Prof. John Endler on Endler's Livebearer
Richard Sexton
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Date: Mon, 17 Jul 95 14:40:57 PDT
From: end...@lifesci.lscf.ucsb.edu (John Endler)
To: ric...@interlog.com
Subject: for Richard Sexton
Cc: endler@lifesci
Richard J. Sexton
via ric...@panchax.gryphon.co
Dear Mr. Sexton,
A friend gave me a copy of your description of "Poecilia Endler's", and
I thought that you might like to know a little more about my namesake!
I discovered these fish in Laguna de Patos, near Cumana, northeastern
Venezuela in 1975. They had in fact been collected in 1937 by Franklyn
F. Bond, but I didn't know that at the time. (I found his collection in the
Museum of Zoology of the University of Michigan). They were found in warm
(27-30 degrees C) bright green and hard water in a small lake. The bright
metallic green is about the only thing that a prospective mate can see in this
very (unicellular) algae-rich water. Interestingly enough, a single
population of guppies that I found in southern Trinidad living in a similar
habitat was just starting to evolve the metallic green coloration, but it was
nothing compared to this species. The original stock was much more
polymorphic variable than the present one in the aquarium trade. I have also
long since lost the stock but it is supposed to be in the process of being
named by some people in Germany. I wanted them to call it Poecilia haskinsi
after Caryl Haskins, who knows more about wild guppies than anyone, and who
started me out studying these interesting species!
"Endler's Poecilia" got into the Aquarium trade via Klaus Kallman of the
New York Aquarium, who got it from the late Donn Eric Rosen, the major
taxonomic expert of the Poeciliidae, to whom I gave it so that he
could name it. Unfortunately he died before naming it. Klaus gave it to
aquarists and added the present common name ("Endler's Livebearer" or
"Endler's Poecilia") with out telling me (as a surprise), and I first
heard about it during a visit to England in the mid-1980's. It was quite
a surprise, but also a disappointment to see how much of the original
color pattern variation has been lost through inbreeding and founder
events. The wild fish are not always "double swordtails", have much more
variable color patterns, and some even have black pectoral fins. But
all have the lovely metallic green spots, though variable in size, shape,
and position. Although highly variable, the wild fish are not quite as
variable as wild guppies, though much more so than P. picta or P. parae--the
closest relatives. You mention their not having the "big triangular veil
tail", but wild guppies never have the veil tail either; veil tails are an
artifact of selective breeding.
"Endler's Poecilia" are not the same as guppies (Poecilia reticulata). One
of the first things I did when I found them in 1975 was to try to cross them
with wild guppies from a few kilometers away in Venezuela, as well as with
other wild stocks of guppies. Occasionally I would get F1 hybrids, but that's
all; they are clearly a distinct species. They live only in two sites in
Venezuela, one of them (Cumana) next to the city dump, so they might even be
extinct now in the wild. Someone should try to go back and check. The second
population I only heard about but was unable to find--at the base of the
Peninsula de Paria. The fact that they may be endangered makes me happy
that they are being kept by aquarists!
With best wishes,
John A. Endler
Professor of Biology
+------------------------------------------------------------------+
| Prof. John A. Endler |
| Department of Biological Sciences |
| University of California |
| Santa Barbara, California, 93106-9610 USA |
| tel: 1+ 805-893-8212 (office) fax: 1+ 805-893-4724 |
| tel: 1+ 805-893-8249 (lab) e-mail: end...@lifesci.ucsb.edu |
+---------------------------------------------------
--
Richard Sexton There is no Cabal
ric...@cabal.org