MINUTISPHAERA (FRESHWATER ASCOMYCETES) IN EASTERN CANADA: NEW RECORDS
Since the genus was first erected, just over 10 years ago (Ferrer et al. 2011), there have been only 6 collections of Minutisphaera species reported from Japan, France and the United States (Mycoportal website, Freshwater Ascomycetes website, Bao et al., 2019). The current article expands the distribution of two species (M. japonica Tanaka et al. (PHOTOS) MICROSCOPIC PHOTOS OF M. JAPONICA: PEI COLLECTIONS. and M. parafimbriatispora Raja et al. (PHOTOS) MICROSCOPIC PHOTOS OF M. PARAFIMBRIATISPORA: PEI COLLECTIONS to include eastern Canada (Quebec, New Brunswick and Prince Edward Island). The former species representing a new record for North America and the latter a new record for Canada. All specimens are housed in the NB Museum.
As freshwater ascomycetes, they are typically found on decaying wood or twigs either submerged or partially submerged in freshwater streams or rivers. All specimens reported here were found in these habitats.
MICROSPHAERIA JAPONICA(PHOTOS) HABITAT OF M. JAPONICA – ISLE DE SOEURS, LE FLEUVE, ST LAWRENCE RIVER, QUEBEC (PHOTOS) HABITAT OF M. JAPONICA – STREAM NEAR BONSHAW (PEI)
COLLECTION NUMBERS AND DATA FOR M. JAPONICA TANAKA ET AL. ALL SPECIMENS ARE HOUSED IN THE NB MUSEUM
AC 748 PEI: Near Glen Afton Hall (N46.09.52 W63.13.47) April 1 2006. Ascomata small black discs on surface, bitunicate asci multiseriate, paraphyses with brown exudate on the surface, spores hyaline eventually brown, 25-30×9-11µm. No additional characters recorded.
AC 918 PEI: Strathgartney Park (N46.12.12 W63.20.32) July 6 2008. Ascospores 28-40×11-15µ, light brown but darker at the apices. Asci 50-80×30µm short stipitate, multiseriate, 8-spored some less than 8, thickened at ascus apex; ascomata turbinate to disc shaped black, paraphyses branched at apex with 3-5 swollen cells and black exudate often at apex. No additional characters recorded.
AC 962 PEI: Creek beside dirt near Bonshaw and Trans Canada Hwy (N46.11.90 W63.20.16) July 27 2008. Cultured, spores germinate at the apex. Young mycelium convoluted on antibiotic media but once started and transferred to V-8 colony shows cinnamon brown colour and normal hyphae; no anamorph after 3 weeks. No additional characters recorded.
AC 1240 PEI : Nine Mile Creek, near Glen Afton Hall (N46.09.52 W63.13.47) Aug 20 2010. Ascomata superficial, disc-shaped, 100µm dia, black with short protruberances around margin; asci 35×10µm, bitunicate; spores hyaline to very pale brown, 2-celled, septum supra median, with many oil globules. No additional characters recorded.
AC 2008 PEI : Creek beside dirt road near Bonshaw and Trans Canada (N46.11.90 W63.20.16) Aug 4 2013. Small black turbinate discs or ascomata with broad ostiole; spores hyaline, brown at maturity, 26-30×10-11µm, uniseptate, septum sometimes slightly submedian. No additional characters recorded.
AC 2521 PEI: Creek beside dirt near Bonshaw and Trans Canada Hwy (N46.11.90 W63.20.16). Aug 31 2021. Ascomata with short dark hyphal protuberances (10×8µm) near ostiole or margin of disc; ascomata appear perithecioid at first then opening with a broad ostiole and appear discomycete-like, 150µm dia and 120µm height, peridium textura angularis; asci clavate (70)80-90×18-22µm; has both brown (mature) and hyaline (immature) spores, spores hyaline when at first in asci and brown when mature (often with darker areas at the apices like germ pores), 25-30×9-11µm; paraphyses filamentous/branched with dark brown exudate at the apices. No additional characters recorded.
AC 2275 QUEBEC: Isle de Soeurs Montreal shore of Fleuve St Laurent, Quebec (N45.46.15 W73.54.64) April 19 2018. Ascomata small with a broad pore at maturity; spores 26-35×10-11µm). No additional characters recorded.
CGAC 134 NEW BRUNSWICK: Caledonia Gorge washed out bridge (N45.79.52 W64.78.52) Aug 13 2012. Ascomata small with a broad pore; spores 28-35×9-11µm. No additional characters recorded.
