Fungalpedia – Note 2477, Isthmosporella

 

Isthmosporella Shearer & Crane

Citation when using this data: Dong W et al. 2020 – Fungalpedia, Ascomycota.

Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1

Classification: Phaeosphaeriaceae, Pleosporales, Pleosporomycetidae, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi

Saprobic on submerged wood. Sexual morph: Ascomata scattered on natural substrate, immersed to superficial, globose, oblique, black, glabrous, membranous, rostrate. Neck short, cylindrical, periphysate. Peridium 2-layered, outer layer composed of brown, fusoid-cylindric pseudoparenchyma cells, inner layer composed of compressed, subhyaline to light brown, fusoid cells. Pseudoparaphyses sparse, cellular, broad, hyaline, septate. Asci 8-spored, bitunicate, fissitunicate, ventricose to clavate, broadly rounded at the apex, without an apical apparatus or oculus, short pedicellate. Ascospores 3- to 4-seriate, cylindrical to fusoid, isthmoid at center, tapering at both ends, straight to slightly curved, hyaline, phragmoseptate, constricted at septa, surrounded by a gelatinous sheath (Shearer and Crane 1999). Asexual morph: Undetermined.

Notes: The monotypic genus Isthmosporella, typified by I. pulchra Shearer & Crane, was collected from submerged, decorticated wood in USA (Shearer and Crane 1999). It was initially placed in Phaeosphaeriaceae based on its small, globose ascomata, relatively undifferentiated peridium of small pseudoparenchymatic cells, and sparse pseudoparaphyses (Shearer and Crane 1999). However, the ventricose to clavate asci, cylindrical to fusoid ascospores with isthmoid at center do not fit with the familial concept of Phaeosphaeriaceae (Hyde et al. 2013). It is placed in Pleosporales genera incertae sedis (Wijayawardene et al. 2018, 2020), until its DNA data are obtained. One collection of Isthmosporella pulchra (A254-2), collected from the type locality by its author (Dr. Lee Crane), is illustrated here.

Type species: Isthmosporella pulchra Shearer & Crane.

Other accepted species: Species Fungorum – search Isthmosporella.

 

image

 

Figure 1 – Isthmosporella pulchra (Material examined: USA, New York, Adirondack Park, Piercefield, Tupper Lake at public boat launch from Rt. 30, UTM Zone 18, on submerged, decorticated wood, A254-2). a Squash mount of ascoma. b Bitunicate ascus. c, d Ectotunica rupturing at the apex and becoming strongly wrinkled and curled inwards. e Pseudoparaphyses. f, h Ascospores. Note gelatinous sheath with a dense region near the isthmus (arrowed in f). g Ascospore in glycerin. Scale bars: a = 100 µm, b–h = 20 µm.

 

References

Hyde KD, Jones EBG, Liu JK, Ariyawansa H, Boehm E, Boonmee S, Braun U, Chomnunti P, Crous PW, Dai DQ, Diederich P, Dissanayake A, Doilom M, Doveri F, Hongsanan S, Jayawardena R, Lawrey JD, Li YM, Liu YX, Lücking R, Monkai J, Muggia L, Nelsen MP, Pang KL, Phookamsak R, Senanayake I, Shearer CA, Suetrong S, Tanaka K, Thambugala KM, Wijayawardene NN, Wikee S, Wu HX, Zhang Y, Aguirre-Hudson B, Alias SA, Aptroot A, Bahkali AH, Bezerra JL, Bhat DJ, Camporesi E, Chukeatirote E, Gueidan C, Hawksworth DL, Hirayama K, Hoog SD, Kang JC, Knudsen K, Li WJ, Li XH, Liu ZY, Mapook A, McKenzie EHC, Miller AN, Mortimer PE, Phillips AJL, Raja HA, Scheuer CH, Schumm F, Taylor JE, Tian Q, Tibpromma S, Wanasinghe DN, Wang Y, Xu JC, Yan JY, Yacharoen S, Zhang M 2013 – Families of Dothideomycetes. Fungal Divers 63:1–313.

Shearer CA, Crane JL 1999 – Freshwater Ascomycetes: Isthmosporella pulchra gen. et sp. Mycologia 91:141–144.

Wijayawardene NN, Hyde KD, Lumbsch HT, Liu JK, Maharachchikumbura SSN, Ekanayaka AH, Tian Q, Phookamsak R 2018 – Outline of Ascomycota: 2017. Fungal Divers 88:167–263.

Wijayawardene NN, Hyde KD, Al-Ani LKT, Tedersoo L, Haelewaters D, Rajeshkumar KC, Zhao RL, Aptroot A, Leontyev DV, Saxena RK, Tokarev YS, Dai DQ, Letcher PM, Stephenson SL, Ertz D, Lumbsch HT, Kukwa M, Issi IV, Madrid H, Phillips AJL, Selbmann L, Pfliegler WP, Horváth E, Bensch K, Kirk PM, Kolaříková K, Raja HA, Radek R, Papp V, Dima B, Ma J, Malosso E, Takamatsu S, Rambold G, Gannibal PB, Triebel D, Gautam AK, Avasthi S, Suetrong S, Timdal E, Fryar SC, Delgado G, Réblová M, Doilom M, Dolatabadi S, Pawłowska J, Humber RA, Kodsueb R, Sánchez-Castro I, Goto BT, Silva DKA, de Souza FA, Oehl F, da Silva GA, Silva IR, Błaszkowski J, Jobim K, Maia LC, Barbosa FR, Fiuza PO, Divakar PK, Shenoy BD, Castañeda-Ruiz RF, Somrithipol S, Lateef AA, Karunarathna SC, Tibpromma S, Mortimer PE, Wanasinghe DN, Phookamsak R, Xu J, Wang Y, Tian F, Alvarado P, Li DW, Kušan I, Matočec N, Maharachchikumbura SSN, Papizadeh M, Heredia G, Wartchow F, Bakhshi M, Boehm E, Youssef N, Hustad VP, Lawrey JD, Santiago ALCMA, Bezerra JDP, Souza-Motta CM, Firmino AL, Tian Q, Houbraken J, Hongsanan S, Tanaka K, Dissanayake AJ, Monteiro JS, Grossart HP, Suija A, Weerakoon G, Etayo J, Tsurykau A, Vázquez V, Mungai P, Damm U, Li QR, Zhang H, Boonmee S, Lu YZ, Becerra AG, Kendrick B, Brearley FQ, Motiejūnaitė J, Sharma B, Khare R, Gaikwad S, Wijesundara DSA, Tang LZ, He MQ, Flakus A, Rodriguez-Flakus P, Zhurbenko MP, McKenzie EHC, Stadler M, Bhat DJ, Liu JK, Raza M, Jeewon R, Nassonova ES, Prieto M, Jayalal RGU, Erdoğdu M, Yurkov A, Schnittler M, Shchepin ON, Novozhilov YK, Silva-Filho AGS, Liu P, Cavender JC, Kang Y, Mohammad S, Zhang LF, Xu RF, Li YM, Dayarathne MC, Ekanayaka AH, Wen TC, Deng CY, Pereira OL, Navathe S, Hawksworth DL, Fan XL, Dissanayake LS, Kuhnert E, Grossart HP, Thines M 2020 – Outline of Fungi and fungus-like taxa. Mycosphere 11:1060–1456.

 

Entry by

Wei Dong, Faculty of Agriculture and Food, Kunming University of Science and Technology, Kunming 650500, China, Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand, Innovative Agriculture Research Center, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, Institute of Plant Health, Zhongkai University of Agriculture and Engineering, Haizhu District, Guangzhou 510225, China

 

Published online 15 May 2026

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