Synedrosphenia baculum (Gregory) Lobban & Ashworth comb. nov.

Synedra baculus Gregory, Trans. Micr. Soc. London, 5: p. 83, pl. 1, fig. 54, 1857. Based on GenBank sequence wk76 (Wiebe Kooistra). Basionym.

Registration.

Phycobank http://phycobank.org/103252.

Comment.

Since Synedrosphenia baculum (baton, rod) is used as a noun in apposition, it should retain its neuter ending, even though Gregory (1857) wrote it Baculus . This is an orthographical change that does not require any formal action under ICN rules, Art. 61 (Turland et al. 2018).

In addition, A. dalmatica ( Kützing) De Toni, 1892, shown by Álvarez-Blanco and Blanco (2014) to have a pseudoseptum and single wall, clearly belongs in Synedrosphenia . We have not made a new combination here, pending further investigation into its relationship to A. crystallina . Similarly, we do not have enough information to decide where to place Ardissonea brockmannii 'brockmanni ' Hustedt, 1932 (Hustedt 1931-1959, p. 228, fig. 716).