DISCUSSION MINUTISPHAERA JAPONICA: It should be noted that AC 1582, originally identified as Poetschia cratincola (Rehm) Hafellner and included on the Mycoportal website as such, likely represents Minutisphaera japonica. Before I discovered the literature about Minutisphaera I named the freshwater specimens Poetschia cratincola based on the descriptions of Hafellner (1979).Although a terrestrial species it seemed a good fit for my freshwater collections. In retrospect several early collections labelled Poetschia cratincola probably represent M. japonica.
In my experience M. japonica is often an early colonizer on wood (deciduous twigs) recently fallen into a stream. It also develops quickly on wood that is left to dry. This suggests a start/stop activity, fruiting only when deposited onto a dry stream bed. When washed back into an aquatic environment perhaps it adopts a more vegetative role, fruiting only when exposed and drying.
The suggestion that some Minutisphaera species might survive as endophytes during part of the life cycle (Raja et al. 2015) is interesting. Perhaps fruiting on land allows the spores to be dispersed to suitable terrestrial hosts.(PHOTOS) MICROSCOPIC PHOTOS OF M. JAPONICA: PEI COLLECTIONS. Note dark hyphal appendages near margin of disc (PHOTOS) M. JAPONICA: QUEBEC COLLECTION
MICROSPHAERIA PARAFIMBRIATISPORA(PHOTO) HABITAT OF M. PARAFIMBRIATISPORA – STREAM NEAR LAKE VERDE (PEI)
COLLECTION NUMBERS AND DATA FOR M. cf. PARAFIMBRIATISPORA RAJA ET AL. ALL SPECIMENS ARE HOUSED IN THE NB MUSEUM
AC 2415 PEI: Watervale, Lake Verde (N46.2684 deg W62.89.73deg) Aug 3 2020.; Ascomata small perithecioid with short dark spines (appendages) around ostiole; hyaline spores 21-25×8-10µm brown with age, gel sheath prominent. No additional characters recorded.
AC 2445 PEI: Auburn Demonstration Woodlot (N46.2912 W62.9078 deg) June 30 2020. Ascomata very small (120×100µm), superficial, subglobose, peridium text. angularis, short black hyphal-like protruberances “spines” around ostiole; asci non-stipitate, 50-70×20-25µm, irregularly bi-triseriate, bitunicate; no paraphyses observed; spores obovoid, uniseptate with upper cell shorter and wider than lower cell, hyaline when young in older spores becomes 3-septate and light brown (darkening may be a result of gel sheath congealing on spore surface), 20-24×8-9µm, gel sheath surrounds spore but indented at the septum, thin appendages protruding from septum. No additional characters recorded.
AC 2531 PEI: Watervale Lake Verde, corner of Hwy 5 &213 (N46.2684 deg W62.89.73deg) Sept 15 2021. Ascomata 150µm diameter, perithecial like, broad ostiole with hyphal protruberances; spores 1-septate, many oil globules, 20-26×7-9µm, upper cell shorter and wider than lower cell, with appendages. No additional characters recorded. This is probably a stable colony as a collection was made in 2020 at the same location (see AC 2415).
DISCUSSION MINUTISPHAERA PARAFIMBRIATA: Based on a study by Raja et al. (2015), there may be group of cryptic species nested aroundM. parafimbriatispora. Since no molecular analysis of my collections was performed I prefer to include a cf. designation at this time. In my collections I noticed that the ascomata sometimes developed in a thin layer of algae.(PHOTOS) MICROSCOPIC PHOTOS OF M. PARAFIMBRIATISPORA: PEI COLLECTIONS (note small black hyphal extensions on ascomata and gel sheath around spores)
Bao et al. 2019. Minutisphaera aquaticum sp. nov. increases the known diversity of Minutisphaeriaceae. Asian Journal of Mycology 2: 306-314.
Ferrer et al. 2011. Minutisphaera and Natipusilla: Two new genera of freshwater Dothideomycetes. Mycologia 103: 411-423.
Freshwater Ascomycetes website – http:fungi.life.illinois.edu
Hafellner, J 1979. Karschia. Revision einer Sammelgattung an der Grenze von lichenisierten und nicht-lichenisierten Ascomyceten [Revision of a collective genus on the border of lichenized and non-lichenized Ascomycetes]. Beiheft zur Nova Hedwigia (in German). Vol. 62. pp. 1–248.
Mycoportal website – https://www.mycoportal.org
Raja, H.A. et al. 2013. Freshwater Ascomycetes: Minutisphaera (Dothideomycetes) revisited, including one new species from Japan. Mycologia 105: 959–976. Raja, H.A. et al. 2015. Minutisphaerales (Dothideomycetes, Ascomycota): a new order of freshwater ascomycetes including a new family, Minutisphaeraceae, and two new species from North Carolina, USA.Mycologia 107: 845-862.