Publication Date:
2018-12-11
Description:
One of the most common marine dinophytes is a
species known as Heterocapsa triquetra. When Stein
introduced the taxon Heterocapsa, he formally based
the type species H. triquetra on the basionym
Glenodinium triquetrum. The latter was described by
Ehrenberg and is most likely a species of
Kryptoperidinium. In addition to that currently
unresolved nomenclatural situation, the thecal plate
composition of H. triquetra sensu Stein (1883) was
controversial in the past. To clarify the debate, we
collected material and established the strain UTKG7
from the Baltic Sea off Kiel (Germany, the same
locality as Stein had studied), which was investigated
using light and electron microscopy, and whose
systematic position was inferred using molecular
phylogenetics. The small motile cells (18–26 µm in
length) had a biconical through fusiform shape and
typically were characterized by a short asymmetrically
shaped, horn-like protuberance at the antapex. A
large spherical nucleus was located in the episome,
whereas a single pyrenoid laid in the lower cingular
plane. The predominant plate pattern was identified
as apical pore complex (Po, cp?, X), 4', 2a, 6'', 6c,
5s, 5''', 2''''. The triradiate body scales were
254–306 nm in diameter, had 6 ridges radiating from
a central spine, 9 peripheral and 3 radiating spines,
and 12 peripheral bars as well as a central depression
in the basal plate. Our work provides a clarification
of morphological characters and a new, validly
published name for this important but yet formally
undescribed species of Heterocapsa: H. steinii sp. nov.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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