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

Cockspur coral tree (Erythrina crista-galli)

Velvet coral tree or cockspur coral tree ( Erythrina crista-galli ) is a species of plant in the Fabaceae family. It is a small tree, 5-8 meters tall, with a trunk circumference of about 50 cm, irregular branches, light wood, and fissured, soft, and light brown bark. The taproot is white. The leaves are ovate, with three strands, dark green and glossy on the upper surface, and pale green on the underside. The central lobe is up to 17 cm long and up to 11 cm wide. The left and right lobes are up to 15 cm long and up to 10 cm wide. The flowers are red, arranged in racemes, at the apex, pentameric, complete, and bilaterally symmetrical. The flowers are up to 6 cm long and 4 cm wide. The pods are long, containing about 8 seeds, green when young and turning brown as they mature. The seeds are ovate, flat, and brown. It grows well in lowlands up to an elevation of 1,500 meters, with an annual rainfall of 800-1,500 mm/year, and a temperature of 20-32°C. It thrives in well-drained soils, but...

Javan broadhead planarian (Bipalium javanum)

Cacing palu or Javan broadhead planarian ( Bipalium javanum ) is a species of animal in Geoplanidae, hermaphrodite, living on the ground, predators, often called only hammerhead or broadhead or shovel worms because of wide heads and simple copulatory organs. B. javanum has a slim stature, up to 20 cm long, up to 0.5 cm wide, head wide up to 1 cm or less, small neck, widening in the middle and the back end is rounded, all black and shiny. Javan broadhead planarians walk above ground level by raising their heads and actively looking left, right and looking up using strong neck muscles. Move swiftly, track meander, climb to get through all obstacles or make a new path if the obstacle is too high. Cacing palu track and prey on earthworms and mollusks. They use muscles and sticky secretions to attach themselves to prey to lock in. The head and ends of the body are wrapped around and continue to close the body to stop prey reactions. They produce tetrodotoxins which are very strong...

Serrated pimpernel (Lindernia glandulifera)

Serrated pimpernel ( Lindernia glandulifera ) is a species of plant in the Linderniaceae family, erect, 8-9 cm long.and white roots. The stems are cylindrical or angular or curved inward. The stems green or dark red or reddish brown. The leaves are opposite, green or dark red or brown, oval or oblong, up to 3 cm long, up to 1 cm wide and serrated margins. The flowers are white and blue, 0.6-0.7 cm wide. This plant grows in colonies in karst areas, clay soils, and areas that are sometimes flooded. TAXON Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Magnoliopsida Order: Lamiales Family: Linderniaceae Genus: Lindernia All. in Auct. Syn. Meth. Stirp. Hort. Regii Taur. 3: 178 (1766) Species: Lindernia glandulifera (Blume) Backer in Onkruidfl. Jav. Suikerrietgr.: 616 (1930) VERNACULAR NAME English: Serrated pimpernel Indonesia: Tapak gergaji Java: Tapak graji Aryo Bandoro Dlium TheDlium Web: https://www.dlium.com YouTube: https://www.youtube.com/@Dlium