Asteromphalus Parvulus Areolae Type

la. All hyaline rays of the same shape and width. . . Asterolampra, p. 133

lb. One of the hyaline rays narrower than the others

Asteromphalus, p. 133

Genus Asterolampra Ehrenberg 1844 (Plate 23, Table 29) Lectotype: Asterolampra marylandica Ehrenberg (vide Boyer, 1927, p. 71).

Synonym: Asterolampra vanheurckii Brun (vide Simonsen, 1974, p. 24). References: Ehrenberg, 1844a, pp. 73 and 76; Ehrenberg, 1844c, Fig. 10; Greville, 1860, p. 113; Wallich, 1860, p. 47, Plate 2, Fig. 5; Brun, 1891, p. 10, Plate 14, Fig. 1; Hustedt, 1930, pp. 485 and 489, Figs. 270, 271 and 274; Cupp, 1943, p. 68, Fig. 31. Asterolampra grevillei (Wallich) Greville and A. marylandica Ehrenberg are distinguished by the size of areolae and number of hyaline rays. Distribution: Warm water region (e.g., Mediterranean, Indian Ocean, Gulf of California).

How to identify: The species may be identified in valve view in water mounts.

Genus Asteromphalus Ehrenberg 1844

Lectotype: Asteromphalus darwinii Ehrenberg (vide Boyer 1927, p. 72). References: Ehrenberg, 1844b, pp. 198 and 200; Ehrenberg, 1844c, Figs. 1-7; Hernandez-Becerril, 1991a.

The genus encompasses 10 or more species commonly recorded from marine plankton. This chapter deals with a few distinct species and describes them as they are seen with LM.

Characters showing differences between species: Valve outline (variable in some species).

Number of hyaline rays (variable to a certain extent).

Position of central area (centric or eccentric).

Size of central area compared to valve diameter.

Shape of separating lines.

Shape of narrow hyaline ray within central area. Shape of areolated sectors. Size of areolae.

A. Valve outline oblong to elliptical: A. flabellatus and A. sarcophagus (Table 30).

A. marylandica

A. elegans

A. sarcophagus

PLATE 23 Asteroiampra marylandica, Asteromphalus parvulus, A. elegans, and A. sarcophagus. Valves with hyaline rays. Scale bar = 10 /xm.

TABLE 29 Morphometric Data of Asterolampra spp. (Hustedt, 1930)

Species

Diameter Valve areolae No. of (|i.m) in 10 )im hyaline rays

Size of central area

A. grevillei A. marylandica

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