Freshwater Ascomycetes - Species Monograph

Click on the pictures below to view them at their full size.

Genus	Species	Author
Ophioceras	venezuelense	Shearer, J.L. Crane and Chen
Class	Order	Family
Sordariomycetes	Inc. sed	Magnaporthaceae

Synonymy:

Description

Habit:

Saprobic on submerged woody and herbaceous debris.

Ascomata:

Ascomata partially immersed to superficial, scattered, globose to subglobose, 730-890 x 745-868 µm, black, with long beak.

Peridium:

Ascomal wall thick, 64-159 µm wide, three-layered, even throughout except for thickening near base of beak; inner wall layer of compressed, elongate pseudoparenchymatic cells pigmented brown but lighter than middle layer, 13-21 µm wide; middle layer dark brown, comprised of pseudoparenchymatic cells occluded with amorphous brown material, 27-53 µm wide; outer layer of light brown, pseudoparenchymatic cells.

Beak:

Beak central, cylindrical, 250-800 x 122-137 µm, black, two-layered, 48 µm wide, inner layer dark, 29 µm wide, of elongated, compressed, brown cells, outer layer lighter, 18.6 µm wide, of pale brown, pseudoparenchymatic cells.

Hamathecium:

Hamathecium of long, hyaline, septate paraphyses longer than asci, broad at base, tapering toward apex.

Ascus:

Asci basal and peripheral, fusiform, falcate to sigmoidal, separating from hymenial layer, 148-180 (x = 167.7, s = 8.9, n = 30) x 11-18 (x = 14.3, s = 2.7, n = 30) µm, with or without a short stipe, stipe up to 11 µm long, with small thimble-shaped ascus apparatus staining blue in aqueous cotton blue, containing eight ascospores in a single fascicle.

Ascospore:

Ascospores filiform, falcate, more broadly rounded at one end than the other, 5 septate, occasionally 4 or 6 septate, hyaline, 130-158 (x = 138.1, s = 6.4, n = 30) x 2-4 (x = 3.0, s = 0.8, n = 30) µm; ascospores frequently released by deliquescence of basal half of ascus.

Sheath:

None observed.

Appendage:

None observed.

Culture:

Colonies on cornmeal agar immersed, hyaline, becoming pale gray, spreading with an even margin; on peptone, yeast extract, glucose agar, immersed and superficial, black, compact.

Anamorph:

None observed.

Other info

Type & Location:

HOLOTYPE. VENEZUELA. PORTUGUESA: Mountain stream two miles from La Estacion, on submerged decorticated wood, 16 Jan 1993, JLC, A-109-1, ILLS.

Other Specimens:

VENEZUELA. TACHIRA: Branch of Qda, La Pulida, on submerged wood, 26 Jan 1993, JLC, A-109-3; PORTUGUESA: Ca–o Maraca, on submerged woody debris, 17 Jan 1993, JLC, A-109-4; Mountain stream two miles from La Estacion, on submerged herbaceous debris, 16 Jan 1993, JLC, A-109-5, ILLS.

Substratum:

Submerged wood and herbaceous debris.

Habitat:

Streams.

Distribution:

Venezuela (Portuguesa, Tachira)

Pertinent Literature:

Shearer, C.A., J.L. Crane, and W. Chen. 1999. Freshwater Ascomycetes: Ophioceras species. Mycologia 91: 145-156.

Comments:

Additional Pictures

Ascospore
Immature ascus
Dehisced mature ascus
Ascus apical apparatus

Back