Freshwater Ascomycetes - Species Monograph

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Genus	Species	Author
Aniptodera	megaloascocarpa	Raja et Shearer
Class	Order	Family
Sordariomycetes	Halosphaeriales

MycoBank ID: 507446

Synonymy:

Description

Habit:

Ascomata scattered, partly immersed to superficial on submerged woody debris.

Ascomata:

Ascomata on wood 1060–1360 × 430-–530 µm, scattered, immersed, hyaline membranous; venter large, globose, 490–650 × 485–580 µm, with a long, central, hyaline neck protruding through the surface of the wood when venter immersed.

Peridium:

Peridium composed of 2–4 layers of hyaline angular cells; cells 10–15 × 2–3 µm, of textura epidermoidea in surface view.

Beak:

Neck 540–850 × 70–80 µm, cylindrical, periphysate.

Hamathecium:

Catenophyses sparse, hyaline, septate, consisting of elongated cells, slightly constricted at the septa, ca. 70–100 × 5–10 µm.

Ascus:

Asci 100–128 × 20–26 µm, (mean = 116 × 24 µm, n = 30), thin-walled, clavate, flattened at apex, tapering to a pointed pedicel, unitunicate, persistent, wall thickened at the apex, ascus apex Melzer’s negative (MEZ neg), staining blue in aqueous nigrosin, cytoplasm retracted below the ascus apex; empty asci show an apical pore where the ascospores have been discharged; containing eight irregularly arranged ascospores.

Ascospore:

Ascospores 20-–26 × 9–11 µm (mean = 23 × 10 µm, n = 60), 1-septate, broadly ellipsoidal, thin-walled, with single large guttule in each cell, surrounded by an irregular gelatinous sheath ca. 2–5 µm wide at the ascospore apex; sheath staining in aqueous nigrosin, hyaline when young becoming pale brown to dark brown with age; septum becoming thicker and pigmented brown in older ascospores.

Sheath:

Gelatinous ca. 2–5 µm wide at the ascospore apex, staining with aqueous nigrosin.

Appendage:

Not observed.

Culture:

Anamorph:

Other info

Type & Location:

USA. FLORIDA: Ocala National Forest, Little Lake Kerr, 29°20_57_N, 81°43_49_W, water 21 C, pH 7, on submerged decorticated woody debris, 2 Feb 2006, HAR and JLC, F91-1. (ILL 40109).

Other Specimens:

Substratum:

Submerged woody debris.

Habitat:

Lentic.

Distribution:

USA (FL)

Pertinent Literature:

Raja, H. and C.A. Shearer. 2008.

Comments:

Aniptodera megaloascocarpa fits well within the concept of the genus with respect to ascomal, ascus and ascospore morphology . Aniptodera megaloascocarpa differs distinctly from other species in the genus because it has the largest ascomata (1060–1360 × 430–530 µm). In addition ascospores are surrounded by an irregular mucilaginous sheath. The mucilaginous sheath however cannot be seen when the ascospores are fixed in glycerin or lactic acid. Older ascospores of A. megaloascocarpa are pale brown and the septum is darkened ; these characters are not observed in other species of Aniptodera (Shearer 1989, Volkmann-Kohlmeyer and Kohlmeyer 1994, Hyde et al 1999). Aniptodera megaloascocarpa is similar to Phaeonectriella lignicola R.A. Eaton & E.B.G. Jones (Eaton and Jones 1970), which is characterized by having hyaline to pale brown globose ascomata with a long periphysate neck, clavate asci and hyaline ascospores with germ pores that become gray to brown at maturity. Aniptodera megaloascocarpa however differs from P. lignicola in having a larger ascoma and in ascospore morphology. Ascospores of P. lignicola possess a germ pore at each end, a feature not seen in ascospores of A. megaloascocarpa. In addition Hyde et al (1999) reported polar appendages in P. lignicola from specimens collected in Mauritius but ascospores of A. megaloascocarpa do not have apical appendages.

Additional Pictures

Asci separated from ascogenous hyphae.
Ascospore sheath stained in aqueous nigrosin.
Unstained asci.
Ascomata with branched neck.
Darkened ascospores.

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