2. 4. 2024

Species concepts for Charophytes – a battlefield with some hope for agreements

Prof. Dr. rer. nat. habil. Hendrik Schubert

(Institut für Biowissenschaften, Universität Rostock)

Připojte se online: meet.google.com/qhf-etyu-sna

Charophytes are located between the worlds: still being green algae, they share already many
features with the land plants, which evolved from them. Therefore, they are marvelous model
organisms for studying aspects of adaptation to terrestrial life style of plants. Nevertheless, they are
also puzzling for several reasons. Being phylogenetically very old, their recent appearance is probably
the result of many evolutionary bottlenecks they have passed. Some links between morphology and
ecological niche structure are striking, but still not fully understood, for example, it seems that the
most ancient members represent the most complex morphologies whereas modern forms are
simplified. Even more puzzling are the aspects of generative reproduction; morphologically complex
gametangia and still not fully understood life-cycles fuel debates about taxonomy of these groups for
more than half of a century without any compromise in sight.

The first part of the talk will introduce into charophytes, describing their morphology and
ontogenesis and briefly outline their ecological role and importance in order to form a sound basis
for understanding the problems with respect to species delineation.

The second part will remind the audience about the world of species concepts, explaining the
scientific basis for the recently accepted three basic horizontal as well as the phylogenetic approach.
With regard to the fact, that in practice pluralistic concepts are applied, the options and limitations
of the different concepts for charophyte systematics will be discussed, illustrated by examples. The
main focus will be “species delineation” and “lower taxonomic ranks” in order to address the still
ongoing debate about micro- vs. macrospecies concept.

The talk is thought as a supporting statement for application of the “species-are-hypothesis” concept
for charophyte taxonomy, hopefully pacing the way to case-specific agreements instead of
fundamental debates.

CV of the speaker HERE.