ABCDEFGHIJKLMNOPQRSTUVWXYZ

Authority

(Bréb.) Ralfs, in Pritchard (1861: 838, pl. 8, fig. 21)

Class

Diatomophyceae

Order

Centrales

Family

Asterolampraceae

Synonyms

Spatangidium ralfsianum G.Norman (1859: 161, pl. 7, fig. 7)
Asterolampra heptactis (Bréb.) Grev. (Greville, 1860: 122), as hepacticus
Asterolampra ralfsiana (G.Norman) Grunow (1876), in Schmidt et al. (1874–1959: pl. 38, figs 5–8)
Asterolampra areolata A.Mann (1925: 30, figs 5, 6)

top

Basionym

Spatangidium heptactis Bréb. (Brébisson, 1857: 296, pl. 3, fig. 2)

Additional References

Boden (1985: 29), Priddle & Fryxell (1985: 116, figs A, E), Ricard (1987: figs 54–57), Andreoli et al. (1995: 472, fig. 5)

Description

Cells solitary, discoid. Valves slightly convex, 42–175 µm diameter; central hyaline area occupying c. 25–33% of valve diameter; 7 hyaline rays, one markedly narrower than the others, extending from centre almost to periphery of valve and ending in a protruding tubular process. Separating lines within central area bent or branched. Peripheral sectors areolate; areolae in tangential lines, 5–7 in 10 µm, 3 in 10 µm towards the centre.

Distribution

Typically found in temperate waters (Hasle & Syvertsen, 1997); Southern Ocean (Priddle & Fryxell, 1985); Ross Sea (Watanabe, 1982; Andreoli et al., 1995); Bransfield Strait (Priddle, 1985).

Comments

Priddle & Fryxell (1985) noted the difficulty in distinguishing A. heptactis from A. parvulus (see below), although the latter generally has a smaller valve diameter (22–48 µm).

top