''Kaburakia excelsa'', the giant flatworm or giant leaf worm, is a species of

flatworm The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegment ...

found on the lower shore and shallow water in the eastern Pacific Ocean. It occurs on the lower shore and shallow sub-littoral zone.

Description

''Kaburakia excelsa'' can grow to a length of at least . It is flat and nearly as broad as it is long. It has a pair of fleshy nuchal tentacles on the anterior end of the body near where the brain is located. These tentacles can be retracted. On them and near their base are a number of simple eyespots, and there are more of these above the brain and a row of them round the margin of the body. The marginal eyespots are difficult to see in living specimens but the gut can be discerned through the skin and has the branching form typical of this order of flatworms. The upper surface is tan with a few darker brown streaks and spots while the underside is paler and largely unspotted. This species has no suckers on the underside. It can be distinguished from other flatworms in the area by its much larger size, and is in fact one of the largest flatworms in the world.

Distribution and habitat

This flatworm is native to the western seaboard of North America, its range extending from

Sitka russian: Ситка , native_name_lang = tli , settlement_type = Consolidated city-borough , image_skyline = File:Sitka 84 Elev 135.jpg , image_caption = Downtown Sitka in 1984 , image_size ...

in Alaska to Newport Harbor in California. It is found on the lower shore and in the shallow sub-littoral zone, under rocks, on pilings, on the fouled hulls of boats and among

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

s and rock-boring

bivalves Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

Ecology

The diet of this flatworm is not known, but it will eat mussels in the laboratory. It moves away from light, and as it moves, wrinkles form along the margins. In Washington State, breeding takes place in March, and in the laboratory, this flatworm has bred between June and August and in December. The eggs are golden yellow and enclosed in capsules. About 150 are laid, and are packed closely in one or two layers, forming an egg plate that is stuck to a rock surface. They hatch in five or more weeks at and the development of the offspring is direct. Newly hatched young are pale brown with five to seven eyespots. By a week later, they have darkened in colour, the front end becoming browner and the hind end becoming reddish.

References

{{Taxonbar, from=Q2465398 Rhabditophora Animals described in 1925 Fauna of the Pacific Ocean