Skip to main content

Shovelbill shark (Sphyrna alleni), hammerhead shark (Sphyrnidae) from Caribbean and Southwest Atlantic

Shovelbill shark (Sphyrna alleni), hammerhead shark (Sphyrnidae) from Caribbean and Southwest Atlantic

NEWS - Researchers have identified a new species of hammerhead shark as the shovelbill shark or Requin-marteau pelle or Tiburón Cabeza de Pala (Sphyrna alleni) collected at Robinson Point and Riversdale Village, Belize, and provided by local fishermen in 2016 and 2019. S. alleni is named after Paul G. Allen (1953-2018), a philanthropist who supported shark research and conservation.

Shovelbill shark is max 150 cm long when mature with a flat, shovel-shaped head that lacks a notch on the anterior margin, a pointed (triangular) cephalofoil in both sexes and a distinct protrusion in males. The posterior margin is lobulated.

The posterior teeth are enlarged, molar-like, the first dorsal tip is anterior to the pelvic origin and the posterior margin of the anus is shallowly concave. It differs from S. tiburo in that the anterior margin of the head is more rounded and the posterior margin lacks lobules. The number of precaudal vertebrae for S. alleni is between 80-83 (~10 more vertebrae than S. tiburo).

The distribution range is in coastal waters, estuaries, coral reefs, seagrass beds and sandy bottoms from Belize to Brazil. Its presence has been confirmed in the Caribbean in Belize, Panama, Colombia, Trinidad and Tobago and in the southwest Atlantic in Brazil.

S. alleni and S. tiburo are separated into two gene pools when examining 12 nuclear microsatellites with many private alleles observed. Visual inspection reveals a more pointed anterior margin of the cephalofoil in S. alleni which is consistent with geometric morphometric analysis and precaudal vertebrae count.

These species diverged between 3.61-5.62 million years ago which would be before the uplift of the Isthmus of Panama. It is possible that S. alleni and S. vespertina are sister lineages and S. tiburo diverged from them as it expanded into the subtropical and temperate regions of the Atlantic.

Phylogenetic reconstruction and head morphology also suggest S. tiburo is a species complex consisting of south central (Caribbean), northwestern (Gulf of Mexico, Florida, South and North Carolina) and eastern Pacific lineages.

Bonnetheads are currently rated as Globally ‘Endangered’ by the IUCN, but they have been assessed as an American amphibian species. The species is well managed in the higher latitudes of its Northern Hemisphere Atlantic range, but is heavily fished and poorly managed elsewhere.

Original research

Cindy Gonzalez, Bautisse Postaire, William Driggers, Susana Caballero & Demian Chapman (2024), Sphyrna alleni sp. nov., a new hammerhead shark (Carcharhiniformes, Sphyrnidae) from the Caribbean and the Southwest Atlantic. Zootaxa 5512 (4): 491–511, DOI: 10.11646/zootaxa.5512.4.2

Dlium theDlium

Popular Posts

Humpback whales (Megaptera novaeangliae) manufacture bubble-nets as tools to increase prey intake

NEWS - Humpback whales ( Megaptera novaeangliae ) create bubble net tools while foraging, consisting of internal tangential rings, and actively control the number of rings, their size, depth and horizontal spacing between the surrounding bubbles. These structural elements of the net increase prey intake sevenfold. Researchers have known that humpback whales create “bubble nets” for hunting, but the new report shows that the animals also manipulate them in a variety of ways to maximize catches. The behavior places humpbacks among the rare animals that make and use their own tools. “Many animals use tools to help them find food, but very few actually make or modify these tools themselves,” said Lars Bejder, director of the Marine Mammal Research Program (MMRP), University of Hawaii at Manoa. “Humpback whales in southeast Alaska create elaborate bubble nets to catch krill. They skillfully blow bubbles in patterns that form a web with internal rings. They actively control details such ...

Javan mocca or Javan slender caesar (Amanita javanica)

OPINION - Javan mocca or Javan slender caesar ( Amanita javanica ) is a mysterious fungus species and has been enigmatic since it was first reported by Boedijn in 1951 and after that no explanation or reporting of specimens is believed to be the same as expected. Boedijn (1951) described A. javanica which grew on Java island as having the characteristics covered in the Amanita genus. Corner and Bas in 1962 tried to describe Javan mocca and all species in Amanita based on specimens in Singapore. Over time some reports say that they have found A. javanica specimens in other Southeast Asia including also China, Japan, India and Nepal. But there is no definitive knowledge and many doubt whether the specimen is the same as described by Boedijn (1951). I was fortunate to have seen this species one afternoon and soon I took out a camera for some shots. In fact, I've only met this mushroom species once. Javan mocca is an endangered species and I have never seen in my experience in...

Javanese grasshopper (Valanga nigricornis)

Wooden grasshopper or Javanese grasshopper ( Valanga nigricornis ) is an animal species of Acrididae, grasshoppers that have at least 18 subspecies, insects with very wide diversity in color and size, sexual dimorphism in which females are larger in size and paler in color. V. nigricornis in males has a length of 45-55 millimeters and females 15-75 mm. The head is square and green or yellow or brown or black in color. A pair of antennas has a black color. The eyes are large and gray or white or brownish. The hind legs are very large and have a green or yellow or brown or black color, plain or brindle. The limbs have two rows of large and long spines with black tips facing backward. The wings have a length exceeding the belly, a rough surface and are brown or green or yellow or black in color with pulse lines forming spaces filled with black color. The hind wings are rose red which will be visible when flying. Nymphs are pale green or yellow or brown or blackish in color. Javanese gr...