Morphological and Molecular Redefinition of Euplotes platystoma Dragesco & Dragesco‐Kernéis, 1986 and Aspidisca lynceus (Müller,1773) Ehrenberg, 1859, with Reconsideration of a “Well‐known” Euplotes Ciliate, Euplotes harpa Stein, 1859 (Ciliophora, Euplotida)

Abstract

We documented the morphology, infraciliature, silverline system, and molecular data of two euplotid species isolated from China, including two populations of the poorly known Euplotes platystoma Dragesco & Dragesco-Kernéis, and the previously well described Aspidisca lynceus (Müller, ) Ehrenberg, 1830. Based on the information available, an improved diagnosis of Euplotes platystoma is given, including: a narrow adoral zone with 44-68 membranelles, 10 frontoventral, 5 transverse, 2 left marginal and 2 caudal cirri, 11-13 dorsal kineties with 17-25 dikinetids in the mid-dorsal row, and dorsal silverline system of the double-eurystomus type. The Chinese population of Aspidisca lynceus closely resembles previously described populations. Phylogenetic analyses inferred from SSU rDNA sequences show that E. platystoma is closely related with E. neapolitanus, and the internal position of A. lynceus within this genus is still not robust. A reconsideration of the "well-known" Euplotes harpa and a comparison of all SSU rDNA sequences of E. harpa in GenBank are provided. We speculate that the sequences available from GenBank under the name of E. harpa are very likely from misidentified materials, that is, the identity of the species currently associated with the SSU rDNA of this "well-known" form in molecular databases requires further confirmation.

Symbionts of the ciliate Euplotes : diversity, patterns and potential as models for bacteria–eukaryote endosymbioses

“…Euplotes platystoma (some strains of which were previously misclassified as Euplotes harpa [46]) is more distantly related to all other clade B Euplotes species, and it is often sampled in low salinity rather than freshwater environments. Strain Fsp1.4 harbours Polynucleobacter [13], while strain Na2 is unique in clade B for harbouring a member of the genus Devosia (Alphaproteobacteria, Rhizobiales), 'Ca.…”

What Can Environmental Sequences Tell Us About the Distribution of Low‐Rank Taxa? The Case of Euplotes (Ciliophora, Spirotrichea), Including a Description of Euplotes enigma sp. nov.

“…The question mark after Euplotes harpa is due to recent reports suggesting that strains previously classified as E. harpa may actually belong to Euplotes platystoma (Lian et al. ; Yan et al. ).…”

“…; Lian et al. ), most of the molecular articles published between 2002 and 2012 released sequences assigned to various species without a morphological context. While there is no particular reason to mistrust these identifications, it is important that eventually at least one sequence per species is tied to a complete morphological characterization.…”

“…; Lian et al. ; Liu et al. ), many of the morphospecies of Euplotes are well defined by unique combinations of discrete and qualitative morphological characters that are supported by molecular data.…”

Next generation taxonomy: integrating traditional species description with the holobiont concept and genomic approaches - The in-depth characterization of a novelEuplotesspecies as a case study

“…As an example, some authors (Jones and Gates 1994) even proposed to synonymise almost all species possessing 10 FVC and a double dargyrome under the name of E. charon. Obviously, nowadays, this proposal is not acceptable on the basis of molecular data (Boscaro et al 2018;Lian et al 2018) and because of other morphological features characterizing some of the organisms (e.g. dorsal furrows/ridges, and body shape and proportions).…”