Corethromyces gibbosus W. Rossi & Santam., 2020

Rossi, Walter, Das, Kanad, Hembrom, Manoj Emanuel, Santamaria, Sergi, Parihar, Arvind, Ghosh, Aniket, Henkel, Terry W., Hofstetter, Valerie & Randrianjohany, Émile, 2020, Fungal Biodiversity Profiles 91 - 100, Cryptogamie, Mycologie 20 (4), pp. 69-107 : 71-73

91. Corethromyces gibbosus W. Rossi & Santam. , sp. nov.

( Fig. 1 )

Relatively small species lacking any blackening and any outgrowth from the receptacle; perithecium small and asymmetrical, with a distinct hump on the ventral side; appendage consisting of a linear series of five gradually smaller cells bearing antheridial branches on the inner side.

HOLOTYPE. — Ecuador. Prov. Cotopaxi, Canton Sigchos, San Francisco de Las Pampas, 13. VI.2009, C. Tapia, on elytra of Dissochaetus curtus Portevin ( Coleoptera , Leiodidae ) (FI[FI WR 3417]).

MYCOBANK. — MB 832702.

ETYMOLOGY. — From Latin: humpbacked, referring to the “hump” on the anterior side of the perithecium.

ADDITIONAL EXAMINED MATERIAL. — Same data as the holotype, at the elytral tips of D. curtus , slide WR 3393. Ecuador. Prov. Zamora-Chinchipe, Estación Científica San Francisco, 3°58’19”S, 79°04’44.06”W, about 1900 m, 10-14.VIII.2014, M. Bernardi, W. Rossi & J. Torres, on abdominal tip of Dissochaetus curtus (para-, FI[FI WR3917]).

DESCRIPTION

Thallus slightly to distinctly bent posteriorly. Perithecium amber-yellow; the rest of the fungus paler to almost hyaline. Including basal cells relatively stocky, about twice as long as broad, distinctly asymmetrical, with the posterior margin almost straight, while the anterior one is very convex, and sometimes forming a distinct “hump” at the junction with the conical tip; the apex is rounded and undifferentiated. Length from foot to perithecial apex 117-163 µm. Perithecium (including basal cells): 61-79 × 30-36 µm. Longest appendage up to 130 µm. Receptacle gradually broadening from below upwards. Cell I irregularly trapezoidal, from slightly to 3× longer than maximum width. Cell II much larger than the former, 2-3× longer than broad, separated from cell III by a very oblique septum, while the septum dividing it from cell VI is shorter and less oblique. Cell III about 1.5× longer than broad, with the upper, outer angle distinctly bulging outwards. Main axis of the appendage consisting of five cells obliquely superposed and gradually smaller, each giving rise from the inner upper side to one or more antheridial branches; the latter consisting of a single series of cells separated by oblique septa, which are converted directed into simple antheridia that in older specimens are replaced by short branchlets. Cell VI shorter and broader than cell III. Cell VII relatively large, clearly bulging externally on the anterior side.

NOTES

The species of Corethromyces accepted to date are 89. However, this figure is provisional because the genus limits are not well-defined, notwithstanding the rearrangement carried out by Tavares (1985). Most of these 89 species occur on rove beetles ( Coleoptera , Staphylinidae ) and six only are found on hosts of other insect families. Three of the latter fungi were described on Leiodidae , the same family of the host of Corethromyces gibbosus W. Rossi & Santam. , sp. nov. These are C. bernardii Haelew. & W. Rossi , C. bicolor Thaxt. , and C. henrotii Balazuc , all of which are not only very different from the new species, but differ greatly also between them. ( Haelewaters & Rossi 2015; Rossi & Máca 2006; Weir & Huges 2002).

92. Corethromyces marshallii W. Rossi & Santam. , sp. nov.

( Fig. 2 )

Thallus lacking any blackening and any outgrowth from the receptacle; cells II, III, and VI hyaline and elongate; perithecium russet, subsymmetrical, pear-shaped.

HOLOTYPE. — Ecuador. Prov. Napo / Pichincha, Quito-Baeza pass, 4000 m, 4-8.XI.1999, S. A. Marshall, on sternites of Poecilantrops stellans Kits & Marshall ( Diptera , Sphaeroceridae ) (FI[FI WR3521]).

ADDITIONAL EXAMINED MATERIAL. — Same data as the holotype (para-, FI[WR3530a, WR3530b, WR3531]).

MYCOBANK. — MB832704.

ETYMOLOGY. — Named after the entomologist Stephen A. Marshall ( Canada), who collected and kindly sent us the insects bearing the new species.

DESCRIPTION

Perithecial venter russet; the rest of the thallus is almost hyaline or very faintly tinged with yellowish gray. Receptacle consisting of three superimposed cells separated by well defined constrictions, of which the basal (cell I) small and strongly bent; the suprabasal (cell II) much larger, subcylindrical, variably elongate, up to four times longer than broad; the stalk cell of the appendage (cell III) elongate, slightly narrower and subequal in length or slightly longer than cell

II. Appendage consisting of a large lower cell slightly longer than broad, followed by a linear series of 3-4 much smaller cells, each bearing on both sides short and hyaline branchlets variably branched; in fully mature thalli these branchlets form a rather unclear crest-like series usually exceeding in length the perithecial apex. Stalk cell of the perithecium (cell VI) distinctly shorter and narrower than cell III, usually directed obliquely outwards. The cells above distinguished by an abrupt constriction, relatively large and prominent, forming together a barrel-shaped structure usually longer than the maximum width. Perithecium pear-shaped, with the lower half symmetrically inflated, while the upper, subconical portion tapers gradually to a slightly asymmetrical, blunt apex. Length from foot to perithecial apex 150-295 µm; maximum length from foot to tip of appendages 375 µm; perithecium 53-100 × 23-47. The larger thalli were those growing on the sternites while the smaller ones were observed on the upper surface of the wings (and these latter never exceeding 175 µm from foot to perithecial apex).

NOTES

Corethromyces marshallii W. Rossi & Santam. , sp. nov., is the first species in the genus Corethromyces to be found on a fly: as mentioned above, most of the species in this genus are found on Staphylinidae . Poecilantrops stellans is a brachypterous fly living in the moss at high altitudes in the Equadorian Andes.

The Laboulbeniales reaching the altitude of 4000 m are very few, the record being held by Laboulbenia montana W. Rossi & M. Leonardi with 4605 m a.s.l. ( Das et al. 2018).

Figures

FIG. 1. — Corethromyces gibbosus W. Rossi & Santam., sp. nov.: A, B, two thalli from the type slide. Scale bars: 50 µm.

FIG. 2. — Corethromyces marshallii W. Rossi & Santam., sp. nov.: A, B, two thalli from the type slide; C, short thallus from the wing of the host insect, paratype WR3531. Scale bars: 50 µm.