Hydrophilomyces hamatus T.Majewski

Santamaria, Sergi & Pedersen, Jan, 2021, Laboulbeniomycetes (Fungi, Ascomycota) of Denmark, European Journal of Taxonomy 781, pp. 1-425 : 51-52

Hydrophilomyces hamatus T.Majewski

MB#315333

Fig. 7F–G

Acta Mycologica 10: 274 ( Majewski 1974). –

Type: “ On Cercyon bifenestratus Küst. (Col., Hydrophilidae ): Pomiechówek, Nowy Dwór Mazowiecki county, in mud on the left bank of the River Wkra , 13.6.1973 leg. T. Majewski ( TM. 1301 – holotype)”; KRAM. [ Poland]

Diagnostic features

Receptacle stout, consisting of up to 22 flattened cells. Buffer cells present ( Fig. 7F–G , bf). Perithecial neck bent. [Detailed description: Majewski 1994b]

Distribution and hosts

On Cercyon (Col. Hydrophilidae ) from Poland (type), United Kingdom ( Weir & Beakes 1993), Sierra Leone ( Rossi 1990), and maybe from Belgium ( De Kesel et al. 2020).

Collections examined from Denmark

On Cercyon littoralis (Gyllenhal, 1808) (Col. Hydrophilidae )

DENMARK – Lolland, Falster, Møn (LFM) • Tjørnebjerg ved Kramnitse ; 54°41.586′ N, 11°16.980′ E; PF46; 19 May 2019; JP 1463; JP det.; ZMUC C-F-124042 , C-F-124043 .

Remarks

First record from Denmark. According to Majewski (1974), Hydrophilomyces hamatus is distinguished from H. gracilis by the presence of buffer cells, by the strongly recurved neck of the perithecium (although only seen on overmature perithecia), and by the stout receptacle, with less cells. Hydrophilomyces hamatus grows on the ventral side of the thorax or between coxae and the base of legs, whereas H. gracilis grows on the elytral apices. Majewski (1994b) considers the possibility that both species might be “growth forms of the same species”.

These species may exist on the same host specimen and their position is not related to host sex as is the case for example with H. coneglianensis and its synonym H. elegans . For this reason we prefer to maintain both species separate.

Figures

Fig. 7. Hydrophilomyces spp., mature thalli. A–B. H. coneglianensis Speg. Thallus from female (A) and from male hosts (B). – C. H. digitatus F.Picard. – D–E. H. gracilis T.Majewski. – F–G. H. hamatus T.Majewski. Abbreviations: acc = accessory cell; bf = buffer cells. Scale bars: 50 µm. Photographs from slides ZMUC C-F-122709 (A), ZMUC C-F-124088 (B), ZMUC C-F-124274 (C), ZMUC C-F-124043 (D–F), and ZMUC C-F-124042 (G).