A new species of Tovellia, T. aveirensis, is described on the basis of light (LM) and scanning electron microscopy (SEM) of motile cells and resting cysts, complemented with transmission electron microscopy (TEM) of flagellate cells and phylogenetic analysis of partial sequences of the large subunit ribosomal rRNA gene. Both vegetative cells and several stages of a life cycle involving sexual reproduction and the production of resting cysts were examined in cultures established from a tank in the University of Aveiro campus. Vegetative cells were round and little compressed dorsoventrally; planozygotes were longer and had a proportionally larger epicone. Chloroplast lobes were shown by TEM to radiate from a central, branched pyrenoid, although this was difficult to ascertain in LM. The amphiesma of flagellate cells had mainly 5 or 6-sided vesicles with thin plates, arranged in 5-7 latitudinal series on the epicone, 3-5 on the hypocone. The cingulum had 2 rows of plates, the posterior row extending into the hypocone and crossed by a series of small projecting knobs along the lower edge of the cingulum. A line of narrow amphiesmal plates extended over the cell apex, from near the cingulum on the ventral side to the middle of the dorsal side of the epicone. Eight or 9 narrow amphiesmal plates lined each side of this apical line of plates (ALP). Resting cysts differed from any described before in having numerous long, tapering spines with branched tips distributed over most of the surface. Most mature cysts showed an equatorial constriction. Neither cysts nor motile cells were seen to accumulate red cytoplasmic bodies in any stage of the cultures. The phylogenetic analysis placed, with high statistical support, the new species within the genus Tovellia; it formed a clade, with moderate support, with T. sanguinea, a species notable for its reddening cells.

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Freshwater woloszynskioid dinoflagellates were collected independently in Scotland and Portugal and found to belong to a previously unknown species of the genus Borghiella, here described as B. andersenii. The new species differs in morphology and nuclear-encoded LSU rDNA and ITS sequences from B. dodgei and B. tenuissima, the two species presently comprising the genus Borghiella. Unusual features of the new species were observed particularly during asexual reproduction, which took place in the motile stage -as in many other dinoflagellates -or in a so-called division cyst, recalling cell division in the family Tovelliaceae. Such diversity in cell division is rarely reported in dinoflagellates. Morphologically Borghiella andersenii differs from B. tenuissima in being only slightly compressed dorsoventrally whereas the latter species is flat. The slight compression is also visible in lateral view. Borghiella andersenii and B. dodgei are more challenging to discriminate but the apical structure complex is only half the length in B. andersenii compared with B. dodgei (3-4 vs 6 µm). This difference can only be accounted for in the scanning electron microscope. At the light microscopy level the epicone in B. andersenii is rounded whereas it is conical in B. dodgei. Sexual reproduction in Borghiella andersenii was homothallic by formation of planozygotes, followed by apparent resting cysts. Phylogenetic studies on woloszynskioids have recently shown that they comprise a polyphyletic assemblage, which has been divided into the three families Borghiellaceae, Tovelliaceae and Suessiaceae. New species of the three families are now being found rapidly in many parts of the world, proving that the techniques required to investigate these small, morphologically similar dinoflagellates are now in place and proving that such 'gymnodinioids' or 'woloszynskioids' comprise an often overlooked biological entity in both marine and freshwater biotopes. Based on LSU rDNA, B. andersenii is most closely related to B. tenuissima.