Ilytheomyces uncinatus W. Rossi & M. Leonardi, 2022

Buyck, Bart, Eyssartier, Guillaume, Armada, François, Corrales, Adriana, Hembrom, Manoj Emanuel, Rossi, Walter, Bellanger, Jean-Michel, Das, Kanad, Dima, Bálint & Ghosh, Aniket, 2022, Fungal biodiversity profiles 111 - 120, Cryptogamie, Mycologie 20 (2), pp. 23-61 : 25-26

111. Ilytheomyces uncinatus W. Rossi & M. Leonardi , sp. nov.

( Fig. 1 )

DIAGNOSIS. — Differs from all fifteen previously described species in the same genus for the shape of the hooked pre-apical outgrowth.

HOLOTYPE. — Nigeria. Ibadan, 13-24.VI.1977, leg. J. C. Deeming, on the sternites of Zeros fractivirgatus (Lamb) ( Diptera , Ephydridae ), holo-, FI ( WR2357 ).

INDEX FUNGORUM. — IF559552.

ETYMOLOGY. — From Latin: hooked, because of the shape of the perithecial outgrowth.

DESCRIPTION

Receptacle

Basal cell small, hyaline, irregularly shaped, prominent below the base of the appendage, lying side by side with the suprabasal cell, which is somewhat longer and almost wholly opaque.

Appendage

Relatively short, consisting of a linear series of 7-8 small, blackened cells, the second of which gives rise from its upper, inner angle to a very small, almost hyaline cell bearing distally two large, paired, elongate, brownish antheridia; the third cell bears a short, ramified branch with a few branchlets variably curved and opaque on the inner side; the other cells of the axis producing externally single short branches with recurved and hyaline extremities, which are disorganized in older specimens.

Perithecium

Stalk cell almost wholly opaque, slightly broader than long, narrower below. The basal cell region distinctly longer than the stalk cell, hyaline, except for a small, dark patch at the base of the secondary stalk cell. Perithecium grayish brown, asymmetrical, with the ventral margin distinctly convex and the dorsal almost straight; the tip very broad, rather abruptly distinguished on the ventral side, which is straight or concave, while the dorsal is slightly convex; the apex rounded and hyaline, subtended by a short, dark, suberect outgrowth ending in a small, paler hook.

Measurements

Length from foot to perithecial apex 110-125 µm; length from foot to tip of perithecial outgrowth 120-140 µm; appendage 50-60 µm; perithecium 55-65 × 23-30 µm.

NOTES

The genus Ilytheomyces includes to date 15 species, 11 of which were described from central and south America, 2 from Cameroon, and 2 from Malaysia ( Thaxter 1917, 1918, 1931). All the host insects were reported as unidentified species of Ilythea ( Diptera , Ephydridae ). It must be pointed out that the latter genus has been split and some species have been transferred to the genus Zeros Cresson. The only finding of Ilytheomyces published in the 90 years following Thaxter’s work consists in 4 species reported from Bolivia on Zeros fenestralis (Cresson) (synonym of Ilythea fenestralis Cresson ) ( Rossi 1998).

The new species is easily distinguishable from the other 15 species for the presence and shape of the hooked preapical outgrowth. The only two species previously reported from Africa are I. kamerunensis Thaxt. and I. falcatus Thaxt. , both described from Cameroon. The first is further distinguished for the “monstrously developed basal cell region” and the very long outgrowth, the latter for its “strongly incurved” thallus and the absence of the preapical outgrowth (words in quotes are the same utilized by Thaxter 1931).

Figures

FIG. 1. — Ilytheomyces uncinatus W. Rossi & M. Leonardi, sp. nov. from the type slide. Scale bar: 50 µm.