Description
(Silicoflagellata Borgert 1890) by 0JVIND MOESTRUP The silicoflagellates sensu stricto are very common and important members of the marine plankton in many seas. When occurring in bloom conditions, they may cause mortality of fish , due to mechanical irritation of the fish gills by the spines of the skeleton (Fig . 1A) (Erardle Denn and Ryckaert , 1990). Numerous fossil repre- sentatives are known from the Cretaceous on- wards , peaking with more than a hundred spe- cies and varieties in the Miocene (Tappan , 1980) , but the number of extant species is probably limited to three (Moestrup and Thom- sen, 1990). These are readily identified as silicoflagellates because of the characteristic siliceous skeleton that surrounds the cell as a lateral bowl (Figs . 2A ,B) . Naked stages can be confused with raphidophytes but differ in the presence of only one long flagellum (Fig. 1 B) (van Valkenburg and Norris 1970 ; Moestrup and Thomsen 1990). Classification of the s iIi- coflagellates is blessed with many names. A p- parently the oldest class name is Silicoflagellata Lemmermann 1901 and the oldest order name Silicoflagellata Borgert 1890, p. 231. Borgert coined the term silicoflagellates. The extan t species are classified into a single
Type species
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Raw text
(Silicoflagellata Borgert 1890) by 0JVIND MOESTRUP The silicoflagellates sensu stricto are very common and important members of the marine plankton in many seas. When occurring in bloom conditions, they may cause mortality of fish , due to mechanical irritation of the fish gills by the spines of the skeleton (Fig . 1A) (Erardle Denn and Ryckaert , 1990). Numerous fossil repre- sentatives are known from the Cretaceous on- wards , peaking with more than a hundred spe- cies and varieties in the Miocene (Tappan , 1980) , but the number of extant species is probably limited to three (Moestrup and Thom- sen, 1990). These are readily identified as silicoflagellates because of the characteristic siliceous skeleton that surrounds the cell as a lateral bowl (Figs . 2A ,B) . Naked stages can be confused with raphidophytes but differ in the presence of only one long flagellum (Fig. 1 B) (van Valkenburg and Norris 1970 ; Moestrup and Thomsen 1990). Classification of the s iIi- coflagellates is blessed with many names. A p- parently the oldest class name is Silicoflagellata Lemmermann 1901 and the oldest order name Silicoflagellata Borgert 1890, p. 231. Borgert coined the term silicoflagellates. The extan t species are classified into a single