Echinocardium
Echinocardium is a genus of heart urchins, a group of irregular sea urchins. Heart urchins are named for their distinctive heart shape. They are found in a variety of marine environments, from shallow water to the deep sea, and are often found buried in sediment. They are typically 2-5 cm in diameter.
Common names
Echinocardium species are commonly known as "heart urchins" or "sand dollars." They are also known as "sea potatoes," "sea biscuits," and "cake urchins."
Characteristics
Echinocardium species have several distinctive characteristics:
- Heart-shaped body: They have a flattened, heart-shaped body with a pointed anterior end and a rounded posterior end.
- Five-rayed symmetry: Although their overall shape is asymmetrical, they exhibit a five-rayed symmetry, which is typical of echinoderms.
- Tube feet: Like other sea urchins, they possess tube feet, which are used for locomotion, feeding, and respiration.
- Spines: Their body is covered in spines, which vary in size and shape depending on the species.
- Aristotle's lantern: They possess a specialized feeding apparatus known as Aristotle's lantern, a complex structure of teeth and muscles used for scraping food off the seafloor.
Environments
Echinocardium species are found in a variety of marine environments, including:
- Shallow water: They are commonly found in sandy or muddy bottoms in shallow coastal waters.
- Deep sea: Some species are found in the deep sea, where they burrow into the sediment.
- Intertidal zones: Certain species can tolerate exposure to air during low tides, living in the intertidal zone.
References
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