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 Chaetarthriomyces crassiappendicatus Scheloske MB#327992 Fig. 22A–B Parasitologische Schriftenreihe 19: 97 ( Scheloske 1969 ; as C. crassappendicatus ) . – Type : [In?] “Auf den Elytren und nahe der Basis der Schenkel der Hinterbeine von Chaetarthria seminulum (Col. Hydrophilidae ). Die Wirte stammen von einer feuchten Wiese in Ufernähe des Hembach bei Schwand/ Nürnberg sowie aus dem flachen Wasser (zwischen Pflanzen) eines Weihers bei Dechsendorf/Erlangen, Deutschland . Holotypus Abb. 10”. [ Germany ] Diagnostic features Primary appendage consisting of 5–6 isodiametric cells culminated with a rounded uppermost cell; the intermediate cells separate 1–2 small and short antheridia at one or at opposite sides ( Fig. 22A , arrows). Perithecium showing a short neck and a ± bent, asymmetric, subacute apex. [Detailed descriptions: Majewski 1994b ; Santamaria 2003 ] Fig. 22. Chaetarthriomyces spp. A –B . C. crassiappendicatus Scheloske. Mature thalli with labelled antheridia (arrows). – C–D . C. spiralis Santam. Mature thalli. Scale bars: 50 µm. Photographs from slides ZMUC C-F-123215 (A–B), ZMUC C-F-123214 (C–D). Distribution and hosts On Chaetarthria (Col. Hydrophilidae ) from Germany ( type ), Poland ( Majewski 1972a ), Spain ( Santamaria 1989 ), United Kingdom (Weir 1996), Sweden ( Huggert 2010 ), and the Netherlands (Haelewaters et al. 2014). Collections examined from Denmark On Chaetarthria seminulum (Herbst, 1787) (Col. Hydrophilidae ) DENMARK – Nordvestsjaelland (NWZ) • Flyndersø ved Dybesø ; 55°58.151′ N , 11°45.621′ E ; PH60; 4 Nov. 2017 ; JP 722 ; JP det.; ZMUC C-F-123215 . Remarks First record from Denmark . The finding of this species in Denmark was expected by its presence in the neighbouring countries. The thalli of this fungus can easily be overlooked due to their small size.