Peridinium volzii Lemmermann (1905: 166)

Bustamante-Gil, Carolina, Boltovskoy, Andrés, Rengefors, Karin, Tavera, Rosaluz, Amat, Eduardo & Ramírez-Restrepo, Jhon J., 2021, Checklist, new records, and taxonomic annotations of freshwater thecate dinoflagellate (Dinophyceae) in Colombia, Phytotaxa 509 (2), pp. 135-167 : 155-157

Peridinium volzii Lemmermann (1905: 166) . Figures 14–15

Synonyms:

Peridinium volzii var. australe in G. S. West (1909: 80)

Peridinium volzii var. maximum in C. Bernard (1909: 82)

Peridinium tabulatum in Playfair (1912: 542)

Peridinium guestrowiense in Lindemann (1916: 490)

Peridinium guestrowiense f. sinuatum in Lindemann (1919: 248)

Peridinium willei var. botanicum in Playfair (1919: 813)

Peridinium volzii f. sinuatum in M. Lefèvre (1932: 78)

Peridinium guestrowiense var. beta-collineatum in Lindemann (1920: 179)

Peridinium guestrowiense var. cyclicum in Lindemann (1920: 156)

Peridinium volzii f. cyclicum in M. Lefèvre (1932: 78)

Peridinium guestrowiense subvar. originale in Lindemann (1920: 158)

Dimensions: L: 47–69 µm, Td: 43–63 µm.

Cell shape: The theca is slightly polyhedral in young specimens and more rounded in those with wide sutural bands ( Figs. 14A–14C ). Epitheca and hypotheca of equivalent height. Descending cingulum (1-2).

Thecal characteristics: Tabulation, 4ʹ, 3a, 7ʹʹ, 5C, 6S, 5ʹʹʹ, 2ʹʹʹʹ ( Figs. 15F , 14G and 14H ). Bilateral symmetry in the arrangement of the plates, but not in their size. Cell lacking apical pore ( Figs. 14 and 15 ). The left anterior edge of the plate 1’ is usually shorter than the right edge. The apical 2ʹ is half the size of 4ʹ; exceptionally they are of equivalent size ( Figs. 14D, 14E and 14A ). The 2ʹ and 4ʹ plates are larger than those of the row 1a-3ʹ-3a ( Figs. 14D–14F ). The second intercalary plate (2a) is two times wider than longer ( Figs. 14E and 14F ). The 4ʹʹ plate touch anteriorly only the 2a plate ( Fig. 14F ). Antapical plates of similar size ( Fig. 14G ).

Cingulum and sulcus: The five cingular plates have intercingular sutures collinear with the sutures between the postcingular plates ( Fig. 14G ). The sulcus penetrates in the epitheca, slightly widening at the posterior end. The Sa plate has the typical shape for Peridinium with a main body and a left lobule. Ss plate is longer than the Sd plate. the left side of the Sp plate is higher than the right side ( Fig. 14H ).

Ornamentation: The surface reticulum of the sulcal plates is less conspicuous than that of the main thecal plates. The adcingular plates form cingular lists with radial ribs, less developed than in P. gatunense . Left margin of the sulcus bordered by a list originated in 1ʹʹʹ.

Localities: Chuza, San Rafael, Sisga, Neusa reservoirs, and La Tota lake in Central Colombia.

Comments: Specimens studied here were larger than the original description by Lemmermann (1905) and those reported previously in taxonomical studies ( Boltovskoy 1999a; Carty 2014; Cavalcante et al. 2017; Ling et al. 1989; Moestrup & Calado 2018) ( Table 8). The specimens from La Fe reservoir ( Fig. 15 ) differ from the nominal variety by the 1ʹ plate is taller and shortest anterior right edge, and some sulcal characteristics as follows: the anterior end of Sa plate penetrate deep into the epitheca, its Ss plate is notably longer and the two branches of the Sp plate do not differ in their length ( Fig. 15B ). Boltovskoy (1999a) discusses these differences between specimens and the possibility that they are different species. Teratological specimens with the two antapical plates fused together were found ( Fig. 15D ).

World distribution: Widely distribution in Europe, Asia, Oceania, and USA ( Moestrup & Calado 2018). In Central and South America, in Argentina ( Boltovskoy 1999a), Brazil ( Borics et al. 2005), Colombia ( Cardozo et al. 2005) and Costa Rica ( Hargraves & Víquez 1981).

Figures

FIGURE 14. Peridinium volzii. A Ventral view. B Dorsal view. C Lateral view. D, E and F Epithecal plates configuration.G Arrangement of the hypotheca and cingular plates. H sulcal plates. Bar=10µm.

FIGURE 15. Peridinium volzii, specimens from La Fe reservoir. A. Apical View.B Sulcal plates configuration. C Cell shape.D Hypotheca of teratologic specimen, fusion of antapical plates. Bar=10µm.