A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)

Background Gregarines are a group of early branching Apicomplexa parasitizing invertebrate animals. Despite their wide distribution and relevance to the understanding the phylogenesis of apicomplexans, gregarines remain understudied: light microscopy data are insufficient for classification, and ele...

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Main Authors: Timur G. Simdyanov, Laure Guillou, Andrei Y. Diakin, Kirill V. Mikhailov, Joseph Schrével, Vladimir V. Aleoshin
Format: Article
Language:English
Published: PeerJ Inc. 2017-05-01
Series:PeerJ
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Online Access:https://peerj.com/articles/3354.pdf
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author Timur G. Simdyanov
Laure Guillou
Andrei Y. Diakin
Kirill V. Mikhailov
Joseph Schrével
Vladimir V. Aleoshin
author_facet Timur G. Simdyanov
Laure Guillou
Andrei Y. Diakin
Kirill V. Mikhailov
Joseph Schrével
Vladimir V. Aleoshin
author_sort Timur G. Simdyanov
collection DOAJ
description Background Gregarines are a group of early branching Apicomplexa parasitizing invertebrate animals. Despite their wide distribution and relevance to the understanding the phylogenesis of apicomplexans, gregarines remain understudied: light microscopy data are insufficient for classification, and electron microscopy and molecular data are fragmentary and overlap only partially. Methods Scanning and transmission electron microscopy, PCR, DNA cloning and sequencing (Sanger and NGS), molecular phylogenetic analyses using ribosomal RNA genes (18S (SSU), 5.8S, and 28S (LSU) ribosomal DNAs (rDNAs)). Results and Discussion We present the results of an ultrastructural and molecular phylogenetic study on the marine gregarine Ancora sagittata from the polychaete Capitella capitata followed by evolutionary and taxonomic synthesis of the morphological and molecular phylogenetic evidence on eugregarines. The ultrastructure of Ancora sagittata generally corresponds to that of other eugregarines, but reveals some differences in epicytic folds (crests) and attachment apparatus to gregarines in the family Lecudinidae, where Ancora sagittata has been classified. Molecular phylogenetic trees based on SSU (18S) rDNA reveal several robust clades (superfamilies) of eugregarines, including Ancoroidea superfam. nov., which comprises two families (Ancoridae fam. nov. and Polyplicariidae) and branches separately from the Lecudinidae; thus, all representatives of Ancoroidea are here officially removed from the Lecudinidae. Analysis of sequence data also points to possible cryptic species within Ancora sagittata and the inclusion of numerous environmental sequences from anoxic habitats within the Ancoroidea. LSU (28S) rDNA phylogenies, unlike the analysis of SSU rDNA alone, recover a well-supported monophyly of the gregarines involved (eugregarines), although this conclusion is currently limited by sparse taxon sampling and the presence of fast-evolving sequences in some species. Comparative morphological analyses of gregarine teguments and attachment organelles lead us to revise their terminology. The terms “longitudinal folds” and “mucron” are restricted to archigregarines, whereas the terms “epicystic crests” and “epimerite” are proposed to describe the candidate synapomorphies of eugregarines, which, consequently, are considered as a monophyletic group. Abolishing the suborders Aseptata and Septata, incorporating neogregarines into the Eugregarinida, and treating the major molecular phylogenetic lineages of eugregarines as superfamilies appear as the best way of reconciling recent morphological and molecular evidence. Accordingly, the diagnosis of the order Eugregarinida Léger, 1900 is updated.
