Protozoa Guide review

RAPHIDOMONADIDA

order / RAPHIDOMONADIDA

Description

HEYWOOD & LEEDALE , 1983 by PETER HEYWOOD and GORDON F. LEEDALE Raphidomonads are biflagellated motile or palmelloid unicells lacking cell walls. Cells are ovoid to almost spherical , occasionally pyriform , occasionally lanceolate . They are often flattened dorsoventrally with a furrow on th e ventral surface . Chloroplasts are few (5) to many in number and contain chlorophylls a and c. An extensive Golgi apparatus often forms a ring over the anterior surface of the nucleus . Some species contain extrusomes (trichocysts or mucocysts). Interp hase nuclei and mitotic chromosomes are comparatively large . Meiosis and fertilization have not been described . Cysts are known for some genera. No fossils have been reported . Freshwater genera ( Gonyostomum, Merotricha, and Vacuo/aria) and marine genera ( Chattonella , Fibrocapsa, Heterosigma, and 0/isthodiscus) are recognized . Raphidomon ads may be locally abundant , giving rise to blooms . The order Raphidomonadida was often termed the Chloromonadophyceae (or some variant of this name) in algal literature; in classifications of the Protozoa the group was usually the Chloromonadida . These names were inappropriate , since the genus Chloromonas is not included within the class or order. We proposed (Heywood and Leedale, 1985) that the

Type species

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Raw text

HEYWOOD & LEEDALE , 1983
by
PETER HEYWOOD and GORDON F. LEEDALE
Raphidomonads are biflagellated motile or
palmelloid unicells lacking cell walls. Cells are
ovoid to almost spherical , occasionally
pyriform , occasionally lanceolate . They are
often flattened dorsoventrally with a furrow on
th e ventral surface . Chloroplasts are few (5) to
many in number and contain chlorophylls a and
c. An extensive Golgi apparatus often forms a
ring over the anterior surface of the nucleus .
Some species contain extrusomes (trichocysts
or mucocysts). Interp hase nuclei and mitotic
chromosomes are comparatively large . Meiosis
and fertilization have not been described . Cysts
are known for some genera. No fossils have been
reported .
Freshwater genera ( Gonyostomum, Merotricha,
and Vacuo/aria) and marine genera ( Chattonella ,
Fibrocapsa, Heterosigma, and 0/isthodiscus) are
recognized . Raphidomon ads may be locally
abundant , giving rise to blooms . The order
Raphidomonadida was often termed the
Chloromonadophyceae (or some variant of this
name) in algal literature; in classifications of
the Protozoa the group was usually the
Chloromonadida . These names were
inappropriate , since the genus Chloromonas is
not included within the class or order. We
proposed (Heywood and Leedale, 1985) that the