamas) but heavily fished and poorly managed in other places, with evidence of population collapse in Brazil and within the course of mighty of the Tropical Jap Pacific.”
“Reevaluating this assessment thinking about the geographic distribution of Sphyrna tiburo and Sphyrna alleni is now warranted,” they mentioned.
“Given how fishing and administration is dispensed it is seemingly that the IUCN residence of Sphyrna tiburo would enhance and Sphyrna alleni would warrant a highly threatened residence.”
“Bigger administration consideration is important to rebuild populations of Sphyrna alleni, which could perhaps additionally arrangement shut the produce of restrictions on gillnets and trawls as these instruments kinds are accountable for most catches of this coastal species.”
The invention of Sphyrna alleni is reported in a paper within the journal Zootaxa.
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Cindy Gonzalez et al. 2024. Sphyrna alleni sp. nov., a original hammerhead shark (Carcharhiniformes, Sphyrnidae) from the Caribbean and the Southwest Atlantic. Zootaxa 5512 (4): 491-511; doi: 10.11646/zootaxa.5512.4.2
