Moestrup (1979: 82, figs 41–44)
Buck & Garrison (1983: 1264, fig. 26), Thomsen et al. (1990: 370, fig. 5)
Cells solitary. Lorica simple, Y-shaped, 25–60 µm long, comprising 7 costal strips, each to 8–10 µm long. Longitudinal costae 2, with no obvious crossing-over, twisting or spiralling, extending anteriorly to form 2 anterior spines to 37 µm long, and posteriorly to form a pedicel c. 25 µm long, comprising a single costal strip. Transverse costae absent. Protoplast ellipsoidal, 5–7 µm long. Flagellum 16–18 µm long.
Weddell Sea (Buck, 1981); New Zealand (Moestrup, 1979).
Bicosta antennigera shows no obvious twisting or spiralling of the longitudinal costae, a feature that distinguishes it from B. spinifera. The pedicel, composed of a single costal strip, also separates B. antennigera from B. spinifera and the closely allied B. minor (Reynolds) B.Leadb. (Buck & Garrison, 1983, fig. 7), both of which have a pedicel comprising 4 costal strips. Specimens examined by Manton et al. (1980) measured 40–80 µm long. One small specimen in the current study was 17 µm long.