Mallomonas vannigera Asmund

Kapustin, Dmitry A., 2024, An updated checklist of the silica-scaled chrysophytes from Russia, Phytotaxa 669 (3), pp. 165-193 : 182

162. Mallomonas vannigera Asmund

= Mallomonas vannigera var. parallelicosta Balonov , syn. nov.

Vologda region ( Balonov 1980c); Lake Baikal ( Volobyova et al. 1992; Bessudova et al. 2017) ; Republic of Buryatia ( Bessudova et al. 2018a) ; Irkutsk Region ( Bessudova et al. 2023f) ; Yaroslavl Region ( Kapustin , unpubl. data) .

Remark. M. vannigera var. parallelicosta differs from the type form by the presence of curved parallel ribs on the scale shield ( Balonov 1980c). However, M. vannigera var. vannigera may occasionally have a pair of short, curved parallel ribs posteriorly on the shield ( Nicholls 2001; Kristiansen 2002). Kristiansen (2002) also noted that ribs in M. vannigera var. parallelicosta are usually longer than in M. vannigera var. vannigera and almost all scales are marked with them. Our scanning electron microscopical observations showed that these ‘parallel ribs’ are actually the margins of a siliceous fold ( Figures 1–4 ). It seems that this fold is a teratology which does not have any taxonomic value.

Figures

FIGURES 1–5. Mallomonas vannigera and Synura macracantha from the Yaroslavl Region, SEM. Figs. 1–4. Scales of M. vannigera. Note the siliceous fold on the scales in Figs. 2–4. Fig. 5. Scales of S. macracantha. Scale bars: 1, 2, 4 – 1 µm; 3, 5 – 2 µm.