Kainomyces isomali Thaxt.

MB#431753

Fig. 6A–F

Proceedings of the American Academy of Arts and Sciences 37: 44 (Thaxter 1901b). –

Type: “On Isomalus Conradti Fauvel. Derema, Usambara, East Africa. Berlin Museum, Nos. 847–848”; FH. [Tanzania]

Diagnostic features

Cells in the lower receptacle darkened basally but especially towards the dorsal margins; some of them divided by longitudinal septa. The pigmentation is a consequence of merged spots in a characteristic comb-like pattern (Fig. 6F). [Detailed descriptions: Thaxter 1908; Lee & Sugiyama 1984]

Distribution and hosts

Reported on Eleusis Laporte, 1835 and Isomalus Erichson, 1839 (which now is a synonym of Eleusis) (Col. Staphylinidae Osoriinae) from Tanzania (type), Burundi (Thaxter 1908), Cameroon, Philippines, Sumatra, Java, Borneo (Thaxter 1931), Zaire (Collart 1947), Taiwan (Sugiyama 1978a), and Bali Island (Lee & Sugiyama 1984). Also on Maseochara (Col. Staphylinidae Aleocharinae) from Sumatra (Thaxter 1931) but the host identification seems incorrect according to Frank (1982); Maseochara is a subgenus of Aleochara Gravenhorst, 1802.

Collections examined from Denmark

On Gyrohypnus angustatus Stephens, 1833 (Col. Staphylinidae Xantholininae)

DENMARK – Nordøstsjaelland (NEZ) • Brede; 55°47.650′ N, 12°29.951′ E; UB48; 30 Aug. 1876; Løvendal Dry0185; Schiødte det.; ZMUC C-F-124250 • København; 55°41.332′ N, 12°33.762′ E; UB47; 11 Apr. 1911; O. Jacobsen Dry0187; O. Jacobsen det.; ZMUC C-F-124252 • Malmmose; 55°48.134′ N, 12°26.364′ E; UB38; May 1899; N.P. JØrgensen DrY0186; N.P. Jørgensen det.; ZMUC C-F-124251. – Sydsjaelland (SZ) • Gammel Kalvehave; 54°59.745′ N, 12°8.232′ E; UA19; 25 Apr. 2019; JP 1452; JP det.; ZMUC C-F-124002.

Remarks

First European record. The presence of this fungus in European beetles of the genus Gyrohypnus Leach, 1819 was unexpected and defies any explanation. The single species of Laboulbeniales recorded hitherto on Gyrohypnus (as Xantholinus, Tavares 1985) was Peyritschiella infecta (Thaxt.) I.I.Tav. from USA (Thaxter 1894).

Kainomyces isomali, K. alutellae Thaxt. and K. hyalinus Terada are similar species. According to Rossi & Leonardi (2018), K. hyalinus should be synonymized with K. alutellae because the brown pigmentation in the receptacle is a variable characteristic, useless for distinguishing these taxa. Kainomyces isomali is separated by the vertical septa in receptacle, lacking in K. alutellae. Kainomyces rehmanii T.Majewski which occurs on Acrotrichis Motschulsky, 1848 (Col. Ptiliidae) is an isolated species, well-distinguished from other species.

The basal area of perithecia appears to be variably darkened. When observed in detail with the help of DIC optics, brown round spots or circles may be distinguished (Fig. 6D). These elements recall the “stigmata” also observed in species of the genus Monoicomyces, Rhachomyces and Stigmatomyces. Tavares (1985) stated that determination of the exact nature of antheridia in this species was not possible but suggested that they are the terminal cells in the rows of frequently divided cells above the perithecium. We agree with this statement because numerous flask-shaped, flattened, laterally directed antheridia may be found among the tiers of cells in the massive receptacle (Fig. 6E, an).