Pyramimonas robusta sp.nov., a new punctate species, and a reappraisal of the subgenus Punctatae

Abstract

The ultrastructure of a new punctate species, Pyrarrlirnonas robusta, is described and, by comparison with features of Pyrnrninlonns olivncea N. Carter and Pyran~irnorzas rnucifern Sym et Pienaar, has allowed for a more defined delimitation to the subgenus Punctntne McFadden. Features, in addition to the obvious character of puncta, which are considered characteristic of this subgenus, include a benthic nature, a chloroplast with a ventral groove coincident with the left and right sinuses, box scales with spines on their side walls, crown scales with eccentric crosses on their base plates, segmented T hairs, limuloid scales with three subsidiary spines and five subsidiary radial ribs, a 3-1 type flagellar apparatus, a basal body with a long region of triplets with longitudinal fibrils separating proximal and distal cartwheel structures, and a 3(2/1):4 or 3:3(2/1):2 microtubular root system. Although as a suite these are characteristic, a great deal of the individual features are shared with other subgenera, specifically subgroup 2 members of the subgenus Trichocystis McFadden but especially members of the subgenus Pyramirnonns McFadden. Features originally considered diagnostic that now are questionable include pyrenoid structure and starch investiture and the bilayered nature of the eyespot. Resum6: Les auteurs dtcrivent l'ultrastructure d'une nouvelle espkce de ponctuke, le Pyrarninzonns robusta et, par comparaison avec les caracteristiques du Pyrar~tit~~otlas olivacen N. Carter et du Pyramirnonas rnucifera Sym et Pienaar, sont conduits B mieux prCciser les dklimitations du sous-genre Punctatae McFadden. En plus des traits typiques desponctutes, les caracteristique considCrCes comme propres a ce sous-genre incluent la nature benthique, un chloroplaste avec une strie ventrale coyncidant avec les sinus droit ct gauche, Ccailles de la boite avec des Cpines sur les parois IatCrales, Ccailles de la couronne avec des croisements excentriques sur les plaques de base, poils en T segrnentCs, Ccailles limulo'ides avec trois Cpines subsidiaires et cinq c6tes subsidiaires radiales, un appareil flagellaire de type 3-1, un corps basal muni d'une longue rCgion de triplets avec des fibrilles longtudinales sCparant la partie proximale de la partie distale de l'appareil en roues de charette, et un systkme racinaire microtubulaire en 3(2/1):4 ou 3:3(2/1):2. Bien que comme ensemble ceux-ci soient caractCristiques, une bonne proportion de ces traits individuels sont partages avec d'autres sous-genres, spCcifiquement les men~bres du sous-group 2 du sous-genre Trichocystis McFadden mais surtout des rnembres du sous-genre Pyramintonas McFadden. Les traits qui Ctaient originalement considCrCs comme diagnostiques et qui sont devenus douteux, incluent la structure pyrCno'ide et la forme de l'amidon, ainsi que la nature en double couche de la tache visuelle.

Scaly green flagellates from Spanish Atlantic coastal waters: molecular, ultrastructural and pigment analyses

“…The maximum cell size of P. robusta was slightly greater than that given by Pienaar and Sym (1997) in the original description, but the morphology of the scales and the presence of puncta coincided. The average size of all scales observed was also somewhat greater than in the original description.…”

“…Additional spines were observed on the corners of box scale walls and their base plates were apparently not perforated. For crown scales, the framework of their base is not as flat as represented in Pienaar and Sym (1997). Furthermore, the color of the eyespot in strain CGA15 is yellow, as opposed to orange-red in the original description .…”