Turbellarian taxonomic database

Polychoerus carmelensis Notes

Costello HM, Costello DP 1938 (citation)- description of new species.
Costello HM, Costello DP 1938 (citation)-described copulation in this species and reproductive

Costello HM, Costello DP 1939 (citation)- described egg laying in this species.
Marcus E 1946 (citation)- discusses this in relationship to Macrostomidae, p 12.
Hyman LH 1951 (citation) - p 65 illustration of entire animal.
Costello DP 1960 (citation)- cytological details.
Costello DP 1960 (citation)- cytological details.
Costello DP 1960 (citation)- cytological details.
Costello DP 1961 (citation)- cytological details.
Armitage K 1961 (citation)- used this species in physiology experiments.
Ax P 1963 (citation)- descusses tails in this non-sand form- these may be sensory.
Dorjes J 1968 (citation)- lists.
Apelt G 1969 (citation)- p 268- notes Costello's observation of copulation in.
Costello DP 1970 (citation)- on order of chromosomes.
Henley C 1974 (citation)- p 268 notes Costello's observation on how rapidly they degenerate in lab- 
	only 6 hours in bucket of water.  p 270 - on reproduction in etc.  Review of Costello's 
	work.  Also observations not before published - p 286. etc. p 299 etc.
Dorjes J, Karling TG 1975 (citation)- Swedish Museum of Natural History.  California.
Tyler S 1976 (citation)- adhesive papillae in p 56.
Martin GG 1978 (citation)- on movement by ciliary gliding in.
Martin GG 1978 (citation)- rhabdites and ciliary gliding in.
Watzin MC 1984 (citation)- notes number of eggs and development from Costello p 324.

From Dr. John Pearse, 9-17-02:
Polychoerus carmelensis used to be very common and conspicuous in some of
the tide pools at both Carmel Point and Point Pinos on the Monterey
Peninsula. I often pointed it out to students during field trips in the
70s and 80s. Its presence at those sites was stricking because of its
absence along the Santa Cruz coast on the other side of Monterey Bay. I
always thought that had something to do with the different substrates on
the two sides of the Bay: granite on the Monterey Peninsula and mudstone
along the Santa Cruz coast. Several other taxa were also conspicuous in
their differences in abundance on the two sides of the Bay, brittle stars
in particular.

I thought I noticed a decline in the abundance of this worm in the 90s,
but there have been no quantitative studies. In 1993 I had my field class
document the species present at Carmel Point, and in 1994 they did the
same for Point Pinos. P. carmelensis was not recorded for Carmel Point,
but was listed as moderately abundant at Point Pinos. I find it difficult
to believe specimens were actually absent at Carmel Point, but that could
have been true.

I was at Carmel Point just last month, finalizing a transect for
intertidal monitoring, and I spent a few minutes looking for P.
carmelensis. I didn't find it. I'll be at both Carmel Point and Point
Pinos in the next month or so, and this time will make more of an effort
to find it.

I think there is no question that something is going on with the underrock
fauna in the intertidal around the Monterey Peninsula. Not only has there
been a major decrease in the abundance of P. carmelensis, but also for
brittle stars (especially Amphipholus squamata) and isopods (Cirolana
handfordi). Unfortunately, there have been very few quantitative studies,
none for P. carmelensis, so the decline is mainly anecdoctal.

I'll let you know what I find the next time I visit Carmel Point and Point

Update: 9-24-02
I spent a good deal more time at Carmel Point last Saturday, September
21st, looking in the tidepool that used to have lots of Polychoerus
carmelensis. Not a one and I am now pretty sure that the population is
gone. There were not many other familar underrock animals either, but
what seemed to be an unusual amount of diatom scuzz on the rocks and
algae. There was also quite a bit of a thick, slimy sponge, probably
Halisarca or Oscarella (introduced) that I don't recall seeing there
before. That sponge has been in our labs for over a decade, and is also
common in the Monterey Bay Aquarium. Whether it has anything to do with
the change we are seeing at Carmel Point is another matter.

Next spring I hope to have a bit more time to explore all the tidepools
around the Monterey Peninsula in search of P. carmelensis. If I can't find
it, we may have an extinction on our hands. Do you know of any records of
the species outside of those on the Monterey Peninsula?

Thanks for pushing me to follow-up on this perplexing change.


Note from Dr. Vicki Pearse on February 17, 2004: " On a low tide recently, we again found a few specimens of
Polychoerus at Pt. Pinos, under rocks.  So they are not extinct, though we are still so far unable to find
them at Carmel." 

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