Stephanosphaera

Stephanosphaera
Stephanosphaera pluvialis
Scientific classification Edit this classification
Clade: Viridiplantae
Division: Chlorophyta
Class: Chlorophyceae
Order: Chlamydomonadales
Family: Haematococcaceae
Genus: Stephanosphaera
Cohn
Species:
S. pluvialis
Binomial name
Stephanosphaera pluvialis
Cohn

Stephanosphaera is a genus of green algae in the family Haematococcaceae, containing the single species Stephanosphaera pluvialis.[1] It forms colonies of flagellated cells. Although it was once placed in the family Volvocaceae,[2] it is not closely related to them; its sister is the unicellular genus Balticola.[3] The name comes from the Greek roots stephanos, meaning "crown", and sphaira, meaning "ball".[4]

Description

Stephanosphaera pluvialis forms colonies of four or eight cells, arranged in a ring and surrounded by a spherical matrix. Each cell is elongated, irregularly shaped with several protrusions that join the cells together. Cells contain several contractile vacuoles, a rounded stigma, and a single large parietal chloroplast with usually two pyrenoids. Cells have two flagella of equal length.[3][5]

Reproduction

Stephanosphaera pluvialis reproduces both asexually and sexually. Asexual reproduction occurs by autocolony formation: a cell divides until it becomes like a miniature version of the existing colony, and the new colony is released from the cell.[3] Sexual reproduction is done with gametes, which are isogamous.[3]

Distribution

Stephanosphaera pluvialis is found in freshwater habitats. It tends to occur in rainwater puddles on non-basic rocks, more rarely in lakes.[6] It is rare.[1]

References

  1. ^ a b Guiry, M.D.; Guiry, G.M. "Stephanosphaera". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2023-02-15.
  2. ^ Kofoid, C.A. (1899). "Plankton studies. III. On Platydorina, a new genus of the family Volvocidae, from the plankton of the Illinois River". Bulletin of the Illinois State Laboratory of Natural History. 5 (9): 419–440, pi. 38. doi:10.21900/j.inhs.v5.420.
  3. ^ a b c d Nakada, Takashi; Nozaki, Hisayoshi (2014). "Chapter 6. Flagellate Green Algae". In Wehr, John D.; Sheath, Robert G.; Kociolek, J. Patrick (eds.). Freshwater Algae of North America: Ecology and Classification (2 ed.). Elsevier Inc. ISBN 978-0-12-385876-4.
  4. ^ Shayler, Hannah; Siver, Peter A. (2004). "Stephanosphaera". Carolina Lucid Key to Freshwater Algae. Connecticut College. Retrieved 2024-11-28.
  5. ^ Bicudo, Carlos E. M.; Menezes, Mariângela (2006). Gêneros de Algas de Águas Continentais do Brasil: chave para identificação e descrições (2 ed.). RiMa Editora. p. 508. ISBN 857656064X.
  6. ^ Kaštovský, Jan (2008). "A report of Stephanosphaera pluvialis Cohn 1852 (Chlorophyta, Chlamydophyceae)". Fottea. 8 (2): 109–110. doi:10.5507/fot.2008.006.