REPORT OF 2 SPECIES OF THALASSIOSIRA (BACILLARIOPHYCEAE) - THALASSIOSIRA-ROTULA MEUNIER AND THALASSIOSIRA-ANGUSTE-LINEATA (SCHMIDT,A) FRYXELL ET HASLE, AS NEW TO NORTHERN CHILE

Thalassiosira rotula Meunier and T. anguste-lineata (A.Schmidt) Fryxel l et Hasle are reported from samples collected in the north of Chile ( 20 degrees 48' S-70''11' W). T. rotula had not been previously reporte d from this area. The distribution of T. anguste-lineata in the South Pacific Ocean was known only from south of the 36 degrees 40' S. Using electron microscopy, the morphology of the frustules are described; i n the cingulum of T. anguste-lineata, a double septate valvocopula was observed.