Acanthias

Acanthias is a historic taxonomic name associated with a group of small, spiny sharks commonly known as spiny dogfishes. The term derives from Greek and was used in older classifications to describe thorn-like spines on the dorsal fins. In current taxonomy, the species most often linked with Acanthias is placed in the genus Squalus, with the well-known spiny dogfish named Squalus acanthias; as a result, the genus Acanthias is generally considered obsolete in modern scientific usage.

Description and range: Spiny dogfish are small, slender sharks that typically reach about 1 meter in length. They have two dorsal fins, each equipped with a characteristic spine, the first of which can injure or deter predators. They lack an anal fin and have a long, rounded caudal fin. Coloration is generally brown to gray, often with a mottled pattern. They inhabit temperate coastal waters of the Northern Hemisphere, including parts of the Atlantic and Pacific Oceans, from shallow estuaries to several hundred meters deep, and they often move in large schools.

biology and ecology: Spiny dogfish are slow-growing and late-maturing, with relatively long lifespans. They are ovoviviparous, giving birth to live young after a lengthy gestation that can last up to about two years, with litters typically consisting of a small number of pups. Their diet includes small fish and invertebrates. They play a role both as predators and as prey for larger marine animals and are a target of commercial fisheries in several regions, where management measures have been implemented to address stock declines.

In summary, acanthias is a historical genus name linked to the spiny dogfish, but modern taxonomy places the primary species as Squalus acanthias, while the name Acanthias remains mainly of historical interest.