A Globular Sea Urchin, known by its scientific name Mespilia globulus, is a type of sea urchin that exists in tropical shallow reef habitats. It’s also known as ‘Sphere Sea Urchin’ or ‘Tuxedo Urchin’.
The ‘globulus’ part of its name hints at its shape, which is like a small ball or spherule.
What Does a Globular Sea Urchin Look Like?
The Globular Sea Urchin is a fascinating creature with a unique appearance. Its body can reach up to 5 cm in diameter and has radial symmetry.
This means its body parts extend out in all directions from a central point, just like the spokes on a bike wheel.
Globular Sea Urchin has relatively small spines that can reach up to 2 cm in length. These spines can be brown, red, or dark in color.
What’s really cool about the Globular Sea Urchin is its body features ten vertical zones that are not covered in spines.
These zones are quite noticeable due to their vibrant shades of blue or green and have a velvety texture.
Where Can Globular Sea Urchins Be Found?
Globular Sea Urchins have a very wide distribution. They mainly live in shallow water reefs, coral rubble, and seagrass bed environments.
The Globular Sea Urchins are found at depths of up to 200 meters. Their preferred habitats are in the warm, tropical waters in the Indo-Pacific and Indian Ocean as well as the southwest coast of the western Pacific and Japan.
But Globular Sea Urchins are not just limited to these areas. They are found in most tropical environments near the equator, especially in coral reef and seagrass bed environments.
During the breeding season, Globular Sea Urchins are found in large numbers near the coast. Off-season, they migrate slightly away from the coast.
How Do Globular Sea Urchins Behave?
Globular Sea Urchins are mostly active during the night. During the day, they hide in the coral structure or rocks present in their habitat.
The Globular Sea Urchins feed in coral reef systems, seagrass beds, and fields of coral rubble by ‘grazing’. This means they eat organic material that has settled or is growing on the structure or on the sea floor.
Recent studies have shown that the presence of ‘grazing’ feeders like the Globular Sea Urchin can actually help corals survive and grow.
But too many urchins can limit the food available and affect their growth. They also try to camouflage themselves by sticking debris from their environment onto their bodies.
Are Globular Sea Urchins Used Commercially?
Yes, they are! Globular Sea Urchins are quite popular in the aquarium industry. They are often harvested and bred to be sold and put in recreational aquariums.
Globular Sea Urchins are loved for their vibrant colors and unique look. Plus, they are low-maintenance and generally don’t harm other organisms in the aquarium.
However, most of the sea urchins in the aquarium industry are wild-caught because breeding them in captivity is quite challenging.
How Do Globular Sea Urchins Reproduce?
Like all sea urchins, Globular Sea Urchins have separate male and female genders. Their breeding season is typically from July to September in the Pacific and Indian Oceans.
Fertilization is often external. This means the sperm and eggs are released into the water where fertilization takes place.
Sometimes, the eggs are held either on the peristome or deep into the concavities on the petaloid. This process, however, could be threatened by ocean acidification in the future.
Scientific Classification
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Order: | Camarodonta |
| Family: | Temnopleuridae |
| Genus: | Mespilia |
| Scientific Name: | Mespilia globulus |
| Also Known As: | Globular Sea Urchin, Sphere Sea Urchin, Tuxedo Urchin |
| Conservation Status: | Unknown |