[Notes from Kew Type specimen, PRJ 2010] Kew images.

Microsphaeropsis onychiuri (Punithalingham) Morgan-Jones comb. nov.
= Coniothyrium onychiuri Punithalingham, Trans. Br. Mycol. Soc. 55: 497, 1970

Another isolate IMI 137447 also made from Onychiurus pseudofimetarius from New Zealand by Mrs J. Young was identical to the type.

Colony on potato dextrose agar grey brown, eventually turning black with sparse aerial mycelium. Mycelium composed of septate, branched, dark brown, smooth to verrucoluse hyphae 2-4 µm thick. Pycnidia solitary spherical to subglobose, 100-140 µm diam, dark brown to black, opening by wide, apical ostioles. Pycnidial wall 2-4 cell layers thick, composed of brown compressed cells heavily pigmented and thick-walled on the outside. Conidiophores hyaline, simple, non-septate, obpyriform to clavate 3-5 x 2-3 µm. Pycnidiospores (phialospores), sphaeroid pale-brown, verruculose, 3-4 x 2-3.5 µm.

Coloniae in agaro 'potato-dextrose' fusco-griseae denique nigrae mycelio sparso aereo. Mycelium ex hyphis septatis, ramosis, brunneis, laevibus vel verrucuooaas 2-4 µm crassis compositum. Pycnidia solitaria, sphaerica vel subglobosa, 100-140 µm diam, fusca vel nigra, per ostiolum apicale aperientia. Paries pycnidialis 2-4-stratosus cellularum compositus, cellulis brunneis, compressis, extra obscuris et crassoparietalibus. Conidiophora hyalina, simplicia, continua, obpyriformia vel clavata, 3-5 x 2-3 µm. Pycnidiosporae (phialosporae) sphaeroideae, pallide brunneae, verruculosae, 3-4 x 2-3.5 µm

In the course of examination of the surface features of spores of Coniothyrium species by electron microscopy, an undescribed species was reported to having an uneven surface similar to C. minitans Campbell (1947) and C. sarcinellae Sahni (1968) by Punithalingam & Jones (1970). Since a Coniothyrium species that combines all the characters of the unnamed species has apparently not been recorded before, it is here described as new.
The species described here is readily distinguished from all other Coniothyrium species having roughened surfaces on examination by optical microscopy, by its rather smaller spores. The spore dimensions of Coniothyrium species having an uneven spore surface so far described are as follows: C. onychiuri Punithalingam 3-4. x 2-3.5 µm; C. minitans Campbell 4-6 x 3-5.5 µm, C. sarcinellae Sahni 8-10 x (4-) 5-6 (-7) µm.

Ex Onychiuro psuedofimetario, Auckland, New Zealand, Mrs J. Young, 1969, IMI 137464 typus.