Pyrenula inspersa M.Z. Dou & Z.F. Jia, 2024

Dou, Mingzhu, Liu, Shengnan, Li, Jiechen, Aptroot, Andre & Jia, Zefeng, 2024, Three new Pyrenula species with 3 - septate ascospores with red or orange oil when over-mature (Ascomycota, Pyrenulales, Pyrenulaceae) from China, MycoKeys 102, pp. 107-125 : 107

1. Pyrenula inspersa M.Z. Dou & Z.F. Jia sp. nov.

Fig. 2

Diagnosis.

The new species can be distinguished from the most similar species Pyrenula thailandica Aptroot by the hamathecium densely inspersed with minute granules and colourless oil droplets.

Type.

China. Hainan Province: Changjiang County, Bawangling Nature Reserve, Yajia , 19°05′07′′N, 109°07′25′′E, alt. 444 m, on bark, 10 December 2017, X.H. Wu HN17058 (LCUF: holotype: HN17058; GenBank OR 578591 for ITS and OR578572 for LSU) .

Description.

Thallus corticolous, crustose, brown, surface dull, uneven, corticate with pseudocyphellae, UV-. Ascomata perithecioid, emergent, dispersed, aggregated occasionally when crowded, hemispherical, 1-1.5 mm diam., with crystals, KOH-. Ostioles apical. Hamathecium heavily inspersed with minute granules and colourless oil droplets (close-up in Suppl. material 2), IKI-. Ascospores 8 per ascus, irregularly biseriate, with gelatinous halo before becoming old, 3-septate, 28.5-50 × 10-20 μm; middle lumina diamond-shaped, end lumina triangular, with a thick layer of endospore in the spore tips; hyaline when young, brown when mature, over-mature ascospores with orange oil.

Chemistry.

Thallus K-, C-, KC-, UV-, hamathecium IKI-.

Ecology and distribution.

The new species is currently only known from the tropical regions of southern China on bark.

Etymology.

The specific epithet inspersa refers to the inspersed hamathecium.

Note.

This new species is similar to Pyrenula thailandica , P. bahiana and P. concastroma in having 3-septate ascospores with red or orange oil when over-mature. It differs from P. thailandica by an inspersed hamathecium and larger ascomata, which are in the latter species 0.6-1.1 mm wide ( Aptroot 2012; Aptroot et al. 2012, 2013; Ingle et al. 2018). This new species differs from P. bahiana by larger ascospores, which are in the latter species 26-33(-35) × 10-13(-15) μm ( Malme 1929; Aptroot 2012; Aptroot et al. 2013; Ingle et al. 2018). Pyrenula concastroma differs from the new species by the mostly aggregated ascomata with fused walls, but separate ostioles ( Aptroot 2012; Schumm and Aptroot 2021). Although P. quassiicola and P. pyrenuloides are phylogenetically close to this new species, they can be distinguished easily by the morphology. P. quassiicola has smaller ascomata (0.3-0.7 mm), smaller ascospores (28-35 (-40) × 12-16 μm) containing colourless oil when over-mature and not inspersed, IKI+ (orange) hamathecium ( Harris 1989). P. pyrenuloides has smaller ascomata (0.5-1.0 mm), larger ascospores (50-62 × 18-24 μm) containing no oil when over-mature and not inspersed, IKI+ (orange) hamathecium ( Harris 1989).

Figures

Figure 2. Pyrenula inspersa (LCUF HN 17058) A thallus with apothecia B apothecia and pseudocyphellae C, F-H ascospores at different developmental stages, over-mature ascospores with orange-oil can be seen in C, F and H D section of apothecium E section visualised with polarised light showing cortex of apothecium with crystals, red stars in D-H show the inspersion in hamathecium I-K young ascospores, red arrows show gelatinous halo. Scale bars: 2 mm (A); 1 mm (B); 10 μm (C, I); 200 μm (D, E); 50 μm (F, H); 35 μm (G); 20 μm (J, K).