Dermatodothella Viégas, Bragantia

Ariyawansa, Hiran A., Kang, Ji-Chuan, Alias, Siti A., Chukeatirote, Ekachai & Hyde, Kevin D., 2013, Towards a natural classification of Dothideomycetes: The genera Dermatodothella, Dothideopsella, Grandigallia, Hysteropeltella and Gloeodiscus (Dothideomycetes incertae sedis), Phytotaxa 147 (2), pp. 35-47 : 36-38

Dermatodothella Viégas, Bragantia 4(1–6): 150. 1944.

MycoBank: MB 1472

Parasitic on leaves in terrestrial habitats. Ascostromata superficial to semi-immersed, globose to subglobose, with two to numerous locules. Locules globose to subglobose, with individual central ostioles. Ostioles usually widely porate, with well-developed neck, ostiolar canal filled with periphyses. Peridium of locules thin-walled, heavily pigmented, small, dark brown to black cells of textura angularis. Hamathecium composed of filiform pseudoparaphyses. Asci 8- spored, fissitunicate, clavate to sub-cylindrical, with a short, broad, furcate pedicel with an ocular chamber. Ascospores 2–3 overlapping seriate, fusoid with broadly rounded ends, hyaline, 1-septate, constricted at the septa when immature. Asexual state: unknown.

Type species: Dermatodothella multiseptata Viegas, Bragantia 4(1–6): 150 (1944) MycoBank: MB 286052. FIG.1 A–P .

Parasitic on leaves in terrestrial habitats. Ascostromata black, well-developed, superficial to semi-immersed, globose to subglobose, with two to numerous locules, cells of ascostromata comprising brown-walled cells of textura angularis. Locules 70–100× 200–250 µm (x = 90× 210 µm, n = 10) diam, globose to subglobose, with individual central ostioles. Ostioles usually widely porate, with well-developed neck, ostiolar canal filled with a tissue of hyaline cells. Peridium of locules 10–15 µm diam (x = 10, n = 10), comprising one layer of thinwalled, heavily pigmented, small, dark brown to black cells of textura angularis. Hamathecium composed of dense, 1–3 µm diam (x = 2, n = 20), filiform, septate, hyaline pseudoparaphyses. Asci 55–70× 15–20 µm (x = 65× 16 µm, n = 20), 8-spored, bitunicate, fissitunicate, clavate to sub-cylindrical, with a short, broad, furcate pedicel, apically thickened and rounded, with an ocular chamber. Ascospores 17–25× 5–6 µm (x = 20× 5 µm, n = 40), 2–3 overlapping seriate, fusoid with broadly rounded ends, hyaline, 1-septate, constricted at the septa when immature. Asexual state: unknown.

Notes: Dermatodothella was introduced by Viégas (1944) as a monotypic genus and typified by Dermatodothella multiseptata . It is characterized by multi-loculate ascostromata, with filiform pseudoparaphyses and fusoid ascospores with 5 − 7 septa at maturity. Dermatodothella has similarities with Polystomellaceae . Dermatodothella and the generic type of Polystomellaceae , Dothidella share similar characters such as having multi-loculate, globose to subglobose ascostromata, with widely porate ostioles. However Dermatodothella differs from Dothidella in having filiform pseudoparaphyses and multi-septate ascospores, while Dothidella has bi-celled ascospores and lacks pseudoparaphyses ( Hyde et al. 2013) Munkiella and Dermatodothella share similar characters in having multi-loculate ascostromata with widely porate ostioles and clavate to subcylindrical asci, but differ in the position of the ascostromata on host (semi immersed versus superficial) and the nature of pseudoparaphyses (cellular versus filiform) Parastigmatea differs from Dermatodothella in having immersed ascostromata covered by cuticle or epidermis while Dermatodothella has superficial ascostromata ( Hyde et al. 2013) We place Dermatodothella in Polystomellaceae because of its similarities with other genera in this family.

We only observed immature spores. The description of the mature spores is based on the original description, as follows “ ascospores 5–7 septate at maturity, constricted at the septum, smooth to verruculose, thick-walled without a sheath” ( Viégas 1944)

Material examined: Brazil, São Paulo, Campinas , on leaves of Mikania sp. , 5 December 1943, A.P. Viégas (IAC, paratype)

Phaeosphaeriaceae M.E. Barr, Mycologia 71(5): 948. 1979.

Barr (1979) introduced Phaeosphaeriaceae which is typified by Phaeosphaeria oryzae , which has immersed to superficial ascomata with short papillate or rostrate ostioles and hyaline, ellipsoidal to fusiform or filiform, yellowish or brown ascospores. Zhang et al. (2012) included 18 genera in Phaeosphaeriaceae based on the multi-gene analysis of LSU, SSU, RBP2 and EF-1 sequence data. Phaeosphaeriaceae shares similarities with Leptosphaeriaceae , but can clearly be differentiated by the characters of the peridium, host and the asexual state. Phaeosphaeriaceae species are generally associated with monocotyledons and the peridium comprises a thin layer of pseudoparenchymatous cells and produces Amarenographium , Ampelomyces , C haetosphaeronema, Coniothy rium, Hende rsonia, Neose tophoma, Paraphoma , Phaeoseptoria , Rhabdospora , Scolecosporiella , Setophoma , Sphaerellopsis and Tiarospora asexual states. Leptosphaeriaceae usually occurs on dicotyledons, has a peridium of scleroplectenchymatous cells, and asexual states are known as Coniothyrium and Phoma ( Câmara et al. 2002, De Gruyter et al. 2012, Hyde et al. 2013, Kirk et al. 2008; Zhang et al. 2009, 2012)

Figures

FIGURE 1. Dermatodothella multiseptata (isotype). A. Appearance of the fungus on herbarium material B. Ascostromata on substrate C. Close up of ascostroma. D-F. Section of ascostroma. G. Ostiole with well-developed neck. H. Close up of locule wall. I. Arrangement of asci inside the ascostroma. J. Filiform, septate, hyaline pseudoparaphyses. K. Immature ascus with 8 ascospores. L– M. Asci stained in cotton blue reagent. N–P. Immature ascospores with smooth walls (stained in cotton blue reagent). Scale Bars: D– G = 20 µm, H–K = 15 µm, L–M = 5 µm