Laboulbeniomycetes (Fungi, Ascomycota) of Denmark Author Santamaria, Sergi Unitat de Botànica, Departament de Biologia Animal, de Biologia Vegetal i d’Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès (Barcelona), Spain. sergi.santamaria@uab.cat Author Pedersen, Jan Natural History Museum of Denmark (Zoological Museum), University of Copenhagen, Universitetsparken 15, 2100 København Ø, Denmark. japedersen@snm.ku.dk text European Journal of Taxonomy 2021 2021-11-26 781 1 425 http://dx.doi.org/10.5852/ejt.2021.781.1583 journal article 10.5852/ejt.2021.781.1583 2118-9773 5828924 Monoicomyces validus Santam. sp. nov. MB#840609 Fig. 91 Diagnosis Similar to M. homalotae Thaxt. , but differing by the dark and constricted cell VI, and by the very stout, rounded, conspicuously convex antheridia, which are 1.5 times as long as broad (not considering the very short secondary appendages), each with four phialides. Etymology The species epithet means “stout”, because of the stocky antheridia. Type material Holotype DENMARK – Fyn (F) • Sprogø ; 55°20.012′ N , 10°58.263′ E ; PG23; on Atheta vestita (Gravenhorst, 1806) (Col. Staphylinidae Aleocharinae ); 7 Sep. 2013 ; JP 214 ; JP det.; ZMUC C-F-122693 . Paratypes DENMARK – Lolland, Falster, Møn (LFM) • Gedser Odde ; 54°33.687′ N , 11°57.806′ E ; PF95; on Aleochara grisea Kraatz, 1856 (Col. Staphylinidae Aleocharinae ); 21 Apr. 2019 ; JP 1429 ; JP det.; ZMUC C-F-123976 • ibid.; on A. vestita ; ZMUC C-F-123974 , C-F-123975 . – Nordvestjylland (NWJ) • Syd for Stårup ; 56°34.792′ N , 9°5.958′ E ; NH07; on A. vestita ; 6 Feb. 2015 ; JP 222 ; JP det.; ZMUC C-F-122703 . – Nordvestsjaelland (NWZ) • Dybesø ved Rørvig ; 55°58.117′ N , 11°45.004′ E ; PH70; on A. vestita ; 17 May 2019 ; JP 1465 ; JP det.; ZMUC C-F-124045 • Kongstrup Klint på Røsnaes ; 55°43.730′ N , 10°58.299′ E ; PG27; on Geostiba circellaris (Gravenhorst, 1806) (Col. Staphylinidae Aleocharinae ); 20–26 Sep. 2014 ; JP 236 ; JP det.; ZMUC C-F-122716 • Stold Skydeterraen ; 55°45.124′ N , 11°17.634′ E ; PG48; on A. vestita ; 25 May 2014 ; JP 378 ; JP det.; ZMUC C-F-122861 . Description Thallus amber coloured, with a blackened foot and outer margin of primary appendage. Basal cell of receptacle (I) obconical, often geniculate, about 1.5 times as long as broad, almost entirely dark. Suprabasal cell of receptacle (II) small, triangular to trapezoidal, broader than long. Cell III cylindrical, darkened outwards, supporting the primary appendage and, sometimes, an additional branch borne from the inner side. Usually, each thallus includes two secondary receptacles arising from cell II, including respective perithecia and antheridia. Primary appendage unbranched or, rarely, once ramified, darkened along its entire outer margin; short to very short, not exceeding in length the perithecial apex. Fig. 91. Monoicomyces validus Santam. sp. nov. A–B . Mature thalli. C–E . Antheridium at three focusing levels. C–D . Respectively in near and far focus. E . Middle focus in detail with the four tiers of cells (t1–4), and four phialides (an). F . Lower receptacle (I, II, and III) and primary appendage in detail above the primary septum (a). G . Ascospore. Scale bars: A–B = 50 µm; C–G = 20 µm. Photographs from slide ZMUC C-F-122693 (holotype). Antheridia consisting of four superposed tiers of paired cells, stout, stocky, rounded in outline, about 1.5 times as long as broad (not considering the secondary appendages). Cells of the four tiers shortening from below upwards. Each of the four cells of 2 nd and 3 rd tiers bear a phialide. The “sperm cavity” is sealed by four to several cells on both sides. Outer margins strongly convex ( Fig. 91C–E ). The 4 th tier bears 2–4 short, pale secondary appendages. Perithecial stalk cell (VI) 2–3 times as long as broad, narrower and darkened in its lower half. Perithecia ovoid, symmetrical, with a subacute, pointed apex. Perithecial basal cells (m, n, n’) and VII provided with “stigmata”. Ascospores with the basal cell (the longer) ending in a conical apex, and the apical cell (the shorter) bearing a rather pointed, but rounded tip ( Fig. 91G ). The spore wall expands into what will become the forthcoming foot of the thallus in an almost ellipsoidal outline. Length from foot to tip of perithecium 160–181 µm. Perithecium (including basal cells) 103–116 × 49– 52 µm. Antheridium (including pedicellar cell, without secondary appendages) 57–63 × 31–35 µm. Length of primary appendage (when undamaged) from primary septum above cell III 27–73 µm. Ascospores length (including expanded sheath at basal area) 34–35 µm. Thalli were found on various body parts of the hosts. The hosts were sifted from rotten seaweed on a stony sea shore, from rotten seaweed at the base of a coastal soft clay cliff, from semi-fresh flood debris on a coastal meadow, from moist rotten seaweed on a stony beach, from dry lichens and herbs on sunexposed sandy ground, and in pitfall traps on a sun-exposed, dry meadow. Remarks This species, which belongs to same group of M. homalotae (see additional explanations under M. brachiatus sp. nov. ), may be easily separated at first sight by the stockier antheridia.