Terriera meitanensis J.F. Zhang & Z.Y. Liu, 2020

Zhang, Jin-Feng, Liu, Jian-Kui, Hyde, Kevin D., Ekanayaka, Anusha H. & Liu, Zuo-Yi, 2020, Morpho-phylogenetic evidence reveals new species in Rhytismataceae (Rhytismatales, Leotiomycetes, Ascomycota) from Guizhou Province, China, MycoKeys 76, pp. 81-106 : 81

Terriera meitanensis J.F. Zhang & Z.Y. Liu sp. nov. Figure 4

Holotype.

MFLU 18-2299.

Etymology.

Referring to the locality of the holotype, Meitan County, Guizhou Province, China.

Description.

Apothecia developing on dead stems (Fig. 4a ), semi-immersed to superficial, elliptical or oblong-elliptical, ends slightly acute to obtuse, surface black, matt, raising the substratum surface, opening by a single longitudinal split that extends nearly the entire length (Fig. 4b, c ). In median vertical section (Fig. 4d ), apothecia deeply embedded in host tissue, with host cells becoming filled with fungal tissue as the apothecium develops. Covering stroma (Fig. 4e ) 33-42 µm thick, composed of blackish-brown, thick-walled cells that are fused with host tissue in the outermost layers, becoming pale pigmented or nearly colourless towards the hymenium, thin-walled cells, arranged in textura angularis or textura globulosa. Along the upper edge of the apothecial opening, there is a flattened, 19-34 µm thick extension adjacent to the covering stroma that is composed of strongly melanised tissue with no obvious cellular structure. Basal stroma (Fig. 4g ) 8-18 µm thick, dark-brown or blackish-brown, composed of angular to globose, thick-walled cells, 2.5-4 µm diam. Where the covering stroma meets the basal stroma, there is a triangular-shaped, 35-60 µm thick, tissue composed of thin-walled, hyaline to pale brown cells forming a textura prismatica (Fig. 4f ). Subhymenium 12-16 µm thick, consisting of hyaline textura angularis to textura intricata. Paraphyses 1-2 µm, filiform, hyaline, septate, gradually swollen or branching once at the apex, embedded in gelatinous matrix, anastomosing at the base. Asci (98.5-)113-125.5(-131.5) × 6-7.5 µm (x ¯ = 117 × 6.5 µm, n = 20), 8-spored, unitunicate, cylindrical, somewhat long-stalked, thin-walled, apex generally truncate, J-, without circumapical thickening. Ascospores 47-54.5 × 1.5-2.5 µm (x ¯ = 50.5 × 2 µm, n = 35), fascicle, filiform, gradually tapering towards the ends, hyaline, aseptate, smooth-walled, straight or slightly curved, lacking a gelatinous sheath. Asexual morph: Not observed.

Material examined.

CHINA, Guizhou Province, Zunyi, Meitan County, dead stems of unidentified host, 28 August 2017, J.F. Zhang, MT-1 (MFLU 18-2299, holotype); ibid. (GZAAS 19-1731, isotype).

Notes.

In our phylogenetic analysis (Fig. 1 ), Terriera meitanensis is placed in a robust clade with T. camelliicola , T. elliptica , T. karsti and T. thailandica by strong statistical support (MPBP 100% and BYPP 1.00). Terriera meitanensis has larger asci than T. camelliicola and T. thailandica , while the ascospores of T. meitanensis are smaller ( Johnston 2001; Hyde et al. 2016). Both T. meitanensis and T. karsti share similar-sized asci, but T. karsti has larger ascospores (47-54.5 × 1.5-2.5 µm vs. 55-66 × 1.5-2.0 µm). Terriera meitanensis differs from T. elliptica by its obviously smaller asci (113-122.5 × 6-7.5 µm vs. 135-175 × 7-9 µm) and ascospores (47-54.5 × 1.5-2.5 µm vs. 60-85 × 1.5-2 µm) ( Zhang et al. 2015). Moreover, the ascospores of T. camelliicola and T. elliptica are enveloped by a gelatinous sheath, respectively, while this is not observed in T. meitanensis . In addition, the comparison of the ITS gene region is processed between T. meitanensis and its closest species T. elliptica , based on the recommendations from Jeewon and Hyde (2016) and the results showed that there are 15/489 bp (3%) differences. Therefore, we introduce T. meitanensis herein as a new species, based on morphological and molecular evidence.

Figures

Figure 1. Phylogram of Rhytismataceae is presented as the best tree revealed by MP analysis, based on the concatenated LSU-ITS-mtSSU sequence dataset. MP bootstrap support values (MPBP ≥ 50 %) and Bayesian inference posterior probabilities (BYPP ≥ 0.95) are shown near the nodes. The tree is rooted to Marthamyces emarginatus (ICMP 22854), the scale bar showing 10 changes. Type strains are indicated in bold and new sequences, generated in this study, are given in red.

Figure 4. Terriera meitanensis a habit of apothecia on substrate b, c apothecia observed under the dissecting microscope in face view d vertical section through an apothecium e covering stroma f triangular space in section between the covering stroma and basal stroma g basal stroma h paraphyses with anastomoses amongst asci in various states of maturity i, j immature asci k, l ascospores. Note: d-l mounted in water. Scale bar: 1 cm (a), 1 mm (b), 500 µm (c), 100 µm (d), 10 µm (e, g, k, l), 30 µm (f), 20 µm (h-j).