Jahnulales » Aliquandostipitaceae

Jahnula

Jahnula Kirschst.

Index Fungorum number: IF2526

 

Saprobic on submerged wood. Sexual morph: Ascomata semi-immersed to erumpent, become superficial with base remaining immersed, solitary or clustered in small groups, globose to subglobose, unilocular, brown to dark brown, membranous, with a stalk-like strand or stoloniferous hyphae attached to the substratum, or covered by sparse hair-like projections, with ostiolate papilla. Peridium variable in thickness, comprising a few layers of relatively large, thin-walled, light brown cells of textura angularis. Pseudoparaphyses cellular, persistent, filiform or hypha- like, hyaline, sparsely septate. Asci 8-spored, bitunicate, fissitunicate, mostly cylindrical, short-pedicellate, with an ocular chamber and sometimes with a faint ring. Ascospores mostly uniseriate, ellipsoid-fusiform, apical cell slightly larger, both cells tapering with rounded ends, reddish brown or dark brown, l-septate, straight or curved (definition sensu stricto from Hawksworth (1984), Hyde and Goh (1999) and Raja and Shearer (2006)). Asexual morph: Undetermined. (Descriptions from Dong et al. 2020)

 

Notes: Jahnula is undoubtedly polyphyletic (Hyde et al. 2013, 2017, 2019; Huang et al. 2018) and Jahnula sensu stricto was mentioned in Huang et al. (2018), and Hyde et al. (2013). Hyde et al. (2013) suggested that taxonomic changes are needed for taxa in Jahnula sensu lato, but more jahnula-like species need to be collected and sequenced. We accept three species, J. aquatica, J. granulosa K.D. Hyde & S.W. Wong and J. rostrata Raja & Shearer in Jahnula sensu stricto, which have been collected from freshwater habitats. These three species share common characters in having dark ascomata with few appendages attached to the base, and ellipsoid-fusiform, brown, l-septate ascospores with wider apical cell (Hawksworth 1984; Hyde and Wong 1999; Raja and Shearer 2006). Asci of J. aquatica are cylindrical, those of J. granulosa are obclavate and those of J. rostrata are clavate. Jahnula aquatica has smooth-walled ascospores without a sheath, while J. granulosa has granular-walled ascospores with a thin mucilaginous sheath. Jahnula rostrata is similar to J. granulosa by rough-walled ascospores but differs in having an irregularly striated pattern. These three species formed a well-supported and stable clade in previous publications (Huang et al. 2018; Hyde et al. 2019).

 

The type species, Jahnula aquatica, commonly occurs in freshwater habitats as listed below. The lectotype of J. aquatica was examined, illustrated and described by Hawksworth (1984). Jahnula aquatica is characterized by ascomata attached to the substratum by subiculum-like hyphae, peridium uneven in thickness, cylindrical asci, elongate-ellipsoid to very broadly fusiform, reddish brown, smooth, moderately thick-walled ascospores without a distinct gelatinous sheath (Hawksworth 1984). The sequences of two isolates R68-1 and R68-2 (not type) were obtained by Raja and Shearer (2006), recognized and used for current phylogenetic analyses (Suetrong et al. 2011; Huang et al. 2018; Hyde et al. 2019).

 

Xylomyces chlamydosporus Goos et al. was considered to be the asexual state of Jahnula aquatica based on fusiform chlamydospores produced in culture (Sivichai et al. 2011). However, the phylogenetic analyses did not support this conclusion because J. aquatica and X. chlamydosporus scattered in different clades within Jahnulales (Campbell et al. 2007; Suetrong et al. 2011).

