Compsomyces Thaxt.

Santamaria, Sergi & Pedersen, Jan, 2021, Laboulbeniomycetes (Fungi, Ascomycota) of Denmark, European Journal of Taxonomy 781, pp. 1-425 : 41-42

Genus Compsomyces Thaxt.

MB#1200

Proceedings of the American Academy of Arts and Sciences 29: 96 ( Thaxter 1894). –

Type species: C. verticillatus (Thaxt.) Thaxt.

Moschomyces Thaxt., Proceedings of the American Academy of Arts and Sciences 29: 97 ( Thaxter 1894) [MB#3277]

Brief description

Monoecious. Cell II supporting secondary axes and appendages bearing simple sessile antheridia. Perithecia borne on the secondary axes; outer wall with 4–8 unequal cells in each vertical row. Asci with 4 or 8 ascospores.

Remarks

The genus consists of five or six species depending on whether C. macropoda is regarded as a separate species or is included among the synonyms of C. verticillatus ( Santamaria 2003) . No new species have been added after Thaxter (1931). Two in Europe, both in Denmark. This genus is remarkable because perithecia are borne on secondary instead of primary receptacle, and because there are species, like C. verticillatus (Thaxt.) Thaxt. which show 8-spored asci instead of the usual 4-spored asci, a character exclusively shared within the Laboulbeniales with the genus Euceratomyces ( Tavares 1985) . It seems quite logical to think that this genus needs a revision and probably needs to be subdivided. Some characteristics accepted as essential to segregate genera, such as the number of perithecial wall cells is here very different from one species to the other. Indeed, the number of cells in each vertical row of wall cells in perithecium varies from four in C. lestevae to 6–8 in C. verticillatus .

Key to the Danish species (partially following Santamaria 2003)

1. Perithecium with each vertical row of outer wall cells consisting of 6–8 subequal cells ( Fig. 5E , arrows). On Astenus (Col. Staphylinidae ) ......................................... C. verticillatus (Thaxt.) Thaxt.

– Perithecium with each vertical row of outer wall cells consisting of four unequal cells ( Fig. 5A , arrows). On Lesteva (Col. Staphylinidae )............................................................... C. lestevae Thaxt.

Figures

Fig. 5. Compsomyces spp. A–B. C. lestevae Thaxt. A. Mature thallus showing antheridium (an) and perithecial wall cells (arrows). B. Immature thallus showing antheridium (an). – C–E. C. verticillatus (Thaxt.) Thaxt. C–D. Mature thalli. E. Detail of perithecium labelling eight wall cells (arrows). Scale bars: A–D = 50 µm; E = 20 µm. Photographs from slides ZMUC C-F-122939 (A–B), and ZMUC C-F- 124184 (C–E).