A worldwide listing and biogeography of freshwater diatom genera: a phylogenetic perspective

Abstract

A listing of the accepted freshwater diatom genera worldwide is presented, indicating the distribution of the genera by continent. Out of a total of 249 genera, 63 (25%) of those genera are endemic to a single continent. The continent with the largest number of endemic genera is Asia, hosting 35 endemic genera. While Asia is also the continent with the most reported genera, a regression analysis showed there is no relationship between the continental richness of genera and generic endemism. Disjunct genera, those found on two continents, represent distributions found in other groups of organisms such as in higher plants, including North America-Europe, North America-Asia and Southern Hemisphere disjunctions. There are certain lineages of freshwater diatoms where the endemic genera are restricted to specific continents: both thalassiosiroid and cymbelloid diatoms have endemics in Asia, while eunotioids have endemics in South America. Future research is suggested combining distributions over space and time related to phylogenetic relationships of diatoms.

Valve ultrastructure of two species of the diatom genus Gomphonema Ehrenberg (Bacillariophyta) from Yunnan Province, China

“…The freshwater diatom genus Gomphonema Ehrenberg is a large genus of over 2400 described taxa (Kociolek et al 2019). The genus has been reported from every continent on earth (Kociolek 2016), including remote archipelagos such as Hawaii (Kociolek et al 2015a). It is known from fossil deposits dating back to the Eocene (Benson et al 2012), and from a wide range of fossil sites (e.g.…”

A new freshwater Gomphonema Ehrenberg (Bacillariophyta) species from Eastern Himalayas, India

“…Recently many novel taxa representing multiple lineages of diatoms were described from Asia, in particular, tropical Asia (Glushchenko et al 2019a, b;Thacker et al 2019;Liu et al 2019;Roy et al 2019;Kulikovskiy et al 2020). These discoveries confirm that Asia is the hotspot of diatom diversification as proposed by Kociolek (2019) and the same finding need to be strengthened using molecular phylogenetic tools.…”

Continental diatom biodiversity discovery and description in China: 1848 through 2019

“…Although there is tremendous described diversity in the continental diatom flora of China, and it is likely that there is still much to do to achieve a more comprehensive knowledge of that flora, the number of strains of continental diatoms in GenBank traceable to a source in China is modest. In fact, this is all the more surprising since some groups of continental diatoms have a tremendous diversity in China, and some endemic genera in Asia have representatives in the Chinese flora ( Kociolek 2019 ). Some of these groups include the Thalassiosiraceae and Cymbellales .…”

“…Many diverse lineages have originated, radiated and gone extinct in China. This is true for many groups of organisms, including continental diatoms (see Skvortzov 1937 ; Hustedt 1938a , b , 1939 ; Williams 2004 ; Williams and Reid 2006 ; Kulikovskiy et al 2012 , 2015 ; Hamsher et al 2014 ; Kociolek 2019 ).…”