Typification, valve ultrastructure, and systematic position of Gomphonema gomphopleuroides Amossé ex Kociolek, Glushchenko and Kulikovskiy, an endemic diatom from Southeast Asia

Abstract

Light and scanning electron microscope observations are presented on the diatom Gomphonema gomphopleuroides. This astigmate species, described originally from Vietnam, is large and robust, and has raphe branches that are shorter than in most other freshwater gomphonemoid diatoms. The uniseriate striae are unoccluded and the areolae are bordered by lunate ridges on one side, another unique feature of the species. Internally there is an apically elongated central nodule. This species is contrasted with the genus Gomphopleura, which also has shortened raphe branches. Gomphonema gomphopleuroides appears morphologically most similar to G. kaznakowi, a species endemic to southern China. The name G. gomphopleuroides is validated here with the designation of a neotype.

Keywords:

• diatoms
• Gomphonema
• Vietnam
• freshwaters
• morphology
• systematics

ACKNOWLEDGEMENTS

The authors are grateful to staff of the Russian-Vietnam Tropical Centre, Coastal Branch (Nha Trang, Vietnam) for their assistance in management and sampling. The work is the part of the project ‘Ecolan 3.2.’ of the Russian-Vietnam Tropical Centre. Publication is based on research carried out with financial support by Russian Science Foundation (14-14-00555).

Disclosure statement

No potential conflict of interest was reported by the authors.