General Description

Very small, roughly cylindrical to egg-shaped body; flat ventral sole; soft, thin to slightly leathery body wall; dark grey-brown; obvious tube feet ventral; two large anterior marsupia (brood pouches) with internal tube feet; 10 short dendritic tentacles, all anterior, ventral two smaller; ossicles absent or very rare branched/unbranched rods; up to 6 mm long, 3 mm high, 2.5 mm wide.


Incubocnus bimarsupiis, previously known as Neocnus bimarsupiis, is one of the smallest sea cucumbers in the world, with adults reaching a maximum size of 6 mm. It is dark and roughly egg-shaped with short bushy tentacles and relatively large ventral tube feet used to cling to its brown algal host. Sexes are not separate, and it is thought that this species is hermaphroditic or parthenogenetic. The anterior dorsal surface of adult Incubocnus bimarsupiis is dominated by a pair of marsupia (brood pouches) with minute internal tube feet. While exact methods are not known, it is thought that this species may use its two smaller ventral tentacles along with the internal tube feet to transfer eggs from the gonad to the brood pouch.


South-eastern Australia from Robe, South Australia to Cape Paterson, Victoria and north-east coast of Tasmania.


Reefs/Coastal shores. Attached to brown seaweed fronds (typically Zonaria angustata), rocky shallows, high wave energy parts of the south-eastern Australian coast, to depths of up to 6 m.

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