A CHECKLIST AND CLASSIFICATION OF LIVING DINOFLAGELLATES (DINOFLAGELLATA, ALVEOLATA)

66 GÓMEZ
laboratories. At present, sequences of many
species are lacking and the molecular phylogenies
did not resolve the relationships between
the higher ranks. The classical orders
(Peridiniales, Gymnodiniales, Prorocentrales)
appear to be polyphyletic in the SSU and LSU
rDNA phylogenies (Saldarriaga et al., 2004;
Moestrup & Daugbjerg, 2007), and even orders
such as Dinophysales (Gómez et al., 2012).
The earlier molecular phylogenies revealed
the apicomplexan parasites as the closer relatives
of dinoflagellates (Gajadhar et al., 1991).
The dinokaryon is a distinctive character of
the dinoflagellate core, while basal dinoflagellates
show intermediate morphological and
ultrastructural characters that make difficult to
establish a clear cut between the Dinokaryota
and Apicomplexa. A recent study suggested
that perkinsid parasites should be considered
as an independent phylum (Zhang et al., 2011).
The exclusion of Perkinsozoa, restricted to 10
species of 2 genera, has a little influence on
the total account of dinoflagellate species. Environmental
molecular surveys of SSU rRNA
genes revealed the existence of novel alveolate
sequences indicating two large and diverse
clades close to the Dinokaryota that were initially
named Marine Alveolate Groups I and II
(López-García et al., 2001). Subsequently, it
has been shown that these groups corresponded
to parasitic dinoflagellates previously placed
within the order Syndiniales based on several
morphologically characterized representatives
for which SSU rDNA sequences were available
(Skovgaard et al., 2005; Harada et al., 2007).
The phagotrophic free-living flagellate Oxyrrhis
(Saldarriaga et al., 2003) and the ellobiopsid
parasites (Silberman et al., 2004; Gómez et al.,
2009) constituted other morphologically characterized
clades of basal dinoflagellates.
This study provides a checklist of all the
described dinoflagellate species updated to
December 2011. When sequences are available,
the species were organized in agreement
between the clades observed in the phylogenetical
trees and classical ranks taxonomical
schemes (genera, family, order, etc.). This is
not a simple task because the topology of the
trees varied with the type of molecular marker,
the taxa sampling, sequence length, or methods
for the construction of the phylogenetical
trees. Any classification is unavoidably associated
with discrepancies among authors.
MATERIAL AND METHODS
This study is based on literature records
of dinoflagellates. The primary source was the
checklist by Gómez (2005) updated with the
taxonomical innovations, and numerous errors
have been corrected. The checklist was
completed with the freshwater species. Major
sources were Schiller (1931-1937), Bourrelly
(1970) and Popovský & Pfiester (1991), and for
parasitic dinoflagellates: Chatton (1920), Cachon
& Cachon (1987) and Shields (1994). The
checklist was completed and updated with the
recent literature.
The species names with their nomenclatural
authorities and the year of the description
were arranged alphabetically within the
genus. Genera were ordered alphabetically
within each family. The authorities of each genus
and species were spelled according to the
International Plant Names Index. These name
spellings were also used for the places of publication
of the suprageneric ranks (family, order
and class). The International Code of Zoological
Nomenclature (I.C.Z.N.) and the International
Code of Botanical Nomenclature (I.C.B.N.)
have been applied for basal dinoflagellates and
Dinokaryota, respectively. This explained slight
differences in some species names. For example,
the epithets dedicated to Édouard Chatton
were spelled ‘chattoni´ and ‘chattonii´ for basal
dinoflagellates and dinokaryotes, respectively.
It is often difficult to decide what species
should be considered valid. Gómez (2005) labeled
with an asterisk (*) the species of very
doubtful validity that were not considered for
species counting. These insufficiently known
taxa were mainly constituted by species with
too poor original descriptions, for example,
some unarmoured dinoflagellates described
from fixed material in the earlier literature with
excessively simple line drawings. These ‘literature
ghosts’ have been considered valid despite
they may correspond to species that were further
described with more detailed descriptions.
Several studies of freshwater species reported
a high number of new species (i.e., Schiller,
1955; Baumestier, 1957; Skvortzov, 1968).
These species are considered valid, although
they need to be re-investigated because they
may correspond to life stages of other known
species. Four species (Protoceratium, Oxytoxum
breve) that were described lacking any
illustration have been listed, although excluded
of the species counting. Species names
cited in the literature, although never formally
described, have been excluded. Despite the
species are invalid, several of these species
names have been cited and labeled as ‘nomen
nudum’ (nom. nud.). The aim is to alert of the
possible homonymy when describing a new
species using the same name. There are several
homonyms (i.e., Gymnodinium excavatum,
G. hyalinum, G. irregulare, G. oceanicum, etc.),
that need a specific study before to propose an