Terriera karsti J.F. Zhang & J.K. 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 karsti J.F. Zhang & J.K. Liu sp. nov. Figure 3

Holotype.

MFLU 18-2288.

Etymology.

Refers to the karst landscape where the holotype was collected.

Description.

Apothecia developing on dead branch, elliptical or oblong-elliptical in outline, ends slightly acute to obtuse. Apothecia surface black, matt or slightly glossy, moderately raising the substratum surface, opening by a single longitudinal split that extends to the ends of the apothecium (Fig. 3a, b ). Lips absent. In median vertical section (Fig. 3d ), apothecia deeply embedded in host tissue, with host cells becoming filled with fungal tissue as the apothecium develops. Covering stroma (Fig. 3c ) 30-45 µm thick, composed of blackish-brown to black, thick-walled cells of textura angularis towards the exterior and several layers of pale to nearly hyaline, thin-walled cells towards the interior. Along the edge of the apothecial opening, there is a flattened, 12-20 µm thick extension adjacent to the covering stroma that is composed of strongly melanised tissue with no obvious cellular structure. Basal stroma 8-18 µm thick, dark brown or blackish-brown, composed of angular to globose, thick-walled cells, 2.5-4 µm diam. A triangular space between the covering stroma and basal stroma consists of thin-walled, nearly hyaline to grey-brown cells arranged in textura prismatica. Paraphyses 1-2 µm, filiform, hyaline, septate, gradually swollen or branching once at the apex, embedded in gelatinous sheaths. Asci (103-)110-122.5 × 5.5-7 µm (x ¯ = 113 × 6 µm, n = 20), 8-spored, unitunicate, cylindrical, long stalk, thin-walled, apex truncate to somewhat round, J-, without circumapical thickening. Ascospores 55-66 × 1.5-2.0 µm (x ¯ = 61 × 1.8 µm, n = 25), fascicle, but not coiled, filiform, gradually tapering toward the ends, hyaline, aseptate, smooth-walled, straight or slightly curved, lacking gelatinous sheath. Asexual morph: Not observed.

Culture characteristics.

Colonies on PDA reaching 51 mm after 14 days at 25 °C, irregular in shape, cottony with moderately dense, fluffy aerial mycelium. At first, white, becoming slightly greyish in the centre, reverse side bronze in the centre and pale towards the edge.

Material examined.

CHINA, Guizhou Province, Guiyang, Yunyan District, dead branch of unidentified ligneous plants, 6 May 2016, J.F. Zhang, SH-06 (MFLU 18-2288, holotype); ibid. (GZAAS 19-1720, isotype); ex-type living culture, GZCC 19-0047.

Notes.

In the present study (Fig. 1 ), Terriera karsti is phylogenetically close to T. camelliicola and T. thailandica with moderate support (MPBP 63% and BYPP 1.00). Terriera karsti is not significantly distinguished from T. camelliicola , based only on morphological characters as they share similar-sized asci (110-122.5 × 5.5-7 µm vs. 85-120 × 5.5-6.5 µm) and ascospores (55-66 × 1.5-2 µm vs. 50-70 × 1 µm) ( Johnston 2001). However, the ascospores of T. camelliicola are covered by a 0.5 µm wide gelatinous sheath, while this is not observed in T. karsti (Sharma 1982). In order to clarify their affinity, the recommendations of species delineation from Jeewon and Hyde (2016) were followed and the comparison of each gene region between these two taxa is processed and showed that there are 9/840 bp (1%) and 10/694 bp (14.4%) differences in LSU and mtSSU regions, respectively, while T. karsti can be easily differentiated from T. thailandica by its larger asci (110-122.5 × 5.5-7 µm vs. 80-105 × 3.4-6.6 µm) and ascospores (55-66 × 1.5-2 µm vs. 38-60 × 1-1.5 µm) ( Hyde et al. 2016). A comparison of the LSU gene region between these two taxa has also been processed and the result showed that there are 3/838 bp (base pair) differences. Based on phylogenetic analyses, coupled with morphological distinction, Terriera karsti is introduced herein as a new species.

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 3. Terriera karsti a, b apothecia observed under the dissecting microscope c detail of covering stroma in vertical section d vertical section through an apothecium e, f asci in various states of maturity g apices of paraphyses h, i ascospores. Note: c-i mounted in water. Scale bar: 1 mm (a), 500 µm (b), 20 µm (c, e, f), 100 µm (d), 10 µm (g, i).