Australian Biological Resources Study

Australian Faunal Directory


Regional Maps

Phylum HAPLOSPORIDIA Caullery & Mesnil, 1899

Compiler and date details

November 2014 - Checked by Peter O’Donoghue, The University of Queensland

July 2010 - Data provided by O’Donoghue, entered in AFD by ABRS


Haplosporidia are characterised by the formation of unicellular spores (without polar capsules or polar filaments) that contain a single sporoplasm and several dense organelles (known as haplosporosomes). Spores have an orifice covered by an operculum or occluded by a lingua plug. The spores are covered with filamentous ornaments that sometimes appear as tails. They occur as parasites of invertebrate hosts in which uninucleate cells undergo modified schizogony to give rise to multinucleate plasmodia which develop into sporonts and eventually differentiate into spores. Most are histozoic or coelozoic parasites of aquatic molluscs, annelids, crustaceans and helminths. Several species cause significant diseases and mortality in oysters around the world.

Haplosporidian and paramyxean parasites have recently been grouped together on the basis of their molecular phylogenetic similarities in the Phylum Ascetospora Sprague, 1979, emend. Cavalier-Smith, 2009, placed near the base of the Cercozoa Cavalier-Smith, 1998, emend. Adl et al., 2005 (cf. Adl et al. 2012).



Unicellular protistan parasites, form unicellular spores without polar capsules or filaments.


History of changes

Note that this list may be incomplete for dates prior to September 2013.
Published As part of group Action Date Action Type Compiler(s)
09-Feb-2015 OPISTHOKONTA Cavalier-Smith, 1987 09-Feb-2015 MOVED
20-Nov-2014 HAPLOSPORIDIA Caullery & Mesnil, 1899 18-Nov-2014 MODIFIED
26-Jul-2012 26-Jul-2012 MODIFIED
26-Jul-2012 14-Mar-2012 MODIFIED
05-Jul-2011 ADDED