Actinostephanus
Actinostephanus is a genus of sea urchins in the family Diadematidae. They are characterized by their distinctive radial spines, often with pointed or hooked tips, and their generally robust, dome-shaped tests. The genus includes several species, some of which are found in tropical and subtropical waters around the world.
Common Names
Common names for species within the genus Actinostephanus vary depending on location and language. Some common names include:
- Crown-of-thorns sea urchin (Actinostephanus longispina)
- Spiny sea urchin (Actinostephanus spinosus)
- Starfish urchin (Actinostephanus parvispinus)
Characteristics
Members of the genus Actinostephanus share several common characteristics:
- Spines: They have long, pointed, and often venomous spines that are arranged in a radial pattern around the test. These spines can be used for defense and to aid in movement.
- Test: The test, or shell, is typically robust and dome-shaped. It is covered in small, tubercles that give the test a rough texture.
- Tube feet: They possess tube feet, which are small, flexible appendages that are used for locomotion and feeding.
- Aristotle's Lantern: Like other sea urchins, they possess an intricate feeding apparatus known as Aristotle's Lantern, which is used to scrape algae and other food from surfaces.
Environments
Actinostephanus species are typically found in tropical and subtropical waters, inhabiting a variety of environments including:
- Coral reefs: Some species are common inhabitants of coral reefs, where they graze on algae and play a role in reef ecosystem dynamics.
- Rocky shores: Others are found in rocky intertidal zones and shallow subtidal areas.
- Seagrass beds: Certain species may also be found in seagrass beds.
References
For more information on Actinostephanus, refer to the following resources: