Robert A. Fensome

The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists

Abstract. This revision of the classification of unicellular eukaryotes updates that of Levine et al. (1980) for the protozoa and expands it to include other protists. Whereas the previous revision was primarily to incorporate the results of ultrastructural studies, this revision incorporates results from both ultrastructural research since 1980 and molecular phylogenetic studies. We propose a scheme that is based on nameless ranked systematics. The vocabulary of the taxonomy is updated, particularly to clarify the naming of groups that have been repositioned. We recognize six clusters of eukaryotes that may represent the basic groupings similar to traditional “kingdoms.” The multicellular lineages emerged from within monophyletic protist lineages: animals and fungi from Opisthokonta, plants from Archaeplastida, and brown algae from Stramenopiles.

Dinoflagellate phylogeny revisited: reconciling morphological and molecular based phylogenies

Ultrastructural and molecular phylogenetic data suggest that dinoflagellates diverged as a lineage possibly as early as the Precambrian. However, the fossil record is problematic before the Mesozoic. From the mid Triassic, though, the fossil record of dinoflagellates is a rich source of information on Mesozoic-Cenozoic dinoflagellates, especially the gonyaulacoids and peridinioids. From the sequence of appearance of species and tabulation types and the impression of early morphological experimentation and later stabilization, the early Mesozoic radiation of dinoflagellates appears to be a real evolutionary event: indeed, dinoflagellate morphology as we know it today may originate in that event. This would explain why it is so difficult to interpret earlier fossils as dinoflagellates. However, that the dinoflagellate lineage existed in some form in the pre-Mesozoic is supported by biogeochemical data, early results of which indicate that certain early Paleozoic acanthomorph acritarchs may belong to the lin...

Late Cretaceous and Cenozoic fossil dinoflagellates and other palynomorphs from the scotian margin, offshore eastern Canada

Synopsis Palynomorphs, especially dinoflagellate cysts (dinocysts), have been at the forefront of research carried out on Mesozoic‐Cenozoic sediments on the Scotian Margin over the last 30–40 years: this research has been driven by the need to develop a stratigraphical framework to better understand the regions petroleum systems. To support the compilation of a detailed event strati‐graphical scheme for the Late Cretaceous to Cenozoic of the margin, emphasising dinocysts but with information from other fossil groups and non‐biostratigraphical data, there is a need to formalise the dinocyst taxonomy. In this paper, we fulfill this need by illustratingand, where appropriate, describing and discussing taxa used in our event biostratigraphical scheme. The following taxa (dinocysts except where indicated) are new: Areoligeracircumsenonensis,Axiodinium,Axiodiniumprearticulatum, Cordosphaeridium delimurum, Glaphyrocysta extensa, Hafniasphaera delicata, Impletosphaeridium capitatum, Mendicodinium robustum (validation of previously proposed name), Minisphaeridium,Oli‐gokolpoma, Oligokolpoma tubulus, Palaeocystodinium obesum, Palaeocystodinium teespinosum, Palaeohystrichophora palaeoinfusa, Pentadinium sabulum, Pervosphaeridium granaciculare, Tall‐adinium, Wetzeliella caviarticulata and Cingutriletes tyriskos (a trilete spore). The following are newly proposed combinations (with a former name in parentheses): Cerebrocysta waipawaensis (Pyxidinopsis waipawaensis), Cerodinium glabrum (Cerodinium speciosum subsp. glabrum), Din‐opterygium alatum (Xiphophoridium alatum), Kleithriasphaeridium cooksoniae (Florentinia cook‐soniae), Kleithriasphaeridium perforatum (Florentinia perforata), Minisphaeridium latirictum (Hys‐trichosphaeridium latirictum), Nyktericysta tripenta (Balmula tripenta), Pentadinium granulatum (Pentadinium laticinctum subsp. granulatum) Talladinium? clathratum (Charlesdowniea clathrata) and Talladinium wulagenense (Charlesdowniea wulagenensis). Emendations of the following taxa are proposed: Apectodinium, Dinopterygium, Distatodinium, Glaphyrocysta, Hafniasphaera, Isa‐belidinium, Kleithriasphaeridium, Manumiella, Nyktericysta, Palaeocystodinium, Rhombodinium, Wetzeliella and Wetzeliella articulata. Material from the Kiowa Formation of Kansas supports our concept of Dinopterygium. We review several morphological terms already in the literature and introduce the following new ones: mesotabular, obtabular, contabular, penicontabular, epeliform, equi‐epeliform and lati‐epeliform.

