Morphological and molecular characterization of the elusive vegetative stage of the diatom <i>Cerataulina</i> <i>bicornis</i>: a new record from Indian Sundarbans

Abstract The resting spore stage of Cerataulina bicornis has been reported sporadically from the Indian Sundarbans, with one sediment core record that dates back to ∼2000 yrs. BP, but its vegetative stage has remained elusive during this entire period. The present report of its vegetative stage is a new record from this estuarine system. A comprehensive morphometric description along with molecular data of rbc L and 18s rDNA of the vegetative stage of C. bicornis is presented. The morphological and morphometric characters observed in the light microscope (LM) and scanning electron microscope (SEM) studies, along with a detailed description of the copulae, establish its distinction from other Cerataulina spp. described from different parts of the world.