Pleosporales - CBS - KNAW

Fungal Diversity
ascospores were brown with transverse septa and sparse
longitudinal septa.
The ascomata of this species are similar to those found in
Byssosphaeria and Herpotrichia, especially in the paler area
around the ostiole and even in peridial structure and
development under a subiculum. The numerous wide cellular
pseudoparaphyses and cylindrical asci (in Herpotrichia) are
also similar. The main difference of Karstenula from other
two genera are the 3-septate ascospores with rare longitudinal
septa (1-septate in Byssosphaeria and Herpotrichia).
Phylogenetic study
Karstenula forms a robust phylogenetic clade with
Phaeodothis winteri (Niessl) Aptroot, Didymocrea sadasivanii,
Bimuria novae-zelandiae, Montagnula opulenta, Curreya
pityophila (J.C. Schmidt & Kunze) Arx & E. Müll. and
some species of Letendraea and Paraphaeosphaeria (Kodsueb
et al. 2006a; Zhang et al. 2009a). Consequently,
Karstenula might be included in Montagnulaceae.
Concluding remarks
The description of the type of Karstenula here clearly
excludes it from Melanommataceae as it has wide
pseudoparaphyses. But its Montagnulaceae status can only
be confirmed by more phylogenetic work including
sequencing the generic type of Karstenula (K. rhodostoma).
Katumotoa Kaz. Tanaka & Y. Harada, Mycoscience 46:
313 (2005). (Lentitheciaceae)
Generic description
Habitat terrestrial or freshwater, saprobic. Ascomata smallto
medium-sized, scattered or in small groups, immersed to
erumpent, with a central protruding hairy papilla, subglobose.
Peridium thin, comprising several layers of thinwalled
compressed cells. Hamathecium of dense, cellular,
filliform, embedded in mucilage, branching and anastomosing.
Asci 8-spored, bitunicate, fissitunicate, clavate with
short furcate pedicels. Ascospores apiosporous and hyaline
when young, becoming 2-septate with reddish brown
echinate central cell at maturity, with long gelatinous
terminal appendages.
Anamorphs reported for genus: none.
Literature: Tanaka and Harada 2005b; Tanaka et al. 2009;
Zhang et al. 2009a.
Type species
Katumotoa bambusicola Kaz. Tanaka & Y. Harada,
Mycoscience 46: 313 (2005). (Fig. 41)
Some information for the following description is from
Tanaka and Harada (2005).
Ascomata 240–330 μm high×260–420 μm diam.,
scattered or in small groups, immersed, becoming erumpent,
with a slightly protruding papilla covered with brown
hyphae, subglobose (Fig. 41a). Peridium 13–30 μm thick,
composed of a few layers of lightly pigmented, depressed
cells. Hamathecium of dense, long cellular pseudoparaphyses,
1.5–3 μm broad, embedded in mucilage, branching and
anastomosing. Asci 110–160×17.5–24 μm (x ¼ 139 21mm,
n=10), 8-spored, bitunicate, fissitunicate, cylindro-clavate
withashortfurcatepedicelwhichisupto25μm long
(Fig. 41b and d). Ascospores 39–50(−57)×7–10 μm
(x ¼ 45:8 8:2mm, n=10), biseriate, fusoid to narrowly
fusoid with acute ends, usually curved, apiosporus and
hyaline when young, constricted at the primary septum, the
upper cell longer and broader than the lower one, smooth,
surrounded by a bipolar sheath which is up to 15 μm long,
best seen in India ink, senescent ascospores yellowish
brown, 2–4-septate (Fig. 41c).
Anamorph: none reported.
Material examined: JAPAN, Mt. Iwate, near Yakebashiri,
Hirakasa, Nishine, Iwate, on culms of Oryza sativa L., 19
Oct. 2003, K. Tanaka (HHUF 28663, holotype).
Notes
Morphology
Katumotoa was formally established by Tanaka and
Harada (2005b) to accommodate the monotypic species,
K. bambusicola, which is characterized by immersed
ascomata with a thin peridium comprising thin-walled
compressed cells, cellular pseudoparaphyses, cylindroclavate
and fissitunicate asci and fusoid ascospores with
an elongated bipolar mucilaginous sheath. Based on its
immersed ascomata, psuedoparenchymatous peridium
cells and cellular pseudoparaphyses, Katumotoa was
assigned to Phaeosphaeriaceae (Tanaka and Harada
2005b; Tanaka et al. 2009), but this classification has
been shown to be incorrect in subsequent phylogenetic
studies (Tanaka et al. 2009; Zhangetal.2009a).
Phylogenetic study
Phylogenetic analysis based on five genes (LSU, SSU,
RPB1, RPB2 and EF1) indicates that Katumotoa bambusicola
resides in Lentitheciaceae, and this receives high
bootstrap support (Zhang et al. 2009a). In particular, K.
bambusicola forms a robust clade with Ophiosphaerella
sasicola (Nagas. & Y. Otani) Shoemaker & C.E. Babc.,
which has filliform ascospores (Shoemaker and Babcock
1989b).
Concluding remarks
The hyaline, apiosporous ascospores which become
2–4-celled with central reddish brown cells and large