Bibliographic Detail
Thessen, A.E., Patterson, D.J. & Murray, S.A., 2012
Reference:
Thessen, A.E., Patterson, D.J. & Murray, S.A. (2012). The taxonomic significance of species that have only been observed once: The genus Gymnodinium (Dinoflagellata) as an example. PLoS ONE 7(8): e44015 [1-34], 7 figures, 2 tables.
Publication Date:
August 2012
Notes:
doi:10.1371/journal.pone.0044015
Abstract:
Taxonomists have been tasked with cataloguing and quantifying the Earth's biodiversity. Their progress is measured in
code-compliant species descriptions that include text, images, type material and molecular sequences. It is from this
material that other researchers are to identify individuals of the same species in future observations. It has been estimated
that 13% to 22% (depending on taxonomic group) of described species have only ever been observed once. Species that
have only been observed at the time and place of their original description are referred to as oncers. Oncers are important
to our current understanding of biodiversity. They may be validly described species that are members of a rare biosphere, or
they may indicate endemism, or that these species are limited to very constrained niches. Alternatively, they may reflect that
taxonomic practices are too poor to allow the organism to be re-identified or that the descriptions are unknown to other
researchers. If the latter are true, our current tally of species will not be an accurate indication of what we know. In order to
investigate this phenomenon and its potential causes, we examined the microbial eukaryote genus Gymnodinium. This
genus contains 268 extant species, 103 (38%) of which have not been observed since their original description. We report
traits of the original descriptions and interpret them in respect to the status of the species. We conclude that the majority of
oncers were poorly described and their identity is ambiguous. As a result, we argue that the genus Gymnodinium contains
only 234 identifiable species. Species that have been observed multiple times tend to have longer descriptions, written in
English. The styles of individual authors have a major effect, with a few authors describing a disproportionate number of
oncers. The information about the taxonomy of Gymnodinium that is available via the internet is incomplete, and reliance on
it will not give access to all necessary knowledge. Six new names are presented Gymnodinium campbelli for the
homonymous name Gymnodinium translucens Campbell 1973, Gymnodinium antarcticum for the homonymous name
Gymnodinium frigidum Balech 1965, Gymnodinium manchuriensis for the homonymous name Gymnodinium autumnale
Skvortsov 1968, Gymnodinium christenum for the homonymous name Gymnodinium irregulare Christen 1959, Gymnodinium
conkufferi for the homonymous name Gymnodinium irregulare Conrad & Kufferath 1954 and Gymnodinium chinensis for the
homonymous name Gymnodinium frigidum Skvortsov 1968.