Re: How old are the aroids?

**b* l* <l*@yahoo.com>**

Dear Christopher and all,

Aloha.

Wow. There must have been some sort of refugia all that time to preserve your geomorphic features for the habitat of your shrimp.  I would assume that is rare.  What is the geologic history of the sedimentation or other processes of the region?  Are we talking about Anostracan crustacea?  I know you wrote a paper on fairy shrimp in Minas Gerais...could you resend me the pdf off forum?...I seem to have lost that to virtual world.  Anostracans have a geologic history from the Lower Devonian, according to my Treatise on Invertebrate Paleontology.  I do not recall the age of your geomorphic features...could you refresh my poor memory? I am most familiar with the Santana formation fossils of the Late Cretaceous of Brazil...when shallow seas or lacustrine environments existed....and the connection to African fossils of similar age are proven.  I am assuming your geomorphic features predate that....perhaps by a significant period.

This is a very interesting point you bring up regarding tectonic movements and botanical evolutionary trends.  Are there many references on the biogeography of the aroids?  

Aloha,

Leland

--- On Wed, 7/30/08, Christopher Rogers <crogers@ecoanalysts.com> wrote:

> From: Christopher Rogers <crogers@ecoanalysts.com>
> Subject: [Aroid-l]  How old are the aroids?
> To: "'Discussion of aroids'" <aroid-l@gizmoworks.com>
> Date: Wednesday, July 30, 2008, 7:37 AM
> Hello Peter and Sin Yeng,
> 
>  
> 
> I understand your difficulties! I wrote a paper a few years
> ago revising a
> genus of freshwater shrimp. There are three species in the
> genus, all found
> in rain pools on a very specific geomorphic surface: one
> species in North
> America, one in South America, and one in Europe and north
> Africa. The
> geomorphic settings are all very old, and at one time
> before continental
> drift, were all near each other at the equator. Using this
> I could estimate
> the age of the genus. So here is my question: are any
> “primitive” aroid taxa
> limited to certain geomorphic features that can be traced
> through history?
> It may give you a means of estimating evolution rates for
> some higher taxa
> levels.
> 
>  
> 
> Grins,
> 
> Christopher
> 
>  
> 
>  
> 
> D. Christopher Rogers
> 
> Senior Invertebrate Ecologist/ Taxonomist
> 
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