la. Undulation of valve pronounced 2
lb. Undulation of valve evident but not pronounced 3
2a. A marginal strutted process on every second, occasionally on every interstria; valve without marginal chambers. . C. litoralis Lange & Syvertsen 2b. Marginal strutted processes grouped in pairs or triplets; valve with prominent marginal chambers covering three or four alveolus openings
C. stylorum Brightwell
3a. A marginal strutted process on every second to fourth interstria; valve with marginal chambers covering two alveolus openings
C. striata1 (KUtzing) Grunow in Cleve & Grunow
3b. A marginal strutted process on every third or fourth interstria; valve without marginal chambers C. caspia Grunow
C. caspia—northern temperate region, euryhaline.
C. litoralis—southern and northern temperate region, coastal, marine
(Lange & Syvertsen, 1989; Sancetta, 1990).
C. striata—northern temperate region, littoral.
C. stylorum—warm water region to southern temperate region, littoral. How to identify: The species may be identified with light microscopy (LM) as cleaned valves mounted in a medium of a high refractive index. Remarks: Nagumo & Ando (1985) made a comparative study of C. stylorum and a species identified as Cyclotella sp. The latter is most likely C. litoralis.
Genus Detonula Schutt ex De Toni 1894 (Plate 1, Table 2)
Lectotype: Detonula pumila (Castracane) Gran (vide Round et al., 1990, p.
Basionym: Lauderia pumila Castracane.
Synonyms: Schroederella delicatula Pavillard, Thalassiosira condensata Cleve (for other synonyms see Hasle, 1973a, p. 18).
1 Basinoym: Coscinodiscus striatus KUtzing.
Pervalvar axis (|j,m)
Marginal processes in 10 pun
Areolae in 10 |jun
D. confervacea D. pumila D. moseleyarta
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