Squaliformes
Squaliformes, commonly known as dogfish sharks, is an order of sharks belonging to the subclass Elasmobranchii. This order encompasses around 115 species, making it one of the most diverse groups of sharks. They are found in all oceans around the world, inhabiting a wide range of habitats from shallow coastal waters to deep-sea environments.
Characteristics
Squaliformes share several distinctive characteristics that set them apart from other shark orders. They typically possess elongated bodies with two dorsal fins, both of which are often equipped with spines. Their pectoral fins are positioned high on the body, and their pelvic fins are located further back. Dogfish sharks are also known for their distinctive gill slits, which are positioned laterally on their heads, as opposed to the ventral placement found in most other sharks.
Environments
Squaliformes exhibit a remarkable adaptability, thriving in various marine environments. They are found in both coastal and oceanic waters, ranging from the warm tropics to the frigid polar regions. Some species, such as the spiny dogfish (Squalus acanthias), are common in shallow coastal waters, while others, like the Greenland shark (Somniosus microcephalus), are found in the deepest, coldest parts of the ocean.
Common Names
The common name "dogfish shark" is derived from the elongated, dog-like appearance of some species. However, the order encompasses a wide variety of sharks, each with its own distinctive characteristics and common names. Some common examples include:
- Spiny Dogfish (Squalus acanthias)
- Greenland Shark (Somniosus microcephalus)
- Bigeye Sixgill Shark (Hexanchus vitulus)
- Cookiecutter Shark (Isistius brasiliensis)
- Sleeper Shark (Somniosus pacificus)
References
For further information on Squaliformes, consult the following reliable sources: