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graptolite classification




In my 1994 book, I placed graptolites and pterobranchs together in Class Pterobranchea, separate from acorn worms (Class Enteropneustea).
And my preliminary cladistic coding of Class Pterobranchea shows living pterobranch groups nested well within the graptolites. I show one living clade (Rhabdopleurida + Graptovermida + Cephalodiscida), with three successive graptolite outgroup clades. The graptolite Order Dendroida managed to hold on until the Upper Carboniferous, leaving only the two living orders of pterobranchs during the Mesozoic and Cenozoic.
And by the way, all four clades of Pterobranchea have their origins in the Cambrian. And as of 1994, the living Order Rhabdopleurida was known back to M. Cambrian, and the living Order Cephalodiscida was known back to Lower Ordovician, but both are in the same clade.
My two cents worth,
Ken Kinman
*********************************************************
From: NJPharris@aol.com
Reply-To: NJPharris@aol.com
To: ELurio@aol.com, qilongia@yahoo.com, dinosaur@usc.edu
Subject: Re: *Longisquama* and Fossil "Ghost" Lineages -- Rehashing an Old Debate
Date: Mon, 26 Jun 2000 21:09:27 EDT


In a message dated 6/26/00 5:59:02 PM Pacific Daylight Time, ELurio@aol.com
writes:

> The last common ancestor of grapholites and Cephalodiscus was the Ordovican
> at least.


Unless _Cephalodiscus_ could be shown to nest within the graptolites, that
is.  But this does not appear to be the case, from what's been said on the
list...

Nick P.
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