 

Dong et al. (2020) introduced two new genera Neojahnula and Pseudojahnula to accommodate two known species Jahnula australiensis K.D. Hyde and J. potamophila K.D. Hyde & S.W. Wong, respectively. Seven species, i.e. J. bipolaris, J. guttulaspora, J. queenslandica, J. seychellensis, J. submersa, J. sunyatsenii and J. thailandensis, which are phylogenetically distant from J. aquatica, are transferred to Ascagilis K.D. Hyde. Nine species, i.e. J. apiospora, J. appendiculata, J. bipileata, J. dianchia, J. morakotii, J. poonythii, J. purpurea, J. sangamonensis and J. systyla, are placed in Jahnula sensu lato. For convenience and practicality, we have excluded Jahnula systyla K.D. Hyde & S.W. Wong from the key, because we believe it may be phylogenetically related to Aliquandostipite, pending future phylogenetic studies. (Notes from Dong et al. 2020)

 

Type species: Jahnula aquatica (Kirschst.) Kirschst., Annls mycol. 34(3): 196 (1936)

 

Key to freshwater Jahnula sensu stricto species

1. Ascospores smooth-walled.......................................................... J. aquatica

1. Ascospores rough-walled............................................................................ 2

2. Ascospores granular-walled....................................................... J. granulosa

2. Ascospores with an irregularly striated pattern............................... J. rostrata

 

Key to freshwater Jahnula sensu lato species

1. Ascospores without modification (no appendages/sheath/caps).....................2

1. Ascospores equipped with modification (appendages/sheath/caps)................6

2. Ascospores asymmetric............................................................ J. apiospora

2. Ascospores symmetric................................................................................ 3

3. Ascomata stain substrate purple................................................. J. purpurea

3. Ascomata not as above............................................................................... 4

4. Ascomata with a short but prominent neck, endoasci extend up to 500 μm long in water J. sangamonensis

4. Ascomata with a short papilla, endoasci not extending.................................. 5

5. Ascomata with stalk-like strands attached to the base, with a few sparse hair-like projections J. poonythii

5. Ascomata without any appendages.............................................. J. dianchia

6. Ascospores without unfurling bipolar appendages......................... J. bipileata

6. Ascospores with long unfurling bipolar appendages...................................... 7

7. Ascospores 18–20 × 5–6 μm...................................................... J. morakotii

7. Ascospores 48–55 × 23–26 μm........................................... J. appendiculata

 

References:

Dong W, Wang B, Hyde KD, et al (2020) Freshwater Dothideomycetes. Fungal Divers 105:319–575

Hawksworth DL (1984) Observations on Jahnula Kirschst., a remarkable aquatic pyrenomycete. Sydowia 37, 43–46

Huang SK, Maharachchikumbura SSN, Jeewon R, Bhat DJ et al. (2018) Morphological and molecular taxonomy of Jahnula dianchia sp. nov. (Jahnulales) from submerged wood in Dianchi Lake, Yunnan, China. Mycological Progress 17, 547–555

Hyde KD, Jones EBG, Liu JK, Ariyawansa H et al. (2013) Families of Dothideomycetes. Fungal Diversity 63, 1–313

Hyde KD, Norphanphoun C, Abreu VP, Bazzicalupo A et al. (2017) Fungal diversity notes 603–708: taxonomic and phylogenetic notes on genera and species. Fungal Divers 87, 1–235

Hyde KD, Tennakoon DS, Jeewon R, Bhat DJ et al. (2019) Fungal diversity notes 1036–1150: taxonomic and phylogenetic contributions on genera and species of fungal taxa. Fungal Diversty 96, 1–242

Hyde KD, Wong SW (1999) Tropical Australian freshwater fungi. XV. The ascomycete genus Jahnula, with five new species and one new combination. Nova Hedwigia 68, 489–510

Raja HA, Shearer CA (2006) Jahnula species from North and Central America, including three new species. Mycologia 98, 319–332

Sivichai S, Sri-Indrasutdhi V, Jones EBG (2011) Jahnula aquatica and its anamorph Xylomyces chlamydosporus on submerged wood in Thailand. Mycotaxon 116, 137–142

Suetrong S, Boonyuen N, Pang KL, Ueapattanakit J et al. (2011) A taxonomic revision and phylogenetic reconstruction of the Jahnulales (Dothideomycetes), and the new family Manglicolaceae. Fungal Diversity 51, 163–188

 

 

 

Recent Genus

1
Neochlamydotubeufia
Neohelicomyces

Recent Species

Neohelicomyces submersus
Neohelicomyces hyalosporus
Neohelicomyces grandisporus