Glotzia balkanensis LG Valle & D Stoianova, 2020

Valle, Laia Guardia & Stoianova, Desislava, 2020, First record of Harpellales, Orphellales (Kickxellomycotina) and Amoebidiales (Mesomycetozoea) from Bulgaria, including a new species of Glotzia, MycoKeys 67, pp. 55-80 : 55

Glotzia balkanensis LG Valle & D Stoianova sp. nov. Figs 3-10

Holotype.

Bulgaria, Sofia, Pasarel Village, Iskar River, 42.535885N, 23.508824E; 712 m a.s.l.; 19 Aug 2016; LG Valle and D Stoianova Leg; In the hindgut of Baetis melanonyx Pictet ( Baetidae , Ephemeroptera ); microscope slide BCB-BUL-2-2.

Paratypes.

Same locality and date as the holotype; microscope slide BUL-2-3, BCB-BUL-2-4. Bulgaria, Sofia capital city, Darvenishka River, Park Vartopo, 42.645710N, 23.364568E; 585 m a.s.l.; 23 Aug 2016; LG Valle and D Stoianova Leg; In the hindgut of Baetis melanonyx ( Baetidae , Ephemeroptera ); microscope slide BCB-BUL-12-3.

Etymology.

Balkanensis , from the Balkan Peninsula.

Description.

Thalli measuring up to 600 μm long. Basal cell broadly inflated (18-30 μm diam.) and often branched (Fig. 3 ), bearing a small discoid secreted holdfast at the base or laterally to the basal cell axis (Fig. 4 ). Dichotomous branching above the basal cell; distal branches bearing spores (Figs 2 , 8 ). Trichospores cylindrical, with a terminal refractive cap (not always visible), measuring 44-56 × 4.5-5.5 μm, with 3 appendages, one central long filiform appendage, coiled around two shorter (about 15-20 μm) and broader lateral appendages (Fig. 10 ). These appendages can be seen within the generative cell while still attached (Figs 7 , 8 arrowhead). Fertile branches bearing 3-4 generative cells, measuring 20-35 × 4-6 μm. Zygospores biconical, 48-60 × 7.5-9.5 μm, with a collar 5-10 (-16) × 4 μm, attached eccentrically and laterally (Type II) to a zygosporophore 20-30 μm long, arising from the conjugation tube in series of scalariform conjugations (Fig. 9 ). In the hindgut of Baetidae ( Ephemeroptera ) nymphs.

Notes.

The genus Glotzia has nine species (including that described here), all of them sharing the characteristic cylindrical trichospores with a slightly globose cap and the peculiar 3-appendage arrangement observed also in G. balkanensis . This new species mostly resembles the type species G. centroptili described by Gauthier (1936) in French pools and streams of Dauphiné province (south-eastern France) from Centroptilum luteolum nymphs ( Baetidae ). This French species was recently rediscovered in Catalonia (Spain) also within Centroptilum sp. nymphs ( Busquets et al. 2018). This second observation in Spain was important for providing new material to complete the original description, which was scant and had no photographs, only a drawing of a single specimen ( Gauthier 1936). The specimens from Bulgaria can be differentiated from G. centroptili by spore characteristics. Trichospores of the Bulgarian species are longer than those observed in France or Spain (40 × 4 μm according to Gauthier (1936); 35-43 × 4-6 μm according to Busquets et al. (2018), up to 56 μm in the specimens reported here). All the fertile branches observed had a maximum of four generative cells in G. balkanensis , while up to seven have been reported in G. centroptili . Zygospores of G. balkanensis are quite similar to those of G. centroptili in length, but they have significantly larger diameter in the French species, 15 μm diameter (according to Gauthier 1936), while only 7.5-9.5 μm (8.4 μm average) in G. balkanensis . Unfortunately, the specimens of Glotzia centroptili collected from Spain, had no zygospores to compare with the new species, only trichospores were observed and, thus, we do not have a broad perspective of the zygosporic variation in this species, because apparently, the description of the type species was based on just a few specimens ( Busquets et al. 2018). The presence of a collar on released zygospores was not described by Gauthier in G. centroptili . The species described here has a quite variable collar length, but in most zygospores, it is rather short (5-10 μm). Regarding thallial characteristics, both species are quite similar, but there are major differences in their fertile branches, generative cells and in the basal cell. The basal cell is much more swollen in the Bulgarian species, resembling (but not identical to) that of the Italian species Glotzia distorta LG Valle, Santam. & W Rossi which has different spore features ( Valle et al. 2014). Most species of Glotzia are associated with Baetidae ( Ephemeroptera ), except for one species recorded in a New Zealand Plecoptera nymph, Glotzia plecopterorum Lichtw. ( Williams and Lichtwardt 1990) and another species living within Dixidae ( Diptera ) larvae Glotzia incilis Strongman & MM White, ( Strongman and White 2008). Actually, Glotzia is one of the Harpellid genera with a wider host range. Glotzia centroptili was recorded from Centroptilum ( Baetidae ) in France and Spain and G. distorta from the related Procleon pennulatum (= Centroptilum pennulatum ) ( Valle et al. 2014). However, Glotzia balkanensis has been recorded from a different host, Baetis melanonyx , but in the same family Baetidae . In fact, this is the first record of a Harpellid fungus within this host species.

Figures

Figures 3 - 10. Glotzia balkanensis sp. nov. from Baetidae nymphs. 3 thallus overview, note the inflated and branched basal cell structures 4, 5 detail of various swollen basal cells 6 loose zygospore with a collar 7, 8 trichospores on fertile branches, see the appendages inside the generative cell (arrowheads) 9 Zygospore arising from a conjugation tube 10 loose trichospore with a central long filiform appendage and two smaller lateral appendages. Scale bars: 50 µm (3), 25 µm (4 - 10).

Figures 1, 2. Genistellospora homothallica and Simuliomyces microsporus from Simuliidae larvae. 1 Fertile branches of G. homothallica with terminal trichospores 2 fertile branches and trichospores of G. homothallica with an attached thallus of S. microsporus showing a trichospore (arrow) and conjugation tubes (arrowhead). Scale bars: 25 μm in all figures.