Peanut Worms, Sipunculid Worms
Photo: Chris Stephens
Called Peanut Worms or sipunculid worms, they are a small group of worm-shaped invertebrates in the Phylum Sipuncula. They differ from other worms in having a long tubular 'introvert' or proboscis which lies enrolled in the body cavity giving the animal an oval or peanut shape. When this introvert is in the body cavity it can be compared with the finger of a glove when it is tucked in the wrong way. Only when the worm is feeding or disturbed does the long tubular 'introvert' unfold from the body cavity. In the photo the introvert is the long tubular part of the animal on the right. Any good invertebrate book will give you more information on these animals. As far as molluscs are concerned they are the sole food of most species of the predatory snail family Mitridae.Authorship details
Rudman, W.B., 2000 (December 28) Peanut Worms, Sipunculid Worms. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/sipunculid
January 15, 2007
From: Matthew Rush
I am in the process of setting up a reef tank and have been cycling my live rock. Saw this guy in there today and I am trying to determine what he is and if he is something that will be safe to keep in the tank.
Locality: Oneida, Tank floor, NY, Reef tank, 12 January 2007, Hitchhiked on live rock. Length: 1-1.5 inches. Photographer: Matthew Rush.
firstname.lastname@example.orgRush, M., 2007 (Jan 15) Need ID help please. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19218
Since it looks quite slug-like I can give you a quick answer. It is a Sipunculid or peanut Worm. Shouldn't be a problem in your aquarium but may get eaten.
December 29, 2000
From: Chris Stephens
I received some live rock with a mysterious slug type hitch hiker and I wonder if you could id it. There are two of them, one much larger than the other.
Amazingly they survived the journey and are currently in a breeding trap in a sump tank.
email@example.comStephens, C., 2000 (Dec 29) Can you ID this ?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3197
I think this fits more into the 'worm' category rather than 'slug' category but as I've looked at your photo I'll add it to the Forum for reference.
It is a Peanut Worm or sipunculid worm, which are a small group of worm-shaped invertebrates in the Phylum Sipuncula. They are called peanut worms because that's what they usually look like. Only when they are feeding or disturbed does the long tubular 'introvert' which is on the right of your photo, unfold from the body cavity. Any good invertebrate book will give you more information on these animals. As far as molluscs are concerned they are the sole food of most species of the predatory snail family Mitridae.