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spelling doaj.art-53afa53c66d443d1b1dc2d30f81c4fcb2023-12-03T10:50:54ZengPeerJ Inc.PeerJ2167-83592017-05-015e335410.7717/peerj.3354A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)Timur G. Simdyanov0Laure Guillou1Andrei Y. Diakin2Kirill V. Mikhailov3Joseph Schrével4Vladimir V. Aleoshin5Faculty of Biology, Department of Invertebrate Zoology, Lomonosov Moscow State University, Moscow, Russian FederationUMR 7144, Laboratoire Adaptation et Diversité en Milieu Marin, CNRS, Paris, Roscoff, FranceFaculty of Science, Department of Botany and Zoology, Masaryk University, Brno, Czech RepublicBelozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian FederationCNRS 7245, Molécules de Communication et Adaptation of Micro-organisms, Paris, FranceBelozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian FederationBackground Gregarines are a group of early branching Apicomplexa parasitizing invertebrate animals. Despite their wide distribution and relevance to the understanding the phylogenesis of apicomplexans, gregarines remain understudied: light microscopy data are insufficient for classification, and electron microscopy and molecular data are fragmentary and overlap only partially. Methods Scanning and transmission electron microscopy, PCR, DNA cloning and sequencing (Sanger and NGS), molecular phylogenetic analyses using ribosomal RNA genes (18S (SSU), 5.8S, and 28S (LSU) ribosomal DNAs (rDNAs)). Results and Discussion We present the results of an ultrastructural and molecular phylogenetic study on the marine gregarine Ancora sagittata from the polychaete Capitella capitata followed by evolutionary and taxonomic synthesis of the morphological and molecular phylogenetic evidence on eugregarines. The ultrastructure of Ancora sagittata generally corresponds to that of other eugregarines, but reveals some differences in epicytic folds (crests) and attachment apparatus to gregarines in the family Lecudinidae, where Ancora sagittata has been classified. Molecular phylogenetic trees based on SSU (18S) rDNA reveal several robust clades (superfamilies) of eugregarines, including Ancoroidea superfam. nov., which comprises two families (Ancoridae fam. nov. and Polyplicariidae) and branches separately from the Lecudinidae; thus, all representatives of Ancoroidea are here officially removed from the Lecudinidae. Analysis of sequence data also points to possible cryptic species within Ancora sagittata and the inclusion of numerous environmental sequences from anoxic habitats within the Ancoroidea. LSU (28S) rDNA phylogenies, unlike the analysis of SSU rDNA alone, recover a well-supported monophyly of the gregarines involved (eugregarines), although this conclusion is currently limited by sparse taxon sampling and the presence of fast-evolving sequences in some species. Comparative morphological analyses of gregarine teguments and attachment organelles lead us to revise their terminology. The terms “longitudinal folds” and “mucron” are restricted to archigregarines, whereas the terms “epicystic crests” and “epimerite” are proposed to describe the candidate synapomorphies of eugregarines, which, consequently, are considered as a monophyletic group. Abolishing the suborders Aseptata and Septata, incorporating neogregarines into the Eugregarinida, and treating the major molecular phylogenetic lineages of eugregarines as superfamilies appear as the best way of reconciling recent morphological and molecular evidence. Accordingly, the diagnosis of the order Eugregarinida Léger, 1900 is updated.https://peerj.com/articles/3354.pdfApicomplexaMarine gregarinesUltrastructureSSU and LSU rDNAEnvironmental DNA sequencesPhylogeny
spellingShingle Timur G. Simdyanov
Laure Guillou
Andrei Y. Diakin
Kirill V. Mikhailov
Joseph Schrével
Vladimir V. Aleoshin
A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)
PeerJ
Apicomplexa
Marine gregarines
Ultrastructure
SSU and LSU rDNA
Environmental DNA sequences
Phylogeny
title A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)
title_full A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)
title_fullStr A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)
title_full_unstemmed A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)
title_short A new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine Ancora sagittata (Leuckart, 1860) Labbé, 1899 (Apicomplexa: Eugregarinida)
title_sort new view on the morphology and phylogeny of eugregarines suggested by the evidence from the gregarine ancora sagittata leuckart 1860 labbe 1899 apicomplexa eugregarinida
topic Apicomplexa
Marine gregarines
Ultrastructure
SSU and LSU rDNA
Environmental DNA sequences
Phylogeny
url https://peerj.com/articles/3354.pdf
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