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Re: feathers, hair and Compsognathus

>> It is ABSOLUTELY NOT useful to stick to the Linnean taxonomic rank of
>> "Reptile."  It is Doubly paraphyletic.  It is an awful example of Linnean
>> taxonomy.  Also, birds are defined cladistically as "All the descendants of
>> the most recent common ancestor of both Archaeopteryx and Corvis", and since
>> Sinosauropteryx does not fall within that clade, it is not a bird.
>     Not being up on my basal reptile phylogeny, could someone explain
>to me exactly why reptiles are now considered to be a paraphyletic
>group?  I assume this means that thier earliest common ancestor was NOT
>something that shared the traits that has caused scientists to group
>"reptiles" together.  What was this common ancestor, and how was it

Reptilia is paraphyletic if birds are excluded, since the ancestors of birds
were reptiles.

However, Reptilia is regarded by most systemicists today as a monophyletic
group: all descendants of the most recent common ancestor of turtles,
lepidosaurs, and archosaurs (including birds).

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661

"There are some who call me...  Tim."
-- Tim the Enchanter, "Monty Python and the Holy Grail"
---------- subtitle --[Monty Python ik den Holy Grailen]

"Tim?!?  They called me TIM?!?!"
-- Tom the Paleontologist, on seeing "The Ultimate Guide to T. rex" :-)