A-C = Cells on Skeletonema costatum (A,B,D = BF, C = PC) (arrow in C = base of horn parallel to pervalvar axis); D = Four cells (arrow = tightly coiled horns). A and B in Lugol, C and D living cells.
Life-form: Epiphytic on Chaetoceros, Skeletonema and others
Size: Apical axis = 4-12 µm, transapical axis = 2-3 µm
Resting spore: -
Note: This species has been confused with Attheya septentrionalis (Østrup) Crawford in the past
Distinctive features: Thin long horns initially parallel to the pervalvar axis and projecting up to 10 times the cell length
Similar species: Attheya septentrionalis
Distribution: Northern Atlantic
Crawford, R. M., Gardner, C. & Medlin, L. K. 1994. The genus Attheya. 1. A description of four new taxa, and a transfer of Gonioceros septentrionalis and G. armatas. Diatom Research. 9: 27-51.