New phagotrophic euglenoid species (new genus Decastava; Scytomonas saepesedens; Entosiphon oblongum), Hsp90 introns, and putative euglenoid Hsp90 pre-mRNA insertional editing

Cavalier-Smith, T., Chao, E. E. and Vickerman, K. (2015) New phagotrophic euglenoid species (new genus Decastava; Scytomonas saepesedens; Entosiphon oblongum), Hsp90 introns, and putative euglenoid Hsp90 pre-mRNA insertional editing. European Journal of Protistology, 56, pp. 147-170. (doi: 10.1016/j.ejop.2016.08.002) (PMID:27718409)

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Abstract

We describe three new phagotrophic euglenoid species by light microscopy and 18S rDNA and Hsp90 sequencing: Scytomonas saepesedens; Decastava edaphica; Entosiphon oblongum. We studied Scytomonas and Decastava ultrastructure. Scytomonas saepesedens feeds when sessile with actively beating cilium, and has five pellicular strips with flush joints and Calycimonas-like microtubule-supported cytopharynx. Decastava, sister to Keelungia forming new clade Decastavida on 18S rDNA trees, has 10 broad strips with cusp-like joints, not bifurcate ridges like Ploeotia and Serpenomonas (phylogenetically and cytologically distinct genera), and Serpenomonas-like feeding apparatus (8–9 unreinforced microtubule pairs loop from dorsal jaw support to cytostome). Hsp90 and 18S rDNA trees group Scytomonas with Petalomonas and show Entosiphon as the earliest euglenoid branch. Basal euglenoids have rigid longitudinal strips; derived clade Spirocuta has spiral often slideable strips. Decastava Hsp90 genes have introns. Decastava/Entosiphon Hsp90 frameshifts imply insertional RNA editing. Petalomonas is too heterogeneous in pellicle structure for one genus; we retain Scytomonas (sometimes lumped with it) and segregate four former Petalomonas as new genus Biundula with pellicle cross section showing 2–8 smooth undulations and typified by Biundula (=Petalomonas) sphagnophila comb. n. Our taxon-rich site-heterogeneous rDNA trees confirm that Heteronema is excessively heterogeneous; therefore we establish new genus Teloprocta for Heteronema scaphurum.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Vickerman, Professor Keith
Authors: Cavalier-Smith, T., Chao, E. E., and Vickerman, K.
Subjects:?? 18S rRNA phylogeny ??
?? Biundula ??
?? Decastavida ??
?? Hsp90 phylogeny ??
?? Spirocuta ??
?? Teloprocta ??
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:European Journal of Protistology
Publisher:Elsevier
ISSN:0932-4739
ISSN (Online):1618-0429
Published Online:28 August 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in European Journal of Protistology 56:147-170
Publisher Policy:Reproduced under a Creative Commons License

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