Stigmatomyces thoracochaetae Santamaria & Pedersen 2021, sp. nov.
Creators: name: Santamaria, Sergi
name: Pedersen, Jan
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Fungi
Ascomycota
Laboulbeniomycetes
Laboulbeniales
Laboulbeniaceae
Stigmatomyces
Stigmatomyces thoracochaetae

description: Stigmatomyces thoracochaetae Santam. sp. nov.
MB#840610
Fig. 62
Diagnosis
Similar to S. crassicollis, but differing by overall paler colour, brown wall thickenings below cell II and under perithecium, appendage axis with fewer rounded cells which are longer than broad, as well as by the distal area of appendage axis being curved backwards.
Etymology
The species epithet is derived from the name of the host insect (Thoracochaeta).
Type material
Holotype DENMARK – Nordvestsjaelland (NWZ) • On Thoracochaeta brachystoma (Stenhammer, 1855) (Diptera Sphaeroceridae); Bjerge Sydstrand; 55°34.046′ N, 11°9.459′ E; PG35; 24 Oct. 2018; JP 1207; V. Michelsen det.; ZMUC C-F-123733.
Description
Habitus slender. Thallus hyaline to pale yellowish, with slightly darker perithecial venter, and much darker basal cell of appendage. Basal cell of receptacle (I) obconical, about two times as long as broad, enlarged distally. Suprabasal cell of receptacle (II) almost cylindrical, longer than broad; bearing a brown wall thickening on the lower ventral side (Fig. 62A–B, D, H–J, arrows). Cell III outwards convex, about twice as long as broad, with its base at the same level as the II–VI septum.
Axis of appendage consisting of a dark, flattened basal cell above a constricted yet darker primary septum and five rounded, externally bulging, superimposed cells which are longer than broad, some of them slightly suffused with brown at their dorsal side. The lower four of these cells (including the basal) bearing one flask-shaped antheridium inwards, each with short, straight necks, and with squarish supporting cells. The two uppermost axial cells bear 1(–2) squarish cells supporting what seem to be sterile antheridia-like cells which are strongly backwards oriented (Fig. 62F, arrow).
Perithecial stalk cell (VI), secondary stalk cell (VII) and basal cells (m, n, n’) showing brown thickenings on the walls (Fig. 62J, *). Perithecial venter rounded, almost spherical. Neck long and narrow, gradually tapering until septum w 2 -w 3 which is marked by slight elevations, to the perithecial apex showing four lips, two of them ± protuberant (Fig. 62C). Preapical area slightly constricted.
Length from foot to tip of perithecium 220–303 µm. Perithecium (including basal cells) 151–170(–219) × 38–47 µm. Appendage length from primary septum to the apex 55–63(–80) µm. Ascospores length (including expanded sheath at basal area) 16–18 µm.
Thalli were found on the wings and sternites of the hosts. The hosts were sifted from moist, rotten seaweed on a sandy beach.
Remarks
This is the first species of a laboulbeniaceous fungus described on the genus Thoracochaeta. The species is particularly similar to S. crassicollis but may be separated from it by several characteristics like those mentioned in the diagnosis above, specially remarkable those related to the appendage arrangement.
description: Published as part of Santamaria, Sergi & Pedersen, Jan, 2021, Laboulbeniomycetes (Fungi, Ascomycota) of Denmark, pp. 1-425 in European Journal of Taxonomy 781 on pages 269-271, DOI: 10.5852/ejt.2021.781.1583, http://zenodo.org/record/5828924