Molpadida
Molpadida is an order of echinoderms belonging to the class Holothuroidea, commonly known as sea cucumbers. This order encompasses around 100 species, often referred to as “burrowing sea cucumbers” due to their characteristic burrowing lifestyle. Molpadida are distinguished by their elongated, worm-like bodies, typically lacking tentacles and exhibiting a distinct lack of calcareous ossicles (small, skeletal plates) within their body wall.
Common Names
Members of the Molpadida order are commonly known as "burrowing sea cucumbers" or "tail-end sea cucumbers," reflecting their unique body shape and burrowing behavior.
Characteristics
Molpadida are easily recognized by their elongated, worm-like bodies. Unlike most sea cucumbers, they lack tentacles and possess a distinct lack of calcareous ossicles in their body wall. Instead, they have a leathery, muscular body with a well-developed muscular ring around the anterior end, which aids in their burrowing activities. Their mouth is located at the anterior end, surrounded by a ring of small, fleshy papillae, which are used for feeding. Molpadida typically have a single, posterior anus and often exhibit bioluminescence, emitting light to deter predators.
Environments
Molpadida are found in a variety of marine environments, primarily in soft sediments, such as sand, mud, and clay. They are particularly common in shallow, coastal waters, but some species can also be found at greater depths. These burrowing sea cucumbers are found in tropical and subtropical waters globally.
References
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