"Nereis" speciation event

Fournier, Judith JFOURNIER at mus-nature.ca
Tue Mar 26 22:38:00 EST 1996


The following is part of a message forwarded to Annelida:

 > 5.7 Speciation in a Lab Rat Worm, Nereis acuminata

 >      In 1964 five or six individuals of the polychaete worm, Nereis
 > acuminata, were collected in Long Beach Harbor, California.  These were
 > allowed to grow into a population of thousands of individuals.  Four
 > pairs from this population were transferred to the Woods Hole 
Oceanographic
 > Institute.  For over 20 years these worms were used as test organisms in
 > environmental toxicology.  From 1986 to 1991 the Long Beach area was
 > searched for populations of the worm.  Two populations, P1 and P2, were
 > found.  Weinberg, et al. (1992) performed tests on these two populations
 > and the Woods Hole population (WH) for both postmating and premating
 > isolation.  To test for postmating isolation, they looked at whether
 > broods from crosses were successfully reared.  The results below give
 > the percentage of successful rearings for each group of crosses.

Reading between the lines, it appears the researchers are dealing with some 
of the "Neanthes arenaceodentata" lab cultures first developed by Don Reish. 
 N. arenaceodentata is a New  England endemic but for many years the name 
was mistakenly applied to some west coast specimens.  Pesch et al (1988: 
Ophelia 28(2):163-167) showed that the Maine and California have different 
chromosome complements and cannot be the same species.   The use of the name 
"Nereis accuminata" for these specimens is probably invalid since this 
species was described by Day (1973) from North Carolina.   It is not a 
Californian species.   Neanthes caudata (delle Chiaje, 1828) as suggested by 
Hartman (1968) is a mediterranean speces.   One west coast species belonging 
to the "jaws like sand - group" is Nereis eakini Hartman.

This leads to 2 recommendations:

1.  A thorough review of the Nereis/Neanthes spp.  of California.

2.  Much more care in assigning names to populations -- cosmopolitan 
crypto-species seem to be more common than we thought.

It might also be a good idea to compare the Wood's Hole specimens to N. 
arenaceodentata from New England.

Judith A. Fournier
Canadian Museum of Nature
JFournier at mus-nature.ca



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