Common Names
Diadematoid sea urchins are commonly referred to as long-spined sea urchins due to their distinctive long, sharp spines. They are also known as diadems, pencil urchins, and crown-of-thorns starfish.
Characteristics
Diadematoid sea urchins possess a number of defining characteristics:
- Long, sharp spines: This is the most prominent feature, offering protection from predators and aiding in locomotion.
- Five-part radial symmetry: Like all echinoderms, they exhibit a pentameral body plan.
- Test: Their rigid, calcareous shell (test) is covered with spines and pedicellariae (small pincer-like structures).
- Tube feet: They have numerous tube feet, which are used for movement, feeding, and respiration.
- Aristotle's lantern: This complex jaw structure is used for scraping algae and other food from surfaces.
Environments
Diadematoid sea urchins inhabit a range of marine environments, including:
- Coral reefs: Many species thrive in coral reef ecosystems, playing an important role in maintaining coral health.
- Rocky shores: They can be found in intertidal zones and on rocky substrates.
- Seagrass beds: Some species graze on seagrass, contributing to the diversity of these habitats.
- Deep sea: Certain diadematoid species inhabit deep-sea environments.
References
For further information and resources on Diadematoida, refer to the following websites: