Brissidae

Characteristics

Brissidae sea urchins exhibit several distinctive characteristics that set them apart from other sea urchins:

• Heart-shaped test: The test is typically flattened and heart-shaped, with a distinct anterior end (front) and a posterior end (rear).
• Apical system: They have a well-developed apical system, consisting of the madreporite, genital plates, and ocular plates.
• Ambulacral plates: The ambulacral plates (plates bearing the tube feet) are often arranged in a pattern of two or three columns.
• Tubercles: The tubercles (bumps that support the spines) are small and numerous, and they are usually arranged in a regular pattern.
• Spines: The spines are short and often fine, and they are arranged in a dense covering over the test.

Environment

Brissidae sea urchins are found in a variety of marine environments, including:

• Shallow waters: They are common in shallow, sandy or muddy bottoms along coastlines.
• Deep waters: Some species inhabit deeper waters, often in association with coral reefs or rocky substrates.

They play an important role in marine ecosystems, feeding on detritus and sediment, which helps to maintain the health and stability of the seabed.

References

• World Register of Marine Species
• National Center for Biotechnology Information