Bibliographic Detail
Hansen, G. & Daugbjerg, N., 2009
Reference:
Hansen, G. & Daugbjerg, N. (2009). Symbiodinium natans sp. nov.: a "free-living" dinoflagellate from Tenerife (Northeast-Atlantic Ocean). Journal of Phycology 45: 251-265.
Abstract:
We examined a free-living Symbiodinium species
by light and electron microscopy and nuclearencoded
partial LSU rDNA sequence data. The
strain was isolated from a net plankton sample collected
in near-shore waters at Tenerife, the Canary
Islands. Comparing the thecal plate tabulation of
the free-living Symbiodinium to that of S. microadriaticum
Freud., it became clear that a few but significant
differences could be noted. The isolate
possessed two rather than three antapical plates,
six rather than seven to eight postcingular plates,
and finally four rather than five apical plates. The
electron microscopic study also revealed the presence
of an eyespot with brick-shaped contents in
the sulcal region and a narrow anterior plate with
small knob-like structures. Bayesian analysis
revealed the free-living Symbiodinium to be a member
of the earliest diverging clade A. However, it
did not group within subclade AI (=temperate A)
or any other subclades within clade A. Rather, it
occupied an isolated position, and this was also
supported by sequence divergence estimates. On
the basis of comparative analysis of the thecal
plate tabulation and the inferred phylogeny, we
propose that the Symbiodinium isolate from Tenerife
is a new species (viz. S. natans). To elucidate
further the species diversity of Symbiodinium, particularly
those inhabiting coral reefs, we suggest
combining morphological features of the thecal
plate pattern with gene sequence data. Indeed,
future examination of motile stages originating
from symbiont isolates will demonstrate if this
proves a feasible way to identify and characterize
additional species of Symbiodinium and thus match
ribotypes or clusters of ribotypes to species.
