Pleosporales » Astrosphaeriellaceae

Pithomyces

Pithomyces Berk. & Broome

 

Saprobic in terrestrial or freshwater habitats. Sexual morph: Ascomata dark opaque, solitary to gregarious, erumpent to superficial, mammiform to conical, with ruptured, reflexed, stellate, host remnants around the base, uniloculate, glabrous, brittle, carbonaceous, with an indistinct ostiole. Peridium unequal thickness, poorly developed at the base, composed of thick, dark brown to black cells. Pseudoparaphyses dense, trabeculate, filiform, hyaline, sparsely septate. Asci 8-spored, bitunicate, fissitunicate, cylindrical, with furcate pedicel, apically rounded. Ascospores overlapping biseriate, pale brown to dark brown, fusiform with acute ends, septate, smooth-walled (Pratibha and Prabhugaonkar 2015; Wanasinghe et al. 2018). Asexual morph: Hyphomycetous. Conidiophores mononematous, micronematous, mostly intercalary, sometimes denticulate, aseptate. Conidiogenous cells mono or polyblastic, hyaline to light brown, smooth. Conidia solitary, brown to black, obovate to oblong, verruculose to spinulose, transversely septate (Pratibha and Prabhugaonkar 2015; Wanasinghe et al. 2018).

 

Type species: Pithomyces flavus Berk. & Broome

 

Notes: Pithomyces is similar to Astrosphaeriellaceae members in having dark, carbonaceous ascomata with a poorly developed base and fusiform ascospores (Liu et al. 2011; Phookamsak et al. 2015; Wanasinghe et al. 2018; Jayasiri et al. 2019). Pithomyces clustered in Astrosphaeriellaceae with low bootstrap support (Jayasiri et al. 2019; Dong et al. 2020), but morphologically belongs to Astrosphaeriellaceae.

 

Over 40 epithets are listed in Index Fungorum (2020), but only three have sequence data, viz. Pithomyces caryotae Wanas. et al., P. flavus and P. licualae Wanas. et al. Pithomyces flavus was found on the natural substratum associated with its sexual morph Astrosphaeriella vesuvius, which was confirmed in the phylogenetic analysis (Pratibha and Prabhugaonkar 2015). Wanasinghe et al. (2018) found the asexual morphs of P. caryotae and P. licualae from culture, respectively. The asexual morphs of three species share similar morpholigical characters in having obovate, septate, pigmented and rough-walled conidia (Pratibha and Prabhugaonkar 2015; Wanasinghe et al. 2018). Pithomyces flavus was recorded from freshwater habitats (Cai et al. 2002; Hu et al. 2013), but not confirmed by molecular data. (Notes from Dong et al. 2020)

 

List of freshwater Pithomyces species

*Pithomyces flavus Berk. & Broome, J. Linn. Soc., Bot. 14(no. 74): 100 (1873) [1875]

Basionym: Sphaeria vesuvius Berk. & Broome, J. Linn. Soc., Bot. 14(no. 74): 127 (1873) [1875]

Synonymy: Astrosphaeriella vesuvius (Berk. & Broome) D. Hawksw. & Boise, Sydowia 38: 122 (1986) [1985]

Freshwater distribution: China (Cai et al. 2002; Hu et al. 2013)

 

References

Cai L, Tsui CKM, Zhang KQ, Hyde KD (2002) Aquatic fungi from Lake Fuxian, Yunnan, China. Fungal Divers 9:57–70

Dong W, Wang B, Hyde KD, McKenzie EHC, Raja HA, Tanaka K, Abdel-Wahab MA, Abdel-Aziz FA, Doilom M, Phookamsak R, Hongsanan S, Wanasinghe DN, Yu X-D, Wang G-N, Yang H, Yang J, Thambugala KM, Tian Q, Luo Z-L, Yang J-B, Miller AN, Fournier J, Boonmee S, Hu D-M, Nalumpang S, Zhang H (2020) Freshwater Dothideomycetes. Fungal Divers 105:319–575

Hu DM, Liu F, Cai L (2013) Biodiversity of aquatic fungi in China. Mycology 4:125–168

Jayasiri SC, Hyde KD, Jones EBG, McKenzie EHC, Jeewon R, Phillips AJL, Bhat DJ, Wanasinghe DN, Liu JK, Lu YZ, Kang JC, Xu JC, Karunarathna SC (2019) Diversity, morphology, and molecular phylogeny of Dothideomycetes on decaying wild seed pods and fruits. Mycosphere 10:1–186

Liu JK, Phookamsak R, Jones EBG, Zhang Y, Ko-Ko TW, Hu HL, Boonmee S, Doilom M, Chukeatirote E, Bahkali AH, Wang Y, Hyde KD (2011) Astrosphaeriella is polyphyletic, with species in Fissuroma gen. nov., and Neoastrosphaeriella gen. nov. Fungal Divers 51:135–154

Phookamsak R, Norphanphoun C, Tanaka K, Dai DQ, Luo ZL, Liu JK, Su HY, Bhat DJ, Bahkali AH, Mortimer PE (2015) Towards a natural classification of Astrosphaeriella-like species; introducing Astrosphaeriellaceae and Pseudoastrosphaeriellaceae fam. nov. and Astrosphaeriellopsis, gen. nov. Fungal Divers 74:143–197

Pratibha J, Prabhugaonkar A (2015) Multi-gene phylogeny of Pithomyces with the sexual morph of P. flavus Berk. & Broome. Phytotaxa 218:84–90

Wanasinghe DN, Jeewon R, Jones EBG, Boonmee S, Kaewchai S, Manawasinghe IS, Lumyong S, Hyde KD (2018) Novel palmicolous taxa within Pleosporales: multigene phylogeny and taxonomic circumscription. Mycol Prog 17:571–590

 

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