Genus

Gesasha

Species

peditatus

Author

Abdel-Wahab & Nagahama, Nova Hedw. 92: 502 (2011)

Class

Sordariomycetes, Subclass Hypocreomycetidae

Order

Microascales

Family

Halosphaeriaceae

Synonymy:

Description

Gesasha Abdel-Wahab & Nagahama, Nova Hedw. 92: 501 (2011)

Type species:

Gesasha peditatus Abdel-Wahab & Nagahama, Nova Hedw. 92: 502 (2011)

Index Fungorum number: Faceoffungi number:

Sexual morph: saprobic, ascomata 200–320 × 260–320 μm, subglobose, elongate, ovate, hyaline to light brown, coriaceous, immersed or erumpent, solitary, ostiolate with a long hyaline neck. Neck 300–800 × 60–90 μm, hyaline, cylindrical, periphysate. Periphyses up to 22 μm in length and 0.5 μm in width. Peridium 20–24 μm wide, consisting of 7–9 layers of thick-walled cells with large lumina, forming textura angularis, cells hyaline except the first outside layer which is brown in color. Catenophyses present. Asci 100–150 × 20–30 μm, unitunicate, clavate with a long stalk, with apical thickening and pore, apically truncate with cytoplasmic retraction, persistent, with eight overlapping biseriate ascospores, developing in a hymenium at base of ascoma venter. Ascospores 18–30 × 9–16 μm, one-septate, subglobose, ellipsoidal or foot-like, with sub-median septum, distoseptate, not constricted at the septa, thick-walled, the walls being 2–2.5 μm thick, hyaline becoming light brown with age, with polar to sub-apical amorphous, ephemeral appendages, smooth. Asexual morph: Undetermined (Description based on Abdel-Wahab & Nagahama (2011)).

Key references:

Abdel-Wahab MA, Nagahama T (2011) Gesasha (HalosphaerialesAscomycota), a new genus with three new species from the Gesashi mangroves in Japan. Nova Hedwigia 92: 497-512.

Campbell J, Anderson JL, Shearer CA (2003) Systematics of Halosarpheia based on morphological and molecular data. Mycologia 95: 530-552.

Jones EBG, Suetrong S, Sakayaroj J, Bahkali AH, Abdel-Wahab MA, Boekhout T, Pang KL (2015) Classification of marine Ascomycota, Basidiomycota, Blastocladiomycota and Chytridiomycota. Fungal Diversity 73: 1-72.

Jones EBG, Ju WT, Lu CL, Guo SY, Pang KL (2017) The Halosphaeriaceae revisited. 60: 453-468l.

Pang KL, Vrijmoed LLP, Kong RYC, Jones EBG (2003) Polyphyly of Halosarpheia (Halosphaeriales, Ascomycota): implications on the use of unfurling ascospore appendages as a systematic character. Nova Hedwigia 77: 1-18.

Shearer CA (1989) Aniptodera (Halosphaeriaceae) from wood in freshwater habitats. Mycologia 81: 139-146.

Maharachchikumbura SSN, Hyde KD, Jones EBG, Mckenzie EHC, Huang SK, Abdel-Wahab MA et al. (2015) Towards a natural classification and backbone tree for Sordariomycetes. Fungal Diversity 72: 199-299.

Volkmann-Kohlmeyer B, Kohlmeyer J (1994) A new Aniptodera (Ascomycotina) from salt march Juncus. Botanica Marina 37: 109-114.

Key to species of Gesasha:

Ascospores one-septate.................................................................................................................................................................2

Ascospores unicellular....................................................................................................................................................................3

2. Ascospores 18–30 × 9–16 μm, subglobose, ellipsoidal or foot-like, with sub-median septum, distoseptate, not constricted at the septa, thick-

walled, hyaline becoming light brown with age, with polar to sub-apical amorphous, ephemeral appendages, smooth......................G. peditatus

Ascospores 16–18 × 8–10 μm, hyaline, ellipsoidal, one-septate, not constricted at the septum, without appendages.................G. mangrovei

Ascospores 8–10(11) × 5–6(7) μm, unicellular, subglobose, ellipsoidal or oval, without appendages, hyaline becoming light brown with age...........................................................................................................................................................................G. unicellularis

Image: Gesasha spp. (a–c) G. peditatus (a) Vertical section through ascoma (b) Apical part of the ascus (c) Ascospore (d–f) G. unicellularis (d) Vertical section through ascoma (e) Apical part of the ascus (f) Ascospore (g–i) G. mangrovei. (g) Vertical section through ascoma. (h) Apical part of the ascus (i) Ascospore. Bars a, d, g=50 μm; b–c, e–f, h–i=5 μm. (Photo plate from Jones et al. 2015).

Type & Location:

Other Specimens:

Substratum:

Dead mangrove wood.

Habitat:

Distribution:

Japan.

Pertinent Literature:

Comments:

NOTES: Gesasha is reminiscent of Aniptodera, however they differ in: (1) phylogenetic distant from each other; (2) the colour of the ascomata (hyaline in Aniptodera); (3) the nature of the ascospore appendages. Ascospore appendages in Aniptodera are polar unfurling type or lacking appendages; (4) shape of the ascospores in Gesasha being globose to widely ellipsoidal while in Aniptodera they are ellipsoidal. The type species of Aniptodera is characterized by hyaline ascomata, asci with distinct pore and wall thickening below the apex and thick-walled ascospores with or without unfurling type of appendages (Shearer 1989). Volkmann-Kohlmeyer & Kohlmeyer (1994) argued that the genus Aniptodera should retained for un-appendaged, thick-walled ascospore producing species. Phylogenetic analyses of ribosomal genes showed that Aniptodera is a polyphyletic genus (Campbell et al. 2003; Pang et al. 2003; Abdel-Wahab and Nagahama 2011, Jones et al. 2017) and many of the fungi currently belonging to the genus have been transferred to new or existing genera. Also, A. chesapeakensis and A. limentica are not monophyletic. The genus is accepted as a member of the Halosphaeriaceae by Jones et al. (2015) and Maharachchikumbura et al. (2015). Several genera of marine ascomycetes have 1-septate ascospores with ephemeral polar appendages, e.g. Aniptodera and Halosarpheia. However, Gesasha peditatus is characterized by its ascospore morphology which includes: distoseptate, thick-walled ascospores with sub-median septum, footlike shape and the amorphous apical to sub-apical ephemeral appendages. Fungi belonging to the Aniptodera/Halosarpheia complex have polar unfurling appendages. Phylogenetic analyses including the LSU rDNA sequence of G. peditatus showed that it formed a clade distant from morphologically similar fungi in Halosphaeriaceae.

Images

Fig 1