MORPHOLOGICAL AND GENETIC VARIATION WITHIN THE DIATOM <i>SKELETONEMA COSTATUM</i> (BACILLARIOPHYTA): EVIDENCE FOR A NEW SPECIES, <i>SKELETONEMA PSEUDOCOSTATUM</i>¹

Abstract

ABSTRACT The nuclear gene encoding the small subunit (16S‐like) ribosomal RNA molecule was sequenced from four isolates of the marine coastal planktonic diatom Skeletonema costatum (Grev.) Cleve. Each isolate originated from a geographically separate water mass. Sufficient morphological and genetic differences were found among the four isolates to support the description of a new species, Skeletonema pseudocostatum , which corresponds to the CCAP 1077/7 and CS‐76 isolates.