The Evolutionary Origin of Animals and Fungi

Authors: Sandra Baldauf Maria Romeralo Martin Carr

Publish Date: 2013

Volume: , Issue: , Pages: 73-106

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Abstract

Animals and fungi make up the eukaryotic supergroup Opisthokonta along with a number of unicellular or “protistan” lineages We now know that some of these protists are specifically allied with animals and others with fungi making up the earliest branches of the eukaryotic superkingdoms that we now know as Holozoa and Holomycota The existence of these early diverging singlecelled animal and fungal sister taxa also confirms among other things that multicellularity arose independently in animals and fungi The opisthokont protists are vital keys to discover the common heritage of animals and fungi and to establish the baseline from which their unique and striking complexity arose Therefore there is a lot of current interest in understanding what these organisms are and how they are related to each other and the major groups of multicellular organisms The holozoan and holomycotan protists are also important links in defining the relationship of opisthokonts to the rest of eukaryotes In this chapter we describe all the major currently known groups of opisthokont protist what their distinguishing features are and what are our current ideas as to how they are related to each other Special attention is paid to the choanoflagellates as the most morphologically complex most diverse freeliving group of opisthokont protists and the sister group to Metazoa In order to understand early evolutionary groups it is also important to have a closely related outgroup Therefore we will also overview the Dictyostelia the only multicellular members of Amoebozoa currently the closest known sister group to opisthokontsWe would like to thank Barry Leadbeater for numerous helpful discussions and for careful reading of the manuscript We are also very grateful to Andreas Walberg and David Hibbett for advice on deep phylogeny of Metazoa and Fungi respectively and critical evaluation of Fig 73 Maria Romeralo was supported for part of this work by a postdoctoral fellowship from the Systematics Society of Spain and by EU Marie Curie grant PIEFGA2009236501 The work on Choanoflagellates was supported by a grant from the BBSRC UK

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