FRAGILARIA CAPUCINA DESM. VAR. MESOGONGYLA FRENGUELLI, A DIATOM DISTRIBUTED IN NORTHERN ZONE OF LOS ANDES MOUNTAINS (CHILE), WITH COMMENTS ON THE VARIABILITY OF THE NUMBER OF LABIATE PROCESSES IN SOME ARAPHID GENERA

Abstract

The diatom Fragilaria capucina var. mesogongyla, originally described by Frenguelli from Calama, Chile (22º28’S, 68º56’W), was found in a sample collected in the Lauca River, at high altitude in northern Chile’s (18º30’S, 69º16’W). For the first time, the taxon is studied by scanning electron microscopy (SEM). Unusual for the genus Fragilaria, this variety exhibits one labiate process on each valve pole (two per valve). An amended diagnosis is given, and photographs illustrate the principal morphological features of this taxon.