PROTISTA - let's move on
kinman2 at YAHOO.COM
Tue Mar 7 22:06:03 CST 2006
Continuing from my post yesterday. The taxon Rhizaria (which I classify as a phylum) is holophyletic as far as I can tell. Bass et al., 2005 (Protista, 156:149-161) provide molecular evidence that the "core Rhizaria" (Foraminifera + Cercozoa) form a definite clade. And molecular evidence and some (admittedly weak) morphologically evidence earlier showed that radiolarians (except some heliozoans) belong to this clade as well. And Adl et al., 2005 also accept Rhizaria, so the nay-sayers seem to be pretty isolated on this one. By the way, isn't it refreshing that there is a journal called "Protista". I wonder if they would ONLY publish on non-Eumycotan fungal groups, as opposed to true fungi as well (I hope not). :-)
As for the Chromista, I am fully aware that some workers are very skeptical about its holophyly (including possible polyphyly). That is just one of many reasons I have always refused to recognize a separate Kingdom for chromists. Still, there is substantial evidence that Cryptophyta, Haptophyta, and Heterodonta, might form a holophyletic clade. However it turns out, I could always transfer Cryptophyta, or even Haptophyta, to other positions within Kingdom PROTISTA. Is there any strong data supporting such alternative positions (rather than clading together as Cavalier-Smith prefers)? If so, I will certainly seriously consider transferring them elsewhere in Protista. Otherwise, placing them separately in a huge polytomy is just an admission of ignorance and/or speculation.
P.S. As for the debate over whether Heterokonta or Stramenopila is a more appropriate name for that clade, I really could care less. Calling it one or the other (with the alternative as a common name) seems the best compromise. I should mention that in my 1994 classification, I also provided alternative standardized names for all protistan phyla (ending with the suffix -protista). Off hand, I've forgotten who originally suggested this standardized suffix for protist phyla, but would the name Stramenoprotista (common name: heterokonts) make most people happy as a compromise name for Phylum Heterokonta or Straminopila? Also, the name Dinoprotista would end the debate over Dinozoa vs. Dinophyta, as well as Euglenophyta vs. Euglenozoa, etc. :-)
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