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Pellicle Ultrastructure Demonstrates That Moyeria Is a Fossil Euglenid

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Pellicle Ultrastructure Demonstrates That Moyeria Is a Fossil Euglenid This is a repository copy of Pellicle ultrastructure demonstrates that Moyeria is a fossil euglenid. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/165337/ Version: Published Version Article: Strother, P.K., Taylor, W.A., van de Schootbrugge, B. et al. (2 more authors) (2020) Pellicle ultrastructure demonstrates that Moyeria is a fossil euglenid. Palynology, 44 (3). pp. 461-471. ISSN 0191-6122 https://doi.org/10.1080/01916122.2019.1625457 Reuse This article is distributed under the terms of the Creative Commons Attribution (CC BY) licence. This licence allows you to distribute, remix, tweak, and build upon the work, even commercially, as long as you credit the authors for the original work. More information and the full terms of the licence here: https://creativecommons.org/licenses/ Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ Palynology ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/tpal20 Pellicle ultrastructure demonstrates that Moyeria is a fossil euglenid Paul K. Strother , Wilson A. Taylor , Bas van de Schootbrugge , Brian S. Leander & Charles H. Wellman To cite this article: Paul K. Strother , Wilson A. Taylor , Bas van de Schootbrugge , Brian S. Leander & Charles H. Wellman (2020) Pellicle ultrastructure demonstrates that Moyeria is a fossil euglenid, Palynology, 44:3, 461-471, DOI: 10.1080/01916122.2019.1625457 To link to this article: https://doi.org/10.1080/01916122.2019.1625457 © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group Accepted author version posted online: 30 May 2019. Published online: 22 Jul 2019. Submit your article to this journal Article views: 482 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tpal20 PALYNOLOGY 2020, VOL. 44, NO. 3, 461–471 https://doi.org/10.1080/01916122.2019.1625457 Pellicle ultrastructure demonstrates that Moyeria is a fossil euglenid Paul K. Strothera , Wilson A. Taylorb, Bas van de Schootbruggec , Brian S. Leanderd and Charles H. Wellmane aDepartment of Earth and Environmental Sciences, Weston Observatory of Boston College, Weston, MA, USA; bDepartment of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI, USA; cDepartment of Earth Sciences, Utrecht University, Utrecht, The Netherlands; dDepartments of Botany and Zoology, University of British Columbia, Vancouver, Canada; eAnimal and Plant Sciences, Alfred Denny Building, Western Bank, University of Sheffield, Sheffield, UK ABSTRACT KEYWORDS An earlier proposal of euglenid affinity for the acritarch Moyeria was based primarily on the pattern of acritarchs; Euglena; fossil bi-helical striate ornamentation as seen in scanning electron microscopy and light microscopy. algae and protists; Moyeria; Examination of specimens using transmission electron microscopy reveals that the ‘striae’ are actually Scotland; Silurian; USA integral components of the microfossil wall itself, corresponding to the pellicle strips of some euglenid species today. A Silurian specimen from Scotland preserves an articulated wall composed of thickened arches and thinner U-shaped interconnecting segments paralleling that seen in some modern photo- synthetic euglenids. A second specimen from the Moyeria holotype section (Silurian of New York State) shows fused articulation, again compatible with some extant euglenids. This evidence is suffi- cient to transfer Moyeria out of the Incertae sedis group, Acritarcha, and into the Euglenida. This pro- posal helps establish the morphological basis for the recognition of euglenid microfossils and ultimately provides evidence of a lengthy fossil record of the eukaryotic supergroup Excavata. 1. Introduction Moyeria uticaensis, but neglected to specify which of the four illustrated specimens was the holotype. Eisenack et al. (1976) In 1989, Jane Gray and Art Boucot posed the question, ‘Is considered Moyeria uticaensis to be a junior synonym of a Moyeria aeuglenid?’, in an article that explored the arguments striate acritarch originally described by Cramer (1971)as from morphology that supported the identification of the acri- Eupoikilofusa cabottii. Miller and Eames (1982) transferred E. tarch Moyeria Thusu 1973 as a fossil euglenid (Gray and cabottii to Moyeria and emended the genus description to Boucot 1989). Moyeria possesses a wall consisting of helically reflect the fact that the vesicle was not consistently fusiform