Archaeospora J.B. Morton & Redecker
| Term | Description |
|---|---|
| Etymology: | Greek, “archaios” = ancient, referring to the ancient position of this genus in Glomales |
| Description: | All species form spores borne laterally or within the hypha subtending a “sporiferous saccule.” Although mode of formation is like that of species in Acaulosporaceae (hence a convergent trait), internal structure of spores is unique to this genus. |
| Type species: | Basionym: Acaulospora trappei R.N. Ames & Linderman |
Spore Ontogeny
Morphology indicated long ago that the two species in this genus, which were first classified as Acaulospora trappei and Entrophospora schenckii, did not belong in their respective genera because they did not share the two bilayered germinal walls that typified those genera. Where they belonged could not be deduced from morphology alone, however, because evolutionary polarity could not be determined from available evidence.
In other words, were these morphological differences more advance or more primitive? SSU data clearly placed Ar. trappei in a more primitive clade (Redecker et al., 2000). Sieverding and Oehl (2006) placed E. schenckii in its own genus, Intraspora, based exclusively on spore formation within the neck of a saccule, but these workers failed to recognize that spore position is a convergent trait, and therefore phylogenetically uninformative in defining monophyletic clades. Walker and Schüßler (2010) corrected this error, and placed the species in Archaeospora given its SSU relatedness to Ar. trappei.
Reference
- Morton, J. B. and D. Redecker. 2001. Two new families of Glomales, Archaeosporaceae and Paraglomaceae, with two new genera Archaeospora and Paraglomus, based on concordant molecular and morphological characters. Mycologia 93:181-195.
- Sieverding, W. and F. Oehl. 2006. Revision of Entrophospora and description of Kuklospora and Intraspora, two new genera in the arbuscular mycorrhizal Glomeromycetes. Journal of Applied Botany and Food Quality 80:69-81.