Spiropes croissantiformis Berm.-Cova & M. Piepenbr., 2024

Bermudez-Cova, Miguel A., Hofmann, Tina A., Yorou, Nourou S. & Piepenbring, Meike, 2024, Systematic revision of species of Atractilina and Spiropes hyperparasitic on Meliolales (Ascomycota) in the tropics, MycoKeys 103, pp. 167-213 : 167

Spiropes croissantiformis Berm.-Cova & M. Piepenbr. sp. nov.

Fig. 8

Holotype.

On Meliola cf. xylopiae on living leaves of Xylopia frutescens , Panama, Chiriquí Province, Cochea, Cochea River Trail, 8°32'37"N, 82°23'03"W, 181 m a.s.l., 26 February 2020, M.A. Bermúdez, A. Sanjur, A. Villarreal, MB110 (UCH).

Etymology.

Named after the shape of the conidia.

Description.

Colonies effuse, dark brown to black, with tightly packed hyphae that form erect, dark synnemata clearly visible under the stereomicroscope. Hyphae superficial, branched, septate, 1-2 µm wide, straw-coloured, smooth. Conidiophores tightly packed to form dark brown to blackish synnemata up to 400 µm high, spreading out at the apex, up to 80 µm diam. Individual hyphae mostly straight, cylindrical, 3-5 µm thick, with numerous small scars, brown, paler towards the apex, rough. Conidia straight or curved, mostly crescent-shaped, sometimes fusiform, mostly 3(-5)-septate, (14-)20-24(-33) × (3.5-)5-6.5 µm, with two golden brown middle cells and paler cells at each. As seen by SEM, the ornamentation of the spores is distinctly reticulated, with thin to thick networks and no ridges.

Known distribution.

On colonies of Meliola cf. xylopiae on living leaves of Xylopia frutescens ( Annonaceae ) in Panama.

Notes.

Spiropes xylopiae is a synnematous hyperparasitic species of Spiropes with the shortest synnemata (up to 400 µm), when compared to other synnematous species, such as S. melanoplaca with synnemata that can reach up to 1.5 mm and S. penicillium with synnemata up to 700 µm high. In addition to this, the new species has crescent-shaped conidia, a feature that is not present in any other known species of the genus.

Figures

Figure 8. Spiropes croissantiformis (MB 110) a synnemata (indicated by white arrows) growing on colonies of Meliola cf. xylopiae b synnema (indicated by a black arrow) c conidiophores with scars and young conidia, shown in optical section d conidia shown in optical section. The thickness of the wall is only shown for the first spore from the left e, f as seen by SEM e part of a conidiophore with scars f conidia. Scale bars: 160 μm (a); 400 μm (b); 5 μm (c, d); 5 μm (e); 10 μm (f).