Laonome kroeyeri Malmgren, 1866

Common name(s): 

Synonyms:  Whole animal in tube
Phylum Annelida 
Subclass Palpata 
Order Canalipalpata 
Suborder Sabellida 
Laonome kroeyeri in its tube.  The tube is about 1 cm in diameter and 25 cm long.  This individual was caught by otter trawl at about 75 m depth in the San Juan Channel. 
(Photo by:  Dave Cowles, July 2008)
Description:   As with all members of family Sabellidae, most or all segments are at least as wide as long (photo); its surface is not covered by scales, paleae, elytra, or felt; it has featherlike radioles projecting from its head region like a feather duster (photo); and it lives in a secreted chitinous tube. Laonome kroeyeri has radioles whose main stems are not branched dichotomously.  Though they have ocelli scattered among the radioles (photo), these ocelli are not obvious and curled spirally around the radioles near their tips.  The first 5 or 6 thoracic neuropodia have uncini with short handles (not long handles) (photo).  The thoracic neuropodia have avicular uncini but no pickaxe-shaped setae (photo).  The uncini have broad bases.  The thoracic notopodia have both limbate and spatulate setae (photo).

How to Distinguish from Similar Species:Sabellastarte sp has only limbate or slightly spatulate setae on the thoracic notopodia and the uncini are almost S-shaped. Eudistylia spp such as Eudistylia vancouveri have some pickaxe-shaped neuropodial setae.

Geographical Range:

Depth Range:


Biology/Natural History:



Dichotomous Keys:
  Carlton, 2007
  Kozloff, 1987, 1996

General References:

Scientific Articles:

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors: 

Whole animal outside tube

This view shows the entire animal outside its tube.

Tip of tube

This closeup view of the tube shows how the tip of the tube (to the right) curls over and covers the end when the animal is not sticking out.

Ocelli on radioles

In this view the ocelli (dark spots) can be seen on the radioles.  The ocelli can sense light and dark, allowing the animal to pull rapidly inside its tube when a shadow passes over it.

In this view of the thoracic parapodia the neuropodia (above, directly facing the camera) can be seen to be short-handled, avicular uncini (or with no handles at all) that are in a straight or slightly sinuous line.  The notopodia (below) have both long limbate and shorter spatulate setae.  This is a view of the left side of the animal which is outside its tube.  The animal's ventral side (smooth, white) is up in this photo.

These two views show more detail of the thoracic setae.  The ventral neuropodia are in the left photo and the dorsal notopodia are in the right photo.
Thoracic neuropodia Thoracic notopodia
Thoracic neuropodia.  Head is to the top and ventral side is to the left.  The thoracic neuropodial setae consist of nearly straight avicular uncini with short or no handles.  The notopodia can be seen to the right. Thoracic notopodia (top).  The head is to the right and the dorsal side is on the top.  The thoracic notopodial setae consist of long limbate setae and shorter spatulate setae.  The neuropodia can be seen below the notopodia.

This view shows the ventral side of the animal's head.  Its mouth can be seen at the base of the radioles.

Juncton between thorax and abdomen

In this photo of the left side of the animal, head to the right and ventral side upward, the junction between the thorax and abdomen can be seen near the middle of the picture.  At the junction the dorsal notopodial setae (lower row) change from long limbate and spatulate setae on the thorax to short setae on the abdomen, while the ventral neuropodial setae (upper row) change from short avicular uncini to longer setae.


Ths view of the posterior end of the worm (left side) shows the pygidium.

Authors and Editors of Page:
Dave Cowles (2008):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)