Leptosynapta dolabrifera

Leptosynapta dolabrifera, better known as the snot sea cucumber, is a small member of the class Holothuroidea and the family Synaptidae. Its closest relative is another species in its genus, Leptosynapta inhaerens, one of 34 species in the genus.

Description

This sea cucumber varies in size, ranging from 5 to 9 cm long. Its body is chubby and can be pink, purple, red, or white, often coated in mucus. Many lighter-colored individuals have translucent body walls. Small circular armored spines on its sides help it anchor itself and burrow into the seafloor.

It also has two to three toothed arms used for anchoring and extracting nutrients from the substrate. There are no differences between sexes. The thickness and length of the body can change depending on the amount of body wall muscle.

Distribution

The snot sea cucumber is found along the coasts of Australia, as well as in Portland, Oregon, and parts of Scotland. It prefers temperate, shallow waters.

Recent studies show an average density of 0.20 individuals per area. It is a favored food of the Eastern shovelnose stingaree, making up 4.7% of that ray's diet. As of 2021, the species is not considered endangered.

Habitat

Its habitat consists of nutrient-rich substrate—silty and fine in shallow areas, and dark, clay-like in deeper waters. Occasionally, it is found in rockier places, such as among coral skeletons in Edinburgh, Scotland.

Feeding and diet

Like most sea cucumbers, the snot sea cucumber burrows into sand or mud and uses its tentacles to extract nutrients. It feeds entirely by digging into the substrate and pushing it into its mouth with its anchors, leaving trails of sand as waste.

Sea cucumbers in the genus Leptosynapta can regenerate lost body parts through a process called morphallaxis, where remaining tissues redifferentiate to form a smaller but complete animal. If a piece includes both the mouth and part of the digestive tract, it can regenerate.

The digestive tract has three sections: the esophagus (connecting the mouth to the stomach), the stomach, and the intestine (between the stomach and anus). The stomach and esophagus are suspended in the dorsal mesentery, while the intestine is in the ventral mesentery. In the midsection, the digestive tract crosses the coelomic cavity at a point where the mesenteric attachment changes from dorsal to ventral—this is called the crossover point.