From: prl@csis.dit.csiro.au (Peter Lamb)
Subject: Re: Oahu wallabies (was Re: Logic and God)
Organization: CSIRO Division of Information Technology
Date: Fri, 4 Sep 1992 04:16:42 GMT

cjhs@minster.york.ac.uk writes:

>Seconded. Peter Lamb in particular went to a lot of trouble to check
>out the Oahu wallaby story, and I also looked up what references I
>could. As far as I am aware, the assertion frequently made in this
>group that the Oahu wallabies are incapable of interbreeding with their 
>Australian cousins is entirely supposition, and I would have thought it
>is a pretty unlikely supposition. (Disclaimer -- my opinion is that of
>a complete novice at biology; more informed guesses welcome.)

>The lack of feedback from the most knowledgeable contributors to
>talk.origins has been disappointing to me. I would still like someone
>who is a genuine expert on biology and evolution to check out the
>references and see precisely what can be claimed for these wallabies.
>Perhaps Chris Colby would be willing to check the references and give
>an informed opinion on what may be fairly claimed for the wallabies.

Yes, I'd have liked to see some more informed feedback, too, but
there's not all that much claimed for the wallabies in sources which
could be regarded as peer-reviewed biological journals.  The only thing
I could find is in the abstract to Lazell[2] (Lazell is the biologist
cited in the original Science Digest article).  Lazell simply states
"the taxonomic status of these animals is under study".

Unfortunately, I have so far been unable to locate copies of either
Lazell[1] or [5]. It is [1] that is probably the main source of the
information in the Science Digest article.

>However, in the absense of more informed input, I'll offer the
>following.  The Oahu wallibies are an interesting case of evolution in
>action, but calling it "observed speciation" is either inflated, or
>trivial.  It is true that the Australian and Oahu wallabies no longer
>interbreed; the pacific ocean is a very effective contracepive. This is
>the trivial claim, which does not give any weight to the real
>significance of the changes in the Oahu population.

I think that from what Lazell says in the BBC article[3], he is
probably personally convinced that speciation has occurred, but
that it does not yet have sufficient data to be a supportable
scientific claim.

> The stronger claim
>that they are incapable of interbreeding is untested.

Agreed. I have found absolutely no evidence that this test has ever been
carried out. Michele Smith (gms@vax.oxford.ac.uk) indicated that from her
experience in an Australian bio. research lab, performing the test legally
would be very difficult, as both Australia and Hawaii have strict import
restrictions on living animal material (including on semen).

>I have taken the liberty of including at this point a post which Peter
>Lamb made a while ago: this extract is a draft which he sent to me
>independently. Peter has put a lot of work into checking out this story.

I have now looked at [2,3,6] of the references I posted. I have not yet
been able to track down copies of the others. [6] does not deal in
detail with the Hawaiian wallabies, but does mention them. It does
mention another geographically isolated feral population of the same
species of wallaby (Petrogale penicillata penicillata; brush-tailed
rock wallaby) on an island off New Zealand, Kuaha(sp?). They were
introduced there in about 1870, and display some genetic differences of
about the same order of magnitude as those described for the Oahu wallabies.

There is one further point of interest in Lazell[3]:
	"Some Hawaiian moths began evolving into distinct species
	 just 1500 years ago, when Polynesians introduced new food
	 plants.
	 ... an African monkey (_Ceropithecus_ spp.) introduced to
	 St. Kitts in the West Indes possibly 300 years ago, which
	 appears to have developed anatomical differences to its likely
	 ancestor the vervet monkey _C._aethiops_.
	 Perhaps the most striking example of a natural population
	 evolving naturally is that of the medium ground finch
	 _Geospiza_fortis_, one of Darwin's Galapagos finches, which,
	 in response to a drought within the past 20 years, has evolved
	 a thicker bill to cope with a new diet."

>Felicitations -- Chris Ho-Stuart

Finally, the BBC article[3] is worth a look at if, like me, you
don't have a bio. background, but are interested in the wallabies and
just how different they are from the Australian species. It also
has an attractive full-page colour photo of one of the animals in question.
The article is longer, more informative, more recent and has a lower hype
content than the Science Digest one, and should probably be used as a
non-technical reference to these animals in preference to the Science
Digest article.

Justin Sanders (jsanders@phys.ksu.edu) chased up some more references to
the wallabies in Oz and in Hawaii:
js> On the variety of the parent stock in Australia-- genetic comparisons--

js> M.D. Eldridge et al. Cytogenetics and Cell Genetics, vol 48, p.228 (Part I)
js>         "            Genome, vol 32, 935 (Part II)
js>         "            Genome, vol 33, 798 (Part III)

The last of the Eldridge papers mentions the Oahu wallabies (but contains
no genetic comparisons of them with the Oz wallabies), and from
memory, one of them compares the Oz wallabies with their NZ cousins.

js> A short comment on the Oahu wallaby and its implications for preserving
js> endangered species by translocation is found in
js> S. Conant, Bioscience, vol 38, p254

The implications are obvious, I hope: if the population is too small and
the environment too different, you will end up preserving something rather
different from what you started with, and in quite a short time.

The Sharman paper[6] talks about suggested speciation mechanisms for
the native species in _Petrogale_.

Peter Lamb



[1] Lazell, J.D, "Strange rock wallabies of oahu. Fugitives from
	zoo were progenitors", Explorers J. 59(2), 1981, 66-67
[2] Lazell, J.D, T.W. Sutterfield and W.D. Giezentanner, "The population
	of rock wallabies (genus Petrogale) on Oahu, Hawaii",
	Biological Conserv, 30(2) 1984, 99-108
[3] Lazell, J.D, "Evolution on the hop", BBC (Br. Broadcasting Corp) Wildl,
	5(12) 1987, 666-668
[4] Lauret, M, "The distribution of the brush-tailed rock wallaby _Petrogale
	penicillata_, on Oahu", 'Elepaio, J Hawaiian Audubon Soc., 43(4), 1982,
	25-27
[5] Lazell, J.D, "Kalihi rock wallaby of Hawaii", Tigerpaper, UN-FAO, Bankok,
	7(2), 1980, 31-2
[6] Sharman, G. B, R. L. Close and G.M. Maynes, "Chromosome evolution,
	phylogeny and speciation of rock wallabies (petrogale, macropodidae)",
	Aust J Zool, vol 37(2-4) : 351 - 363(1990)
-- 
Peter Lamb (prl@csis.dit.csiro.au)
Newsgroups: talk.origins,sci.skeptic