Neogregarinorida

Neogregarinorida
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	SAR
Clade:	Alveolata
Phylum:	Apicomplexa
Class:	Conoidasida
Subclass:	Gregarinasina
Order:	Neogregarinorida Grassé & Schrével 1953
Families
Caulleryellidae Gigaductidae Lipotrophidae Schizogregarinina Ophryocystidae Schizocystidae Syncystidae

The Neogregarinorida are an order of parasitic alveolates in the phylum Apicomplexa. ^[1] Species in this order infect insects and are usually found in the fat body, hemolymph, hypodermis, intestine or Malpighian tubules. The most common site of infection is the fat body: many species are pathogenic for their hosts.

The species in this order are predominantly intracellular parasites.

Taxonomy

Six families are in this order, with 13 genera. The type genus is Ophryocystis .

Two families (Ophryocystidae and Schizocystidae) belong to the suborder Schizogregarinina.

They appear to have evolved from the Eugregarinorida. ^[2] Merogony as part of the life cycle separates them from the Eugregarinorida and appears to have been derived as a secondary characteristic.

A phylogenetic analysis of the small subunit RNA suggests Ophryocystis may actually be a eugregarine rather than a neogregarine. ^[3]

General characteristics

• Merogony, gamogony and sporogony are present in all species
• They are septate with deutomerites, epimerites and protomerites
• A conoidal complex is present through a major portion of their life cycles
• A mucron is formed from eversion of the conoidal complex similar to the eugregarines
• Merogony occurs by budding from the meront cell surface as in the coccidia
• Gamonts join in head-to-head syzygy (the conoidal complexes face each other)

References

1. Jeon, Kwang W. (2006). International Review Of Cytology: A Survey of Cell Biology. Academic Press. ISBN   978-0-08-046350-6.
2. Leander BS (February 2008). "Marine gregarines: evolutionary prelude to the apicomplexan radiation?". Trends Parasitol. 24 (2): 60–7. doi:10.1016/j.pt.2007.11.005. PMID   18226585.
3. Leander BS, Harper JT, Keeling PJ (December 2003). "Molecular phylogeny and surface morphology of marine aseptate gregarines (Apicomplexa): Selenidium spp. and Lecudina spp" . J. Parasitol. 89 (6): 1191–205. doi:10.1645/GE-3155. PMID   14740910.