A new choanoflagellate species from Taiwan: Morphological and molecular biological studies of Diplotheca elongata nov. spec. and D. costata

A new species of acanthoecid choanoflagellate isolated from brackish waters of the Danshui estuary in North Taiwan has a mineralized lorica that consists of two chambers with a total length of 19–36 μm. It shares with Diplotheca costata the features of a posterior lorica chamber formed from broad and flattened costal strips and an anterior chamber with spatula-shaped costal strips. The new species has therefore been placed in the same genus and named Diplotheca elongata. A phylogenetic analysis of partial SSU rDNA sequences from Diplotheca costata and D. elongata supports this taxonomic affiliation. This is a large and distinctive choanoflagellate which has not been reported in any previous study, suggesting that it may be an endemic species of restricted distribution.