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INVERTEBRATES Machaeridia

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I've included here a UseNet post by Kenneth Kinman where he discusses the Promollusca (= Procoelomata) and the Machaeridea:


  From: Kenneth Kinman (kennethkinman@webtv.net)
 Subject: Re: Machaeridia, Wiwaxia, etc etc 
 Newsgroups: sci.bio.paleontology
 Date: 2002-03-25 13:16:34 PST 


Dear All,
      Class Machaeridea is part of Phylum Promollusca%.  I proposed this
new phylum in my 1994 book (The Kinman System).  Please note that the %
sign after the name Promollusca is not an error.  
        Attaching a percentage sign (%) to a name is a unique new
convention to show (within text) that a group is paraphyletic.  After
all, a paraphyletic group is just a part (percentage) of a total
holophyletic clade.  Some moderate cladists seem to like it, so I'm
going to be trying out this new convention in my classifications.
      Anyway, I followed Dzik in uniting the coeloscleritophorans,
halkieriids, and other groups into a Class Machaeridea, which as you can
see below is coded as a sister group to Phylum Mollusca.  I don't recall
if Dzik regarded chancelloriids as machaeridians or not, but I have done
so until it is shown they belong elsewhere.
      For the sake of clarity, I'll show the classification of
Promollusca% first, and then break down Class Machaeridea into Orders
down below that (just to make sure the columns line up right).   Then
I'll add a few closing notes.  By the way, Simon Conway Morris regards
Wiwaxia as a stem group annelid.


 Phylum Promollusca%
      1  Tullimonstrea
      2   Hyolithea
      B   Orthothecea
      3   Machaeridea
      4   {{Mollusca}}
      ?   Agmatea
      ?   Climactichnitea

Class Machaeridea
      1   Halkieriida
      ?   Chancelloriida (uncertain)
      2   Sachitida
      3   Tommotiida
      4   Turrilepadida
      5   Hercolepadida


     NOTES:  Class Machaeridea may also include Order Rhombocorniculida,
but they could be something else (as could Chancelloriida).  These are
extremely problematic fossil groups..  Perhaps that is why you usually
don't see them discussed or classified. 

 
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