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MORPHOLOGY AND LIFE CYCLE EVENTS IN PYROPHACUS STEINII (SCHILLER) WALL ET DALE (DINOPHYCEAE)
Author(s) -
Faust Maria A.
Publication year - 1998
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1046/j.1529-8817.1998.340173.x
Subject(s) - biology , anatomy , morphology (biology) , hyaline , cell division , dinophyceae , cingulum (brain) , botany , cell , paleontology , medicine , ecology , fractional anisotropy , phytoplankton , radiology , nutrient , magnetic resonance imaging , white matter , genetics
Cells of Pyrophacus steinii (Schiller) Wall et Dale are round and lens shaped and have an anteroposteriorly compressed theca. The epitheca has a truncated, conical horn and a hexagonally shaped apical pore plate with two arched slits positioned off center. The cingulum is equatorial, narrow, and deep. The hypotheca is flat. The sulcus is narrow, slightly curved, and recessed and does not reach the cell’s antapex. The plate formula in these specimens of P. steinii is Po, 8′, Oa, 13", 13C, 12"′, 3p, 3"", and 8S with a difference in the number of precingular (13") and postcingular (12"′) plates. No additional posterior intercalary plates were present (Oap). Pregametic stages of P. steinii were observed during cell division via binary fission, with formation of two cells and multiple division with formation of four and eight cells. These newly formed cells were pale in color and were enclosed in double‐layered hyaline membrane. Gametes with gymnodinoid morphology were observed within the parental cells. Planozygotes are large and round and enclosed in double‐layered hyaline membrane. Mature cell forms are brown with a microgranular cytoplasm, storage bodies, and a red accumulation body. The hypnozygote exhibits triple‐layered hyaline membrane, irregularly shaped and comparable with bulbous processes of Tuberculodinium vancampoae Rossigol resting cysts. Division within a hypnocyst of P. steinii involves shedding the parental theca and the development and emergence of two daughter cells with the size and morphology of pregametic cells.