arranged, parallel striae that converge at two opposite apical in overall shape, thus falling outside the morphological poles, and this feature is also found in the pellicle of many description of Eupoikilofusa. Most authors, including Gray extant euglenids. Gray and Boucot (1989) used scanning elec- and Boucot (1989), subsequently referred to helically striate tron microscopy (SEM) to document prominent striae in two OWMs with variably globular shape found in Ordovician and specimens from the Burvick Beds (Ludlow) in Sweden and Silurian rocks as Moyeria cabottii, retaining a genus name another three specimens recovered from the Tuscarora that was not validly published. Although this designation has Formation (Llandovery) in central Pennsylvania, USA. These not been the cause of any particular confusion, it is incorrect specimens also clearly demonstrated apical whirl reduction, a with respect to the rules of nomenclature (see Fensome character that is diagnostic of photosynthetic euglenids today et al. 1990 for a detailed explanation). (Leander and Farmer 2000;Leander2004; Leander et al. 2007). Thusu (1973, p. 142) specified the location coordinates of But Gray and Boucot (1989) were somewhat cautious in pro- the holotype on the original strew slide, and we have posing that Moyeria be identified systematically as a fossil located the original intended holotype specimen, which was euglenid, and never made any formal taxonomic recommen- illustrated in plate 2, figure 19 in Thusu (1973), and is con- dation. Subsequently, even though many authors have tacitly firmed as the holotype. We have also made an orthographic agreed with their conclusion, palynologists continue to refer correction to the original species epithet, uticaensis, which to Moyeria as an acritarch, i.e. an organic-walled microfossil now becomes uticana. This now validates the genus, (OWM) of unknown systematic affinity. Moyeria, and re-establishes M. uticana as its type species. We Moyeria was originally described by Bindra Thusu from an have also collected more material from the original section outcrop of Wenlock age exposed along the south branch of and have been able to further clarify the nature of M. uticana Moyer Creek, about 8 km west of the town of Ilion, New with respect to the more commonly used designation York, USA (Thusu 1973). He formally designated one species, M. cabottii. These are two distinct species, as we detail below. CONTACT Paul K. Strother [email protected] Department of Earth and Environmental Sciences, Weston Observatory of Boston College, 381 Concord Road, Weston, MA 02493-1430, USA ß 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Published online 22 Jul 2019 462 P. K. STROTHER ET AL. Figure 1. Location map for the Hagshaw Hills Inlier, Scotland (for more details see Wellman and Richardson 1993). Extant euglenids do not possess a cell wall in the conven- thinner tapering margin. Here we utilise the TEM to demon- tional sense; rather, their cells are enclosed by a protein- strate that the ‘striae’ in Moyeria possess an ultrastructure that aceous pellicle which lies inside the cell membrane (Leedale is fundamentally euglenoid in character. The articulated char- 1964). The pellicle itself consists of a series of parallel strips acter of the Moyeria wall has now been documented in two that are interlocked to each other along their margins. The independent Silurian specimens; one from the Hagshaw Hills pellicle strips may be laterally fused, to form a rigid structure, of the Scottish Midlands and another from the M. uticana or they may slide past each other allowing for euglenoid holotype section in New York State, USA. movement (Leander 2004; Leander et al. 2007, 2017). The strips, when isolated from each other in completely disrupted 2. Material and methods specimens and viewed by light microscopy (LM), have an optically thickened margin on one edge with a thinner flange Specimens of Moyeria were isolated from fresh rock collected in on the opposite margin (Leedale 1967, fig. 8), although the field by CHW (Fish Bed Formation; Figure 1)andbyPKS(the some strips may appear to be symmetrical, with two thick- Ilion Shale Member of the Lockport Formation and the Joslin Hill ened edges. When viewed by transmission electron micros- Member of the Herkimer Formation; Figures 2 and 3). Rock sam- copy (TEM) in transverse sections, pellicle strips exhibit four ples were cleaned and crushed and 40 g was demineralised main shapes as categorised by Leander and Farmer (2001):
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