Hydeomyces desertipleosporoides Maharachch., Ariyawansa, Wanas. & Al-Sadi, 2019

Maharachchikumbura, Sajeewa S. N., Ariyawansa, Hiran A., Wanasinghe, Dhanushka N., Dayarathne, Monika C., Al-Saady, Nadiya A. & Al-Sadi, Abdullah M., 2019, Phylogenetic classification and generic delineation of Hydeomyces desertipleosporoides gen. et sp. nov., (Phaeosphaeriaceae) from Jebel Akhdar Mountain in Oman, Phytotaxa 391 (1), pp. 28-38 : 34-35

Hydeomyces desertipleosporoides Maharachch., Ariyawansa, Wanas. & Al-Sadi , sp. nov.

MycoBank number: MB 827329; Facesoffungi number: FoF 05382; FIGURE 2 .

Etymology: The species epithet is from the combination of two words “ desertum” (desert) and “ pleosporoides” similar to Pleospora

Habitat terrestrial, saprobic on dead barks of Juniperus excels M. bieb. Sexual morph: Ascomata 240–280 × 260–300 μm (x = 260 × 280 μm, n = 10), semi-immersed to erumpent in woody tissue, solitary or rarely confluent, globosedepressed, brown to black; apex with a central coriaceous, papillate ostiolar perforation, without periphyses. Peridium 35–60 μm thick (x = 45 μm n = 10), with 2–5 layers, comprising heavily pigmented, thin-walled, brown to dark brown cells of textura angularis-globosa. Hamathecium comprising 1.5–2.5 μm (x = 2 μm, n = 10) wide, long, filamentous, branched, septate, pseudoparaphyses. Asci 70–85 × 9–17 μm (x = 75 × 12.5 μm, n = 15) arising from basal and lateral cavity surface of the ascoma, 8-spored, bitunicate, fissitunicate, cylindrical, thick walled at the apex, with a short, bulbous pedicel, rounded at the apex, with a minute ocular chamber. Ascospores 10–15 × 5–6.5 μm (x = 13.5 × 5.8 μm, n = 50)

partially overlapping or obliquely uniseriate, ellipsoidal to subfusiform, muriform, upper part wider than the lower part, 2–

4-transversely septate, with 1 vertical septum, deeply constricted at the central septum, initially hyaline, becoming brown at maturity, with rounded ends, lower end cone-shaped, lacking mucilaginous sheath. Asexual morph: Pycnidia 35–80 × 30–45 μm (x = 50 × 35 μm, n = 10) initially hyaline transparent or brown becoming dark brown with age, globose,

glabrous with a narrow ostiolum. pycnidial wall composed of textura angularis. Conidiophores absent; conidiogenous cells hyaline, ampulliform and lining the pycnidial cavity. Conidia 4–8.5 × 1.8–3 μm (x = 5.8 × 2.1 μm, n = 50) hyaline,

smooth-walled, aseptate, straight or slightly curved, ovoid, apex round.

Culture characters: Colonies on PDA slow growing, reaching 4 cm within 15 days, glabrous and colourless at the margin becoming yellowish green to olivaceous green towards the center with whitish aerial mycelium.

Materials examined: Sultanate of Oman, Al Jabal al-Akhdar (Green Mountain), from dead barks of Juniperus excels ( Cupressaceae ), 07.2016, SSN Maharachchikumbura OM13 (SQU H-101, holotype), ex-type culture SQUCC

15259); ibid., 04.2017, SSN Maharachchikumbura ( OM136 , paratype), (culture SQUCC 15260 ) .

Notes: Taxa in Dematiopleospora and Dlhawksworthia show a close phylogenetic affinity to Hydeomyces desertipleosporoides in ML and BI analyses. The morphological characteristics of Hydeomyces desertipleosporoides such as the globose ascomata, cylindrical asci with minute ocular chamber, muriform, yellowish-brown to brown ascospores resemble those in species of Dematiopleospora and Dlhawksworthia . One might argue that a close morphological relatedness (muriform nature) in ascospores between these genera could be indicative of the same genus.

However, a close morphological comparison with Hydeomyces desertipleosporoides and taxa in these mentioned genera reveal that the latter has noteworthy differences which can segregate them into different generic accounts. Hydeomyces desertipleosporoides lack setae/periphyses in the ostiolar region and 2–4-transverse septa with 1 vertical septum in the ascospores, whereas Dematiopleospora have an ostiole comprising prominent dark brown setae/periphyses and ascospores with>4-transverse septa and 1–2 vertical septa ( Wanasinghe et al. 2014, Hyde et al. 2016). Furthermore,

ascospores of Dematiopleospora are arranged as overlapping bi-seriate, while Hydeomyces desertipleosporoides has partially overlapping or obliquely uni-seriate asci. To further support establishment of the new taxon as proposed by

Jeewon and Hyde (2016), we delved into nucleotide differences within both rRNA and protein coding gene regions.

Comparison of the 534 nucleotides across the ITS regions (ITS1-5.8S-ITS2) reveals 63 bp (11.8%) differences including the gaps, 819 bp of the LSU rDNA region reveals 14 bp (1.7%) differences including the gaps, the 981 bp of the SSU rDNA region reveals 12 bp (1.22%) differences between Dematiopleospora and Hydeomyces and examination of the 869 bp of the TEF region reveals 26 bp (3%) differences. Also, the Dlhawksworthia spp. and Hydeomyces desertipleosporoides are morphologically distinguishable with respect to their asexual morphs. The asexual morph of

Hydeomyces desertipleosporoides is distinct from taxa in the genus Dlhawksworthia in having phoma -like, hyaline,

smooth-walled, aseptate and cylindrical conidia, whereas in Dlhawksworthia conidia are camarosporium-like, brown,

muriform, ellipsoidal or sometimes slightly sigmoidal.

Figures

FIGURE 2 Hydeomyces desertipleosporoides (SQU H-101, holotype) a Ascostromata on substrate. b, c Ascoma in vertical section. d Peridium. e Periphyses. f–j Asci k–n Ascospores. o Cultures on PDA. p Pycnidium on PDA. q–s Pycnidia. t Conidia. Scale bars b, q–s = 50 μm, b = 100 μm, e, t = 20 μm, k–n = 10 μm. Scale bar of b applies to b–c. Scale bar of e applies to e–j.