Multigene phylogeny and cell evolution of chromist infrakingdom Rhizaria: contrasting cell organisation of sister phyla Cercozoa and Retaria.

摘要: Infrakingdom Rhizaria is one of four major subgroups with distinct cell body plans that comprise eukaryotic kingdom Chromista. Unlike other chromists, are mostly heterotrophic flagellates, amoebae or amoeboflagellates, commonly reticulose (net-like) filose (thread-like) feeding pseudopodia; uniquely for eukaryotes, cilia have proximal ciliary transition-zone hub-lattices. They predominantly flagellate phylum Cercozoa and reticulopodial Retaria, whose exact phylogenetic relationship has been uncertain. Given even less clear relationships amongst cercozoan classes, we sequenced partial transcriptomes seven representing five classes endomyxan retarian Filoreta marina to establish 187-gene multiprotein phylogenies. Ectoreta (retarian infraphyla Foraminifera, Radiozoa) branch within classical as sister Endomyxa. This supports recent transfer subphylum Endomyxa from Retaria alongside which embraces retarians where capsules tests subdivide cells into organelle-containing endoplasm anastomosing pseudopodial net-like ectoplasm. more homogeneously filose, often pseudopodia and/or posterior gliding motility: zooflagellate Helkesimastix amoeboid Guttulinopsis form a strongly supported clade, order Helkesida. Cercomonads polyphyletic (Cercomonadida glissomonads; Paracercomonadida deeper). Thecofilosea whereas Imbricatea may not be; Sarcomonadea be paraphyletic. Helkesea Metromonadea successively deeper outgroups Monadofilosa; Reticulofilosa (paraphyletic on site-heterogeneous trees) branches earliest, Granofilosea before Chlorarachnea. Our trees confirm sisters infrakingdom Halvaria (Alveolata, Heterokonta) chromist subkingdom Harosa (= SAR); they further support holophyly Hacrobia, consistent Chromista Plantae. Site-heterogeneous rDNA group Kraken environmental DNA clade ‘eSarcomonad’, Paracercomonadida. Ectoretan fossil dates evidence ultrarapid episodic stem sequence evolution. We discuss early rhizarian evolution multigene tree coevolutionary patterns, gene-paralogue monophyly, integrate this the age eukaryote cells, revise classification.