[Taxacom] Madagascar (was: Timetree of Life)

Wed May 18 16:30:44 CDT 2011

Hi Robin,

Monkeys can be a real pest in Africa and elsewhere - aggressive, agile, abundant, ecologically  flexible, and of course very smart. So the question: Why are they not on Madagascar or in Australasia? is a real problem. You've suggested possible reasons:

1. no opportunity. But they have been around for tens of millions of years. 
2. events (weather, floods, timing, etc.). There have been all sorts of events over that time.
3. low population when the time was propitious. There have always been lots of monkeys. 
4. any other reason or reasons you can think up. 

None of these seem very convincing (except perhaps 4!).

Michael

Wellington, New Zealand.

My papers on biogeography are at: http://tiny.cc/RiUE0

--- On Thu, 19/5/11, Robin Leech <releech at telus.net> wrote:

From: Robin Leech <releech at telus.net>
Subject: Re: [Taxacom] Madagascar (was: Timetree of Life)
To: "Michael Heads" <michael.heads at yahoo.com>, taxacom at mailman.nhm.ku.edu
Received: Thursday, 19 May, 2011, 9:07 AM

Michael,
That is rather like asking, "Why didn't something evolve this
way or that way?"
It could be:
1.  no opportunity.
2.  events (weather, floods, timing, etc.).
3.  low population when the time was propitious.
4.  any other reason or reasons you can think up.

Just as with people, "Why oh why didn't I take him up
on his offer for PhD studies?"  "Gee, I wish I had studied
more for this exam."

Horses used to be here in North America.  How come it took
the Spaniards to bring them back?  Why did North America
lose both the equids and camelids?  Why didn't they come back?

Robin

----- Original Message ----- From: "Michael Heads" <michael.heads at yahoo.com>
To: <taxacom at mailman.nhm.ku.edu>
Sent: Wednesday, May 18, 2011 2:56 PM
Subject: Re: [Taxacom] Madagascar (was: Timetree of Life)

Yes, but *why* haven't they gotten there?

Michael

Wellington, New Zealand.

My papers on biogeography are at: http://tiny.cc/RiUE0

--- On Thu, 19/5/11, Robin Leech <releech at telus.net> wrote:

From: Robin Leech <releech at telus.net>
Subject: Re: [Taxacom] Madagascar (was: Timetree of Life)
To: "Michael Heads" <michael.heads at yahoo.com>, taxacom at mailman.nhm.ku.edu
Received: Thursday, 19 May, 2011, 8:43 AM

Michael,
My Accam's Razor answer is that they haven't gotten there yet.
Robin

----- Original Message ----- From: "Michael Heads" <michael.heads at yahoo.com>
To: <taxacom at mailman.nhm.ku.edu>
Sent: Wednesday, May 18, 2011 2:23 PM
Subject: Re: [Taxacom] Madagascar (was: Timetree of Life)

Hi Ken,

Yes, but WHY exactly is it so difficult and rare for highly mobile animals such as primates, rodents, woodpeckers etc. to disperse to Madagascar? These groups have only one, one and no clades there, respectively. Very strange. Likewise, why have non-human primates never invaded Australasia? You suggest competitive exclusion for the absence of the rodent clades there but an introduced primate species (a macaque) is a 'weed' in west New Guinea. It seems that competition may explain why the pattern is preserved, but not how it originated in the first place.

Michael

Wellington, New Zealand.

My papers on biogeography are at: http://tiny.cc/RiUE0

--- On Thu, 19/5/11, Kenneth Kinman <kennethkinman at webtv.net> wrote:

From: Kenneth Kinman <kennethkinman at webtv.net>
Subject: [Taxacom] Madagascar (was: Timetree of Life)
To: taxacom at mailman.nhm.ku.edu
Received: Thursday, 19 May, 2011, 4:20 AM

Hi Michael,
Well, the lack of Hystricomorpha, Sciuromorpha, and various other
taxa in Madagascar would be most parsimoniously explained by the
difficulty and rarity of dispersal from mainland Africa to Madagascar.
It is probably largely by chance that lemur ancestors floated
over on trees. However, such dispersal is not so unlikely that I would
turn to a vicariance explanation for lemur origins. It seems extremely
unlikely to me that lorises and lemurs split before the K-T extinction.
----------Ken
P.S. The lack of certain rodent taxa in Australasia may be due to a
more complex combination of factors, but competitive exclusion is one
likely factor in such taxa attempting to island-hop into that area
(perhaps more so than the isolation afforded by the Wallace Line).
---------------------------------------------------------
Michael Heads wrote:
The trans-Atlantic pattern can be approached in the broader context
of the main rodent clades. It has to be explained together with
the fact that Hystricomorpha are not in Madagascar and are east
only to Borneo (cf. strepsirhines), while Sciuromorpha (squirrels) are
not in Madagascar and east only to Sulawesi (cf. haplorhines). Many
authors have commented on the absence of these groups from both
Madagascar and Australasia (cf. woodpeckers etc.). An
overall dispersal account for the rodents doesn't really explain
these interesting eastern limits in two of the three main rodent
groups, or their repetition in the primates and others.

_______________________________________________

Taxacom Mailing List
Taxacom at mailman.nhm.ku.edu
http://mailman.nhm.ku.edu/mailman/listinfo/taxacom

The Taxacom archive going back to 1992 may be searched with either of these methods:

(1) by visiting http://taxacom.markmail.org

(2) a Google search specified as: site:mailman.nhm.ku.edu/pipermail/taxacom your search terms here
_______________________________________________

Taxacom Mailing List
Taxacom at mailman.nhm.ku.edu
http://mailman.nhm.ku.edu/mailman/listinfo/taxacom

The Taxacom archive going back to 1992 may be searched with either of these methods:

(1) by visiting http://taxacom.markmail.org

(2) a Google search specified as: site:mailman.nhm.ku.edu/pipermail/taxacom your search terms here

_______________________________________________

Taxacom Mailing List
Taxacom at mailman.nhm.ku.edu
http://mailman.nhm.ku.edu/mailman/listinfo/taxacom

The Taxacom archive going back to 1992 may be searched with either of these methods:

(1) by visiting http://taxacom.markmail.org

(2) a Google search specified as:  site:mailman.nhm.ku.edu/pipermail/taxacom your search terms here