Nereis (Neanthes) brandti (Malmgren, 1866)

Common name(s): Pileworm, Giant pileworm
Synonyms: Neanthes brandti
Phylum Annelida
 Class Polychaeta
  Order Phyllodocida
   Superfamily Nereidacea
    Family Nereidae
Nereis brandti (tentatively identified only by inspection) from Padilla Bay, WA.
This could be N. vexillosa instead.
(Photo by: Dave Cowles, July 2005)
Description:    As with all members of family Nereidae, this errant species has few if any segments longer than wide, even when contracted.  Its dorsal surface is not covered by paleae, elytra, or felt.  They have a pair of prostomialpalps which are differentiated into 2 units, the distal unit of which is smallest; and a pair of prostomial antennae.  Some of the setae are compound.  The evertedpharynx has 2 clearly delineated portions, with a large pair of jaws on the distal portion and usually with conical teeth on one or both portions.  Nereis brandti has conspicuous prostomial palps, 4 pair of peristomialtentacular cirri (which are not constricted into units), notopodia with aciculae + other setae, the ventral cirrus of all parapodia is simple, most of the paragnaths on the everted pharynx are conical,  notopodia of the posterior portion of the body do not have homogomphfalcigerous setae, the proximal ring of the everted pharynx usually has paragnaths in all areas, areas VII and VIII of the pharynx has a band of 4 or more rows of paragnaths, and the dorsal ligule of the parapodia is leaflike and much larger than the ventral ligule.  Juveniles have about 160 segments, adults about 230.  Up to 1 m long, occasionally to 1.5 m.

How to Distinguish from Similar Species:Nereis vexillosa is also frequently encountered.  N. vexillosa differs from N. brandti in that the upper ligule of the notopodia in the posterior body are strap-shaped.  It also does not grow as long as does N. brandti.

Geographical Range:  BC, Canada to southern CA, off Siberia

Depth Range:  Very low intertidal to subtidal

Habitat:  Buried deep in mud or sand

Biology/Natural History:  Predators include the Pacific staghorn sculpin Leptocottus armatus.  This species swarms as epitokes during spawning, and swarms have been observed during spring and summer in CA.  A close relative, Nereis virens, swarms about midnight in the dark of the moon during summer.  During swarming, males can be distinguished by the white sperm showing through the body wall, while the posterior segments of females are red due to the eggs inside.  In another relative, the Atlantic species Platynereis megalops, the females in a swarm bite off the posterior, egg-bearing segments of the swarming males.  After being swallowed and broken out of the male segments, the sperm pass through the wall of the female pharynx into her coelomic space, where they fertilize the eggs.  The fertilized eggs are shed through ruptures in the body wall.  The females do not shed their eggs until they are fertilized, and the eggs cannot be fertilized while free in the seawater.

Members of Family Nereidae seem to be very inefficient swimmers.  While swimming as while crawling, they undulate their bodies back and forth in metachronous waves.  While swimming these waves are of large amplitude and proceed from the back to the front of the animal (retrograde waves).  These waves produce a current which tends to move the animal backward.  At the same time, the frantic waving of the parapodia produces a current to drive the animal forward.  The result is that the animal doesn't go much of anywhere and mostly thrashes around.  The similar appearing Nephtys worms (Family Nephtyidae) use a much smaller metachronous body wave while swimming and can swim forward much more efficiently.

Nereids may be tubedwellers, mud borers, commensal, or free-crawling and free-swimming.  Nereis brandti is the largest polychaete worm on our coast.


 
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References:

Dichotomous Keys:
  Kozloff 1987, 1996
  Smith and Carlton, 1975 (as Neanthes brandti)
 

General References:

  MacGinitie and MacGinitie, 1949
  O'Clair and O'Clair, 1998
  Ricketts et al., 1985
  Sept, 1999

Scientific Articles:
 

Web sites:


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

July 27, 2005:  I observed a large Nereis, presumably Nereis brandti or Nereis vexillosa, swimming rapidly at the surface in calm, undisturbed water about 30 m offshore in Sharpe's cove, in water about 5-7 m deep.  The animal was at least 20 cm long and appeared to be longer because of a white stringlike substance that was attached to the posterior end.  Farther back the white "string" broke up into fragments that swirled away, and on closer inspection it turned out to be a white milky stream of material that appeared to be exuding rapidly from the posterior end of the animal.  I believe the animal was releasing a large quantity of sperm into the water.  The animal was swimming forward rapidly in nearly a straight line (heading approximately offshore), breaking the water's surface every 2-3 meters and swimming within 1/2 meter of the surface the rest of the time.  It was paddling vigorously with its parapodia and, though semicircular propulsive waves were passing back along its body, it was not writhing.  First inspection suggested that the animal was complete rather than an epitoke.  The time was about 6 pm, which was halfway on the flood tide cycle (tide height +5 feet), on the day of the half (waning) moon, and about 3 hours before sunset.  A lone individual spreading sperm in the upper water column seems to be pointless.  I wonder if this species has mating swarms around this time, like the palolo worm, and whether this individual was just a little early or late for the main swarm?  Perhaps I should examine the water at night and see if I can find more.  --Dave Cowles


Authors and Editors of Page:
Dave Cowles (2005):  Created original page