Bull. Natl. Mus. Nat. Sci., Ser. B, 45(2), pp. 57–62, May 22, 2019

Survey of Stream Spora in Maliau River in Borneo
Tsuyoshi Hosoya1,*, Hirokazu Tsukaya2,3 and Monica Suleiman4
1

Department of Botany, National Museum of Nature and Science,4–1–1 Amakubo, Tsukuba, Ibaraki 305–0005, Japan2
Department of Biological Sciences, Faculty of Science, The University of Tokyo,
7–3–1 Hongo, Bunkyo-ku, Tokyo 113–0033, Japan
3
Bio-Next Project, Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences,Yamate Build. #3, 5–1, Higashiyama, Myodaiji, Okazaki, Aichi 444–8787, Japan4
Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah,Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia* E-mail: hosoya@kahaku.go.jp(Received 26 January 2019; accepted 27 March 2019)

Abstract Stream spora collected from Maliau River in Borneo Island were recorded with illustrations. Fourteen species among 11 genera and eight unidentiﬁed taxa were recognized.
Key words : freshwater hyphomycetes, fungal biodiversity, Ingoldian fungi, Malaysia, streamspora.

Introduction
Fungal diversity in tropical areas where enormous biodiversity is known, is one of the fascinating topics in mycology. Much attention has
been paid to accumulate data on local mycobiota
in Southeast Asia, where the fungal inventory is
still insufﬁcient (Watling et al., 2002a, 2002b).
Aquatic hyphomycetes are a remarkable groupof fungi that are characterized by tetra-radiatingor coiled conidial morphology, which is considered to be an adaptation to aquatic habitats. Mostof this group of fungi are also known as “Ingoldian fungi” or “freshwater hyphomycetes”. The
morphological adaptation of conidia results intheir accumulation in water foams, which allows
for convenient and easy sampling.
As a part of the elucidation of mega diversityof fungi in Malaysia, aquatic hyphomycetes wereenthusiastically studied (e.g. Nawawi, 1985;
Goh, 1997; Marvanová, 1997; Graça et al.,2016). There are still a number of unidentiﬁed
species (Nawawi, 1985), but less attention has
been paid partially due to the low number of

mycologists in the country (Bärlocher, 2016).
The Maliau Basin Conservation Area (MBCA)
comprises tremendous biodiversity, for example＞1,010 tree species and ＞86 mammal species(http://maliaubasin.org/research/). However, despiteextensive biodiversity research, so far intensive
mycological studies have not been carried out(Yayasan Sabah, 2014). In 2017, with permission
from both the Maliau Basin Management Committee [YS/MBMC/2016/184 (to HT)] and theSabah Biodiversity Council [JKM/MBS.10002/2 JLD.5(23) (to HT)], HT and MS participatedin a botanical survey at the Maliau Basin Conservation Area (Sabah, Borneo, Malaysia), which
covers ca. 59,000 ha and is surrounded by sandstone ridges. During the expedition, HT collectedwater foam samples in Maliau River.
The Maliau River is characterized by its teacolor water and is well-known for its foaming
nature (Harun et al., 2010), probably due to thesaponin and humic composition originated frompeat from the river basin. For the further elucidation of the local mycobiota in Borneo Island, apreliminary observation on the spore diversity inTsuyoshi Hosoya et al.

58

the ﬁxed water foam samples are presented in thepresent paper.
Materials and Methods
Water foam samples were collected beside theriver bank of the Maliau River along Seraya
Trail, Maliau Basin, Sabah, Borneo, Malaysia(＋4.7425, ＋116.9638, Fig. 1) on August 29,Fig. 1. Map of Borneo Island and collection sites.
The mid line shows the equator. Dotted line
shows the boundary of Indonesia and Brunei.

2017. The foam samples were scooped up by aspoon and collected in a 15 ml plastic container,
and ﬁxed with alcohol immediately after collection (Fig. 2). The sample was kept in room temperature until observation. Due to the lack ofappropriate facilities, isolation was not attemptedin this study.
Part of the sample was transferred to a 1.5 ml
Eppendorf tube and centrifuged (5000 g, 30 sec) toobtain concentrated sediment. A drop of the sediment was placed on a slide glass using a Pasteur
pipet, and scanned by light microscopy using an
Olympus BX51 microscope for fungal spores.
Because of the three dimensional morphologyof the conidia, adjusting focus in a single frame in
the photograph was difﬁcult. Hence, digital photographs were taken using Nikon Digital Sight
DS-Fi2 camera system and depth synthesis of thephotographs was processed by Combine ZP software (http://www.hadleyweb.pwp.blueyonder.co.
uk). Line drawings were prepared to support photographic data and drawn using the Olympus
BX-51 microscope equipped with U-DA drawing
tubes and 40× or 100× objective lens.
Results and Discussion
The observed and identiﬁed spores are listed

Fig. 2. Collecting the sample. A. Water foam produced and accumulated along the river bank. B. Close up of thewater foam. Note the tea-colored foam due to the colored water.

Stream spora in Maliau RiverTable 1.

