1. Introduction to unarmoured dinoflagellates
IOC Certificate of Proficiency in Identification
of Harmful Marine Microalgae
University of Copenhagen
6-19 August 2017
Introduction to
unarmoured dinoflagellates
Jacob Larsen
IOC Science and Communication Centre on Harmful Algae, Copenhagen, Denmark –

2. armoured or thecate
> 2000 species
most species (about 1700) occur in marine habitats
are unarmoured (naked), e.g. Amphidinium, Cochlodinium, Gymnodinium, Gyrodinium, Karenia; most species can be identified only in live samples
armoured species, e.g. Prorocentrum, Dinophysis, Protoperidinium, Alexand-rium, Gonyaulax, a.o. can be identified in preserved samples
The terms armoured/thecate vs. unarmoured/naked are descriptive terms, and do not carry any taxonomic meaning
unarmoured or ‘naked’

3. Gymnodiniales Lemmermann 1910
Bibliographic ghosts
Can never be identified on basis of their original description/illustration
Disregard such names and describe new species
Synonymize them with known, well-described species
Give them an identity through emended descriptions

4. Classic genera

5. Gymnodiniales 1. counterclockwise horseshoeshaped apical groove
Gymnodinium nolleri
Gymnodinium catenatum
Gymnodinium fuscum
Gymnodinium palustre
Gymnodinium cfr placidum
Gymnodinium aureolum (USA)
Gymnodinium aureolum (Denmark)
Gymnodinium chlorophorum
Gymnodinium impudicum
Karenia brevis
Karenia mikimotoi (Denmark)
Karenia mikimotoi (Japan)
Karlodinium micrum
Akashiwo sanguinea (USA)
Akashiwo sanguinea (Canada)
100 66 93
[Gyrodinium aureolum]
[Gymnodinium mikimotoi]
[Gymnodinium breve]
[Gyrodinium impudicum]
[Gymnodinium sanguineum]
[Gymnodinium galatheanumi]
2. nuclear chambers
3. nuclear fibrous connective
1. straight apical groove
2. major caretonoid pigments fucoxanthin and
fucoxanthin derivatives
1. amphiesmal plugs ventral pore
1. apical groove clockwise and loop-shaped
1. counterclockwise horseshoeshaped
apical groove
From Daugbjerg et al. 2000

6. Gymnodiniales Lemmermann 1910
Practical identification
Size and shape
Position of structure of girdle and sulcus (displacement, overhang)
Apical groove (often difficult to observe and not always visible in LM)
Surface striations
Presence/absence of chloroplasts, shape of chloroplasts, ± pyrenoid
Other organelles, nucleus and its position in the cell, ± nematocysts, ± ocelli, ± peduncle
LIVE MATERIAL USUALLY NEEDED, FOR CRITICAL ID
SEM AND/OR MOLECULAR DATA ARE NEEDED IN SOME CASES

7. Amphidinium carterae 12-18 µm long
one widely branched chloro- plast with a central pyronoid

8. Akashiwo Hansen et Moestrup 2000
SCCAP K-1107, photos Gert Hansen
apical groove running clockwise around the apex of the cell
nuclear envelope chambers and fibrous connective absent
peridinin is the major carotenoid pigment

9. Gymnodinium catenatum

10. Karenia Hansen et Moestrup 2000
with >10 described species
apical groove straight
major carotenoid pigments are fucoxanthin or fucoxanthin derivatives
nucleus without envelope chambers or capsule
Type species: K. brevis (Davis) Hansen et Moestrup

11. Genus Karenia
From Brand et al. 2012

12. Karlodinium veneficum
Cell length 8-18 µm
Girdle displacement 23-32%
Chloroplasts 2-4
Apical groove straight
Ventral pore present
Nucleus round, in left lobe of hypocone or central
Toxic

13. Karlodinium veneficum ~ armiger
Karlodinium armiger
From Bergholtz et al. 2005

14. Karlodinium veneficum
Karlodinium armiger
Which species are toxic, check
Karlodinium veneficum
20 µm
From de Salas et al. 2008

15. From Lim et al. 2014

16. Cochlodinium polykrikoides