Major transitions in dinoflagellate evolution unveiled by phylotranscriptomics

Significance We created a dataset of dinoflagellate transcriptomes to resolve internal phylogenetic relationships of the group. We show that the dinoflagellate theca originated once, through a process that likely involved changes in the metabolism of cellulose, and suggest that a late origin of dinosterol in the group is at odds with dinoflagellates being the source of this important biomarker before the Mesozoic. We also show that nonphotosynthetic dinoflagellates have retained nonphotosynthetic plastids with vital metabolic functions, and propose that one of these may be the evolutionary source of dinoflagellate bioluminescence. Finally, we reconstruct major molecular and morphological transitions in dinoflagellates and highlight the role of horizontal gene transfer in the origin of their unique nuclear architecture. Dinoflagellates are key species in marine environments, but they remain poorly understood in part because of their large, complex genomes, unique molecular biology, and unresolved in-group relationships. We created a taxonomically representative dataset of dinoflagellate transcriptomes and used this to infer a strongly supported phylogeny to map major morphological and molecular transitions in dinoflagellate evolution. Our results show an early-branching position of Noctiluca, monophyly of thecate (plate-bearing) dinoflagellates, and paraphyly of athecate ones. This represents unambiguous phylogenetic evidence for a single origin of the group’s cellulosic theca, which we show coincided with a radiation of cellulases implicated in cell division. By integrating dinoflagellate molecular, fossil, and biogeochemical evidence, we propose a revised model for the evolution of thecal tabulations and suggest that the late acquisition of dinosterol in the group is inconsistent with dinoflagellates being the source of this biomarker in pre-Mesozoic strata. Three distantly related, fundamentally nonphotosynthetic dinoflagellates, Noctiluca, Oxyrrhis, and Dinophysis, contain cryptic plastidial metabolisms and lack alternative cytosolic pathways, suggesting that all free-living dinoflagellates are metabolically dependent on plastids. This finding led us to propose general mechanisms of dependency on plastid organelles in eukaryotes that have lost photosynthesis; it also suggests that the evolutionary origin of bioluminescence in nonphotosynthetic dinoflagellates may be linked to plastidic tetrapyrrole biosynthesis. Finally, we use our phylogenetic framework to show that dinoflagellate nuclei have recruited DNA-binding proteins in three distinct evolutionary waves, which included two independent acquisitions of bacterial histone-like proteins.

The last 100 million years on the Scotian Margin, offshore eastern Canada: an event-stratigraphic scheme emphasizing biostratigraphic data

