Stagonospora samroiyotensis Bhagya. & Phukhams, sp. nov.
Creators: name: Bhagya, Amuhenage T.
name: Phukhamsakda, Chayanard
name: Tanaka, Kazuaki
name: Jones, E. B. Gareth
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Fungi
Ascomycota
Sordariomycetes
Diaporthales
Gnomoniaceae
Stagonospora
Stagonospora samroiyotensis

description: Stagonospora samroiyotensis Bhagya. & Phukhams sp. nov. Fig. 2
Index Fungorum number: IF901771; Facesofungi number: FoF 15567
Etymology:—Name reflects the forest park, Khao Sam Roi Yot where the fungus was collected.
Holotype:— MFLU 24-0020
Saprobic on decaying leaves of Typha sp. Sexual morph: Undetermined. Asexual morph: Conidiomata 240–315 × 170–250 μm, pycnidial, solitary, scattered, semi-immersed to immersed, subglobose to globose, brown to black, central ostiole. Conidiomatal wall 11–18 μm wide, outer layer composed of thick-walled, dark brown cells of textura angularis, internal wall composed with cells of textura angularis, light brown with a hyaline layer of cells of textura prismatica, bearing the conidiogenesis layer. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 10– 11 × 4–6 μm, pyriform to truncate in shape, thin-walled, hyaline, smooth. Conidia 25–32 × 3–4 μm (x̄ = 28.5 × 3.5 μm, n = 30), oblong, cylindrical, 1-septate, constricted at the septa, rounded at the apex and tapered toward the base, guttulate, hyaline, smooth-walled.
Culture characteristics:—Conidia germinated on PDA within 12 hours. Germ tubes produced from the basal cell of the conidia. Colonies growing on PDA, reaching 20–25 mm in 6 weeks at 25 °C. Mycelia superficial, raised with papillate surface, lobate shape with smooth ending at edges, from above pale white from center to the edge; reverse dark brown at the center, orangey at the edge. Light yellow to light orange pigment diffusing in the agar.
Material examined:— THAILAND. Prachuap Khiri Khan Province: Pran Buri District, Khao Sam Roi Yot Wetland on decaying and submerged stem of Typha (Typhaceae) in lotic waters, 25 Feb 2023, Amuhenage T. Bhagya, TBC11 C16 (MFLU 24-0020, holotype); ex-type living culture, MFLUCC 24-0052.
Notes:—In the phylogenetic analyses, Stagonospora samroiyotensis (MFLUCC 24-0052) formed a separate lineage sister to three isolates of S. uniseptata (CBS 135090) with 100% ML and 1.00 BYPP statistic support (Fig. 1). Stagonospora samroiyotensis matches with the general concept of Stagonospora. Our isolate is characterized by having globose pycnidial conidiomata, thick peridial wall composed of textura angularis and textura prismatica cell types, conidiophores reduced to conidiogenous cells with percurrent proliferation from the inner layer of the pycnidial wall. Conidiogenesis cells are doliiform, terminal, and holoblastic producing hyaline, cylindrical to ellipsoidal, straight or slightly curved and guttulate conidia (Li et al. 2016, Quaedvlieg et al. 2013, Tanaka et al. 2015). The conidiomata diameter of S. samroiyotensis is larger (170–250 μm) than S. uniseptata (150 μm), and S. samroiyotensis has a higher L/ W ratio for the conidia (S. samroiyotensis = 8.25, S. uniseptata = 3.67). The conidiomata wall of S. uniseptata consists only of red-brown cells of textura angularis (Quaedvlieg et al. 2013), but S. samroiyotensis has inner hyaline cell layers in textura angularis and textura prismatica. Stagonospora samroiyotensis has pyriform to truncate holoblastic conidiogenous cells while those of S. uniseptata are phialidic. Stagonospora uniseptata conidia are blunt, obtuse, and tapering towards the base with rounded ends (Quaedvlieg et al. 2013), while S. samroiyotensis has more clavate conidia that are tapered and narrow towards the base (Fig. 2). Stagonospora macropycnidia, S. typhoidearum, S. pseudoperfecta and S. typhae have been reported from the same host plant family while S. uniseptata was reported from Carex acutiformis (Quaedvlieg et al. 2013). The host, habitats, and detailed morphological comparison of asexual morph characters between S. samroiyotensis, S. uniseptata, S. macropycnidia, S. typhoidearum, and S. typhae are provided in Table 3. Based on morph-molecular evidence we introduce S. samroiyotensis as a novel species. No sexual stage has been observed.
description: Published as part of Bhagya, Amuhenage T., Phukhamsakda, Chayanard, Tanaka, Kazuaki & Jones, E. B. Gareth, 2024, Morphology and multigene phylogeny reveal a novel Stagonospora species (Massarinaceae, Dothideomycetes) from Thailand, pp. 281-293 in Phytotaxa 644 (4) on page 285, DOI: 10.11646/phytotaxa.644.4.4, http://zenodo.org/record/13214798