59

List of species obtained in the present study with the comparisons with previous studies
Present study

Alatospora sp.
Anguillospora sp.
Campylospora chaetocladia Ranzoni
Clavatospora ﬁliformis (Nawawi) Marvanová
Condylospora gigantea Nawawi & Kuthub.
Ingoldiella ﬁbulata Nawawi
Ingoldiella hamata D.E. Shaw
Nawawia ﬁliformis (Nawawi) Marvanová
Scutisporus brunneus K. Ando & Tubaki
Subulispora malaysiana Nawawi & Kuthub.
Tricladium brunneum Nawawi
Tridentaria sp.
Triscelophorus acuminatus Nawawi
Triscelosporium verrucosum Nawawi & Kuthub.
Wiesneriomyces javanicus Koord.
Unknown-Nawawi (1985) #75
unidentiﬁed (Fig. 4F)
unidentiﬁed (Fig. 3U)
unidentiﬁed (Fig. 3W)
unidentiﬁed (Fig. 3X)
unidentiﬁed (Fig. 3Y)

Nawawi (1985)

Hosoya et al. (2006)−＋＋−−−＋＋＋＋＋＋＋＋−−＋＋−＋＋−−＋−−−＋

Nawawi (1985) includes two sites (Gambak and Cameron Highlands). Hosoya et al. (2006) includes four sites (TikiKerawang Waterfall, Penang Island, Bukit Gatang, and two sites in Bukit Larut). ＋ shows that the given species islisted in the literature, while — shows not listed. No marks shows that the given species is not compared for its uncertainty in morphological character. Clavatospora ﬁliformis was cited as Nawawia ﬁliformis in Hosoya et al. (2006).

in Table 1, with representatives shown in Figs. 3and 4. In total, 15 species from 14 genera and six
unidentiﬁed taxa (one of which have been repeatedly collected, but no names has been given;
Nawawi, 1985) were recognized.
The sediment contained a number of small particles of insect bodies, plant debris and amorphousmatter that caught stream spora (Fig. 3A–C).
Some debris were accompanied with conidia produced by terrestrial fungi (e.g. Beltrania, Fusarium and Pestalotiopsis; Fig. 3F–I), suggesting
active decomposition of these particles by hyphomycetes caught in stable bubbles. Frequent observation of conidiophores (Fig. 3E) also suggested
higher ability of the foam to capture particles.
With the comparisons of the stream spora in
the temperate zone (Miura, 1974; Ingold, 1975;
Gulis et al., 2005), we observed several interesting trends as follows. Larger spores occurred
more frequently than in temperate zone. Coiled
spores were more frequently observed. Coiled
spores are known as an adaptation to intermediate environments between terrestrial and sub-merged areas (Michaelides and Kendrick, 1982).
On the other hand, tetra-radiating spores wereobserved less frequently. A number of coiled
spores are known in terrestrial fungi living in a
wet environment (e.g. aero-aquatic fungi). Thistendency agreed with the stream mycobiota in
Kita-Iwojima Island (Hosoya et al., 2018).
More dematiaceous spores were observed thanin temperate zone. Dark-colored or melanised
cells are known to be an adaptation to stronger
sunlight intensity, and are a common character intropical micro fungi.
Some spores were found to be germinated. In
aquatic hyphomycetes, germination usually does
not occur in lotic water, but in lentic water. Theseobservation also suggest long-lasting bubbles
provide stable habitat.
In the previous study, basidiomycetous anamorphs, relatively common in the tropics(Nawawi, 1973), were not observed (Hosoya etal., 2006), but Ingoldiella ﬁbulata and I. hamata
were observed in the present study. Although theoccurrence may be affected by seasonality andTsuyoshi Hosoya et al.

60Fig. 3. Materials observed in water foam and some representatives of the stream spora. A. Part of the insect bodyobserved in the foam sample. B. Residue of molted exoskeleton. C. Amorphous material capturing ﬁlamentous
fungal spore. D. Aspergillus conidiophore producing conidia from plant debris captured in the foam. E. Conidiophore of a dematiaceous hyphomycete. F. Pseudospiropes sp. G. Damaged conidia of Beltrania sp. withoutappendages. H. Pestalotiopsis sp. I. Wiesneriomyces javanicus. J. Tricladium brunneum. K. Campylospora
chaetocladia L. Alatospora sp. M. Triscelosporium verrucosum. N. Triscelophorus acuminatus. O. Ingoldiellahamata. P. Close up of conidia of Ingoldiella hamata bearing clamp connections at the septa. Q. Condylopspora gigantea. R. Scutisporus brunneus. S. Nawawia ﬁliformis [Unknown #71 of Nawawi (1985)]. T. Clavatospora ﬁliformis. U. unidentiﬁed. V. Tricladium brunneum. W. unidentiﬁed coiled spore with two dimensional structure. X. unidentiﬁed coiled spore with three dimensional structure. G–L, R, X, depth synthesized.
Scales. A–C, 100 μm. D–Y, 10 μm.

occasion, the comparison with the previous study
shows that Clavatospora ﬁliformis (Nawawi)
Marvanová and Tricladium brunneum are themost widely distributed species in Malaysia.

Acknowledgments
The authors express their gratitude for the permission to the Maliau Basin Management Com-Stream spora in Maliau River61Fig. 4. Representatives of stream spora illustrated by line drawings. A. Condylospora gigantea. B. Tridentaria
sp. C. Nawawia ﬁliformis [Unknown #71 of Nawawi (1985)]. D. Clavatospora ﬁliformis. E. Anguillospora sp.
F. unidentiﬁed. G. Pestalotiopsis sp. H. Ingoldiella ﬁbulata. I. Tricladium brunneum (?). J. Triscelosporium
verrucosum. K. Triscelophorus acuminatus. L. Scutisporus brunneus. M. Wiesneriomyces javanicus. N.
Unknown–Nawawi (1985) #75. similar to Diplocladiella scalaroides G. Arnaud ex M.B. Ellis, but differs inhaving third branch with appendage. O. Triscelophorus acuminatus

mittee [YS/MBMC/2016/184 (to HT)], YayasanSabah (Maliau Basin Conservation Area), andthe Sabah Biodiversity Council [JKM/MBS.
1000-2/2 JLD.5 (23) (to HT)] for the present
study. We also express our thanks to Dr. Joey
Tanney, Paciﬁc Forestry Centre, Canadian Forest
Service, Natural Resources Canada for criticallyreviewing the manuscript.

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