Re: "Cetiformes" and Dinosauriformes

["Jaime A. Headden" <qilongia@yahoo.com>]

Ken Kinman (kinman@hotmail.com) wrote:

<Even though I am more of a lumper than a splitter (in general), in this case, 
I felt that there
was a definite possibility that whales could be polyphyletic (diphyletic).  
Therefore in my 1994
book, I split them into three separate Orders: Archaeocetiformes (7 families), 
Odontocetiformes
(17 families), and Mysticetiformes (6 families).   I coded them as a clade, and 
if its holophyly
can be clearly demonstrated, I would have no problem combining them into one 
Order "Cetiformes". 
I don't see any reason to use the spelling "Cetaciformes" (which I assume is 
based on a plural
form "cetacea" rather than the singular "cetus").  If there is a linguistic  
problem here, I would
like to hear it (but if it is just a phylocode thing, I am not going to give it 
much weight).

  I coded Order Mesonychiformes as sister group to the whale clade, but recent 
evidence clearly
shows that many (if not all) whales are closer to Order Artiodactyliformes.  
Therefore, as I said,
I plan to move Mesonychiformes up to show them as sister group to an 
artiodactyl-whale clade
(cetartiodactyls) and still assume that whales are probably holophyletic.>

  There is a big problem here with this set of codings: It ignores the nested 
diversity ofmost of
these taxa, and there is the constant assumption of monophyly or holophyly 
(splitting hairs) in
trying to have your cake and eat it, too....

  One, it ignores that odontocetes (physeterids, dolphins, and porpoises) and 
mysticetes (all
baleen whales) are closer to each other than either are to any of the 
archaeocetes. Two,
archaeocetes is not regarded by any recent worker on whale systematics as a 
valid group,
comprising as it is five different groups of radially arrayed taxa: 
Pakicetidae, Ambulocetidae,
Protocetidae, Basilosauridae, and Dorudontidae, each closer to modern whales 
than the first. The
last two form a group, Dorudontoidea. Your codings ignore the true diversity 
and pattern of
similarity. "Archaeocetes" is now used only to signify a group of 
whale-ancestors that are not
members of the extant whale clade (Odontoceti + Mysticeti) [some one refresh my 
memory if this has
been named]. This is irrelevant whether they are related more closely to 
mesonychians [I would
concur to them being polyphyletic] or artiodactyls. The clade Cetartiodactyla 
works even if
mesonychians are whale ancestors.
 
 --+--Mesonychidae
   `--Cetartiodactyla
      |--Cetacea
      |   |--Pakicetidae
      |   `--+--Ambulocetidae
      |      `--+--Protocetidae
      |         `--+--Dorudontoidea
      |            |   |--Dorudontidae
      |            |   `--Basilosauridae
      |            `--+--Odontoceti
      |               `--Mysticeti
      `--Artiodactyla (including hippos)

  So unless you have a valid reasoning to question the monophyly, I would 
suggest you try to test
the hypothesis. This serves science best.


=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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