In order to provide a detailed stratigraphic framework for the Late Cretaceous and Cenozoic basin fill of the Scotian Margin (the continental shelf and continental slope off Nova Scotia, eastern Canada), we have developed an event-biostratigraphic scheme based mainly on new analyses of several exploration wells. These include the following shelf wells — Demascota G-32, Hesper I-52, Onondaga E-84 and Wenonah J-75 — as well as Shelburne G-29 and Shubenacadie H-100 on the slope. Several fossil groups are involved in this study, most notably dinoflagellate cysts (dinocysts) and nannofossils, with the former generally providing more diverse assemblages and the latter more precise calibration with global correlations. Because most of the material studied is from cuttings samples, we have relied largely on Last Appearance datums (LADs). The scheme incorporates information from about 250 microfossil species (or groups of species), delimiting about 180 events. Not all events occur in all wells and the scheme needs to be tested against future observations: nevertheless, it represents a considerable advance on previous schemes, which were based mostly on broad zones rather than detailed events. Moreover, it allows for a more refined assessment of ages of geological events, such as the early Eocene gamma spike and the incision of the Wenonah Canyon. And it provides an accurate age context for ongoing stratigraphic, sedimentological and paleoenvironmental studies, and ultimately for a fuller understanding of petroleum systems on the Scotian Margin. RESUME Pour fournir un cadre stratigraphique detaille du remplissage du Cretace tardif et du Cenozoique du bassin de la marge Neo-Ecossaise (plateau continental et pente continentale au large de la Nouvelle-Ecosse, est du Canada), nous avons mis au point une formule evenementielle-biostratigraphique principalement basee sur de nouvelles analyses de plusieurs puits d’exploration. Ces derniers comprennent les puits Demascota G-32, Hesper I-52, Onondaga E-84 et Wenonah J-75 sur le plateau continental ainsi que Shelburne G-29 et Shubenacadie H-100 sur la pente continentale. L’etude touche plusieurs groupes de microfossiles, plus particulierement les kystes de dinoflagelles (dinokystes) et les nannofossiles, les premiers procurant generalement des assemblages plus diversifies et les derniers, un etalonnage plus precis avec des correlations mondiales. Comme la majeure partie du materiel etudie provient d’echantillons de deblais, nous nous sommes largement appuyes sur les plans de reference des dernieres manifestations. La formule incorpore des donnees provenant d’environ 250 especes (ou groupes d’especes) de microfossiles delimitant quelque 180 phenomenes, dont environ 50 % sont bases sur des nanofossiles, quelque 46 % sur des palynomorphes et 4 % sur des foraminiferes. Les phenomenes en question ne se manifestent pas tous dans tous les puits et il faut encore soumettre la formule a des essais en vertu des observations futures: elle represente neanmoins un progres considerable par rapport aux formules anterieures, qui etaient surtout basees sur des zones etendues plutot que sur des phenomenes detailles. Elle permet de plus une evaluation plus raffinee des âges des phenomenes geologiques, comme les pics gamma du Paleocene tardif et l’incision du canyon Wenonah. Elle procure par ailleurs un contexte de datation exact pour les etudes stratigraphiques, sedimentologiques et paleoenvironnementales courantes, et elle permettra en fin de compte une comprehension plus complete des systemes petroliers le long de la marge Neo-Ecossaise. [Traduit par la redaction]

Abstract: A revised biostratigraphic and well-log sequence stratigraphic framework for the Scotian Margin, offshore eastern Canada

As part of a Play Fairway Analysis (PFA) of the Scotian Margin, offshore eastern Canada, we have conducted quantitative multi-disciplinary biostratigraphic studies of the Upper Triassic-Cenozoic sections in 6 wells: Bonnet P-23, Chebucto K-90, Cohasset L-97, Glenelg J-48, Glooscap C-63 and South Griffin J-13. These wells were chosen to provide good spatial coverage and stratigraphic penetration, plus correlation with the seismic grid. Using the results from these new wells as calibration, we have also evaluated pre-existing biostratigraphic data and interpreted the well-log sequence-stratigraphy of 14 additional wells using a consistent multi-disciplinary event scheme. Our study provides accurate ties and clarifies the origin of seismic horizons mapped across the area within the PFA project. Key to the dating of some horizons has been integration of the palynology and micropalaeontology (most commonly used for biostratigraphy on the Scotian Margin) with new nannofossil and available calpionellid data. By integrating the biostratigraphic, lithofacies, well log and seismic data, we have enhanced resolution over previous efforts and thus have a better understanding of unconformities and major flooding events in the region. Our component of the PFA should enable better targeting of hydrocarbon exploration efforts on the underexplored Scotian Margin, especially in deeper water..

A REVIEW OF SCRINIODINIUM KLEMENT 1957, ENDOSCRINIUM (KLEMENT 1960) VOZZHENNIKOVA 1967 AND RELATED DINOFLAGELLATE CYST TAXA

Abstract Specimens of the well known and distinctive Jurassic (typically Oxfordian) dinoflagellate cyst species Scriniodinium crystallinum from Australia and New Zealand vary from being nonparatabulate to paratabulate. Where present, the paratabulation, which is manifested by low parasutural ridges on the periphragm, shows a clear dextral torsion, indicating affinity with the gonyaulacacean subfamily Cribroperidinioideae. Other species of Scriniodinium, such as S. pharo and S. playfordii confirm that this genus unequivocally belongs in the subfamily Cribroperidinioideae. Scriniodinium and S. crystallinum are both emended in order to note the cribroperidinioid paratabulation. Endoscrinium, however, exhibits neutral torsion and thus belongs in the subfamily Leptodinioideae. Endoscrinium and its type, E. galeritum, are emended to note this paratabulation style. On the basis of this clear paratabulation difference between Scriniodinium and Endoscrinium, ten species are transferred to the most appropriate genu...

