NAME Archaeomarasmius
AGE    AGE span:  mya
K&J CLASSIFICATION (2000) Basidiomycetes, Agaricales.
FIGURE(S)
FIGURE REFERENCE
SPECIES, AUTHORITY Archaeomarasmius Hibbett, Grimaldi & Donoghue 1997a, p. 982.
LOCATION
ORIG DESCRIPTION* ORIGINAL DIAGNOSIS: [combined description] Basidiomata medium-dark brown. Pileus 3.2 mm (AMNH NJ-90Y) to 6.0 mm (AMNY NJ-90Z) in diameter, circular, plano-convex, thin-fleshed (<1 mm), radially sulcate (Figs. 1-3); margin incurved; surface glabrous to minutely textured; veil absent; context thin. Lamellae distant to subdistant (12), without lamellulae, less than 1 mm wide at the widest point, attached to stipe apex; noncollariate, nonanastomosed; edges entire. Stipe 2.2 x 0.5 mm, base broken, insertion central, cylindrical, smooth, exannulate.

Basidiospores [from preparation AMNH NJ-90Z] 6.5-8.3 x 4.0-5.2 µm (mean dimensions: 7.3 x 4.7 µm; N=4 spores and 4 spore casts in amber), broadly ellipsoid to ovoid, smooth or possibly minutely textured, with a distinct hilar appendage (Figs. 3, 4-7).

The generic name indicates a presumed relationship with the extant genus Marasmius; the specific epithet honors J.J. Leggett and colleagues, whose alertness resulted in the discovery of this ancient fungus.
COMMENTS*
PUBLICATION REFERENCE Hibbett DS, Grimaldi DA, Donoghue MJ. 1997. Fossil mushrooms from Miocene and Cretaceous ambers and the evolution of Homobasidiomycetes; American Journal of Botany, v. 84, p. 981-991.
K&J REMARKS Although Kalgutkar and Jansonius (2000) indicated the type specimen as being the more complete specimen represented by fig. 1 (and the line drawing of fig. 3), Hibbett et al. cited two individuals (fig. 1-7) as constituting the type. Although ICBN Art. 37.3 requires a single specimen to be cited as type, Art. 8.1 allows that, for small herbaceous and for most non-vascular plants, the type may consist of more than one individual that should be conserved together. Kalgutkar and Jansonius (2000) consider the requirements of Art. 37.3 as more precise, but Art. 8.1 suggests that the name of this taxon was validly published.

The illustrated spores (fig. 3) were prepared out of the piece of amber containing the smaller wedge-shaped fragment of AMNH NJ-90Z (figs. 2, 4-7); the scale bar for the spores equals 7 µm.
TYPE TYPE: Archaeomarasmius leggettii Hibbet, Grimaldi & Donoghue 1997a, p. 982, fig. 1, 3 (AMNH NJ-90Y).
ALL NAMES (Including synonyms) Archaeomarasmius;
SERIAL NUMBER 45
PUBLIC COMMENTS
 *For source, see Publication Reference.