Synonyms :
Gonyaulax (Protogonyaulax)
tamarensis
Gonyaulax excavata
Morphological Characteristics
:
The organism may occur as single
cells or in pairs. Can be distinguished from other Alexandrium species
by its unique structure of plates and the distinct flattened posterior
end. The first apical plate carries a ventral pore.
The organism produces colourless, mucoid cysts, roughly ellipsoidal (35-40 mm long) in shape with rounded ends (see plates).
Size of Specimen :
22-30 mm (L), 25-36 mm (W)
Distribution :
The organism often occurs in the
waters of Japan, Phillippines, the coast of N. America and Australia. In
South China Sea, the species had been found in water samples of the eastern
waters of Hong Kong, Dapeng Bay, Daya Bay and the N. coast of Guangdong
Province, China. No red tide of this species has been recorded in the South
China Sea.
Major Limiting Factors :
NH4-N, temperature (18-25°C),
medium light illumination (2500-3000 lux) and high salinity (28-32%o).
Toxicity :
Severe PSP in Japan, USA and Europe.