Wetzeliella and its allies – the ‘hole’ story: a taxonomic revision of the Paleogene dinoflagellate subfamily Wetzelielloideae

Fossil dinoflagellate cysts of the Paleogene peridiniacean subfamily Wetzelielloideae have a stable tabulation pattern similar to that of other fossil peridiniaceans, but distinguished by a four-sided (quadra) rather than a six-sided (hexa) 2a plate. Aside from tabulation, wetzelielloideans show great morphological variability, especially in ornamentation and horn development, but also in wall structure. This diversity has distracted attention from the morphological variation of the archeopyle, which, although always formed through loss of the 2a plate only, shows variations that we consider critical in unravelling the groups phylogeny. Important factors are the shape and relative dimensions of the archeopyle and whether the operculum is attached (adnate) or detached. These parameters allow us to define five archeopyle types: equiepeliform, hyperepeliform, hypersoleiform, latiepeliform and soleiform. Based primarily on archeopyle type and secondarily on wall morphology and ornamentation, we recognise six genera with an equiepeliform archeopyle, four with a hyperepeliform archeopyle, five with a latiepeliform archeopyle, five with a soleiform archeopyle and one with a hypersoleiform archeopyle. The earliest known wetzelielloideans, which occur around the Paleocene—Eocene boundary, have an equiepeliform archeopyle. Other archeopyle types evolved rapidly: taxa with hyperepeliform, latiepeliform and hypersoleiform types are known from the Ypresian. Latiepeliform and hyperepeliform types are restricted to the Ypresian and Lutetian. Forms with the soleiform archeopyle appeared in the late Lutetian, but were rare until the Bartonian, when they became the dominant type, and they were the only type in Priabonian and younger strata. Wetzelielloideans became extinct in the middle Oligocene. We make numerous taxonomic proposals, including the following new genera: Castellodinium, Dolichodinium, Epelidinium, Kledodinium, Michouxdinium, Petalodinium, Piladinium, Rhadinodinium, Sagenodinium, Sophismatia, Stenodinium, Stichodinium and Vallodinium. We emend the diagnoses of Charlesdowniea, Dracodinium and Wilsonidium, and erect the species Kledodinium filosum, Petalodinium sheppeyense and Sagenodinium franciscanum.

Karst-related outliers of the Lower Cretaceous Chaswood Formation, Maritime Canada: insights into terrestrial paleoecology and paleoclimate

The Lower Cretaceous Chaswood Formation is a terrestrial deposit preserved as scattered outcrops across Maritime Canada. Here we describe newly recognized outliers of the Chaswood Formation near Windsor, Nova Scotia. A Cretaceous age is confirmed only in Bailey Quarry, where sediments are provisionally assigned a Valanginian–Hauterivian (140–130 Ma) age based on palynology, making them among the oldest known deposits of the Chaswood Formation. At three nearby sites, putative Cretaceous sediments are recognized based on similar geological context, facies, and petrography; however, their age cannot be confirmed because sediments either lack palynomorphs or contain equivocal assemblages. Although the Chaswood Formation has been previously documented mainly in small tectonically generated basins, these new-found deposits are fluvial sands and gravels, and lacustrine or floodplain clays associated with a karstified gypsum surface developed on the Carboniferous Windsor Group. Deposits are preserved in karst val...

Hans Gocht (1930–2014)

![Figure][1] The leading German fossil dinoflagellate cyst researcher Hans Gocht passed away on the 24th of July 2014 during his 84th year. Hans had an outstanding career of over 40 years and made many breakthroughs, particularly in the field of dinoflagellate cyst morphology. He authored or co-authored around 50 publications, and was a modest, reserved and softly-spoken individual. His life was a remarkable one, especially for the tenacity he demonstrated in his rather unconventional transitions from artisan to laboratory technician and, finally, to mainstream science. Hans was born on the 16th of December 1930 at Ilmenau in Thuringia, eastern Germany. Unfortunately, he suffered a critical illness aged seven. He defied his doctor’s prognosis by recovering, but the effects stayed with him for the rest of his life. His father was imprisoned during World War II, and consequently the family were not well off. So the young Hans felt he should earn a living, and left school as soon as possible. … [1]: pending:yes