Monoportula P.A.Sims & D.M.Williams

Williams, David M., Sims, Pat A. & Witkowski, Jakub, 2023, Notes on the rare Cretaceous species Syndetocystis uralensis Strelnikova leading to the description of a new monotypic genus Monoportula P. A. Sims et D. M. Williams nov. gen., Phytotaxa 595 (2), pp. 219-224 : 220

Monoportula P.A.Sims & D.M.Williams nov. gen.

Registration: http://phycobank.org/103661

Type species:— Monoportula uralensis (Strelnikova) P.A.Sims & D.M.Williams nov. comb.

Frustules cylindrical, valve face circular, flat. Valve face bordered by expanded marginal ridge separating it from vertical mantle. Areolae poroid, on valve face arranged in interrupted radial and sub-radial rows extending from off-centre hyaline area from which a stout spine extends. Scattered spinules cover valve face disturbing areolar arrangement. Mantle areolae in vertical rows situated between hyaline marginal ridge and hyaline valve margin. Mantle areolae covered by network of anastomosing costae. Internally areolae sunk in rows between hyaline ribs, areolae becoming more numerous towards valve margin. One (1) rimoportula present, its external opening through stout tube expanded at its summit, internally as slit between raised lips.