MSA - Systematics/Evolution
Spiegel, Frederick .
Slime molds everywhere - how their places in the Tree of Life have changed!.
In the 35 years since Olive’s, The Mycetozoans, our understanding of the slime molds, amoebae that make “fungus-like” sporulating structures, has changed markedly. I will present my overview of where we now stand with respect to slime molds that make standing sporulating structures. These are Olive’s Eumycetozoa and Acrasea. The former contained myxomycetes, dictyostelid cellular slime molds, and protostelids and was considered monophyletic. The latter contained the genera Acrasis, Pocheina, Guttulinopsis, Copromyxa, Copromyxella, and Fonticula and was thought to be polyphyletic. All “eumycetozoan” slime molds are members of the supergroup Amoebozoa; however, there is no strong evidence that they are monophyletic or that any of their subgroups are closely related to each other. Myxomycetes and dictyostelids are each monophyletic, but their respective traditional classifications are in need of substantial revision. The protostelids, or protosteloid amoebae, are found in at least seven distinct clades scattered throughout Amoebozoa. Some protosteloid amoebae are clearly members of traditional groups of “nonfruiting” amoebae. No protosteloid amoebae are clearly sibling groups of myxomycetes or dictyostelids. Revision of the “eumycetozoan” slime molds will involve revision of Amoebozoa. As expected, the acrasid cellular slime molds are polyphyletic, falling in at least three supergroups. Acrasis and Pocheina are heterolobosean members of Excavata. Acrasis is more species rich than previously expected. Work on Guttulinopsis is preliminary, but it is not heterolobosean. Copromyxa is in Tubulinea of Amoebozoa. Fonticula is a member of Opisthokonta and is sibling to the genus Nuclearia. Together, these two genera are sibling to Fungi forming a group we call Nucletmycea. Now that we have a reasonably complete concept of the places of the “classical” slime molds on the Eukaryote Tree of Life, it is truly possible to use comparative biology to address the origins of the fruiting habits of amoeboid eukaryotes.
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1 - University of Arkansas, Department of Biological Sciences, Science and Engineering 601, 1 University of Arkansas, Fayetteville, AR, 72701, USA
cellular slime molds
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood A/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 9:15 AM