taxonID	type	description	language	source
03F11E5DEC2CFFBAFF34FC97730EFBAD.taxon	etymology	Etymology: Rivulatus is derived from the Latin, rivulus, meaning a small stream or rivulet. Sexual morph: Ascomata perithecial, black, globose to ellipsoid, immersed, semi-immersed, or superficial, scattered, rarely lying horizontally on the substrate. Ascomatal wall black, carbonaceous, textura angularis. Neck black to dark brown, textura epidermoidea, conical, setae absent, periphyses present. Hamathecium of wide, septate paraphyses. Asci cylindrical, stipitate, unitunicate, 8 - spored, with a wide wedge-shaped inamyloid apical ring. Ascospores hyaline, ellipsoid, aseptate, without sheaths or appendages. Asexual morph: Unknown.	en	Fryar, Sally C., Catcheside, David E. A. (2025): A new family of freshwater ascomycetes from Australia: Rivulataceae fam. nov., Rivulatus australiensis gen. et. sp. nov. (Diaporthomycetidae). Phytotaxa 732 (1): 21-34, DOI: 10.11646/phytotaxa.732.1.2, URL: https://doi.org/10.11646/phytotaxa.732.1.2
03F11E5DEC2CFFBAFF34FC97730EFBAD.taxon	type_taxon	Type species: Rivulatus australiensis Fryar & D. E. A. Catches.	en	Fryar, Sally C., Catcheside, David E. A. (2025): A new family of freshwater ascomycetes from Australia: Rivulataceae fam. nov., Rivulatus australiensis gen. et. sp. nov. (Diaporthomycetidae). Phytotaxa 732 (1): 21-34, DOI: 10.11646/phytotaxa.732.1.2, URL: https://doi.org/10.11646/phytotaxa.732.1.2
03F11E5DEC2CFFB4FF34FBFF73E2FF4D.taxon	etymology	Etymology: the specific epithet, R. australiensis, refers to the country in which this species was found, Australia. Saprobic on decaying submerged wood in a freshwater stream. Sexual morph: Ascomata perithecial 335 – 408 × 252 – 456 µm (x = 372 ± 32 × 325 ± 79 µm), black, globose to ellipsoid, immersed, semi-immersed, or superficial, scattered, rarely lying horizontally on the substrate. Ascomatal wall black, carbonaceous, textura angularis. Neck 240 – 369 × 74 – 156 µm (x = 308 ± 48 × 109 ± 31 µm), black to dark brown with orange hue, textura epidermoidea, conical, setae absent, periphyses up to 30 µm long. Hamathecium composed of septate paraphyses, constricted at the septa, up to 7 µm wide. Asci 85 – 135 × 8 – 13 µm (x = 108 ± 12 × 10 ± 1 µm), cylindrical, stipitate, unitunicate, 8 - spored, with a wide, wedge-shaped, strongly tapered, inamyloid apical ring, 2 – 2.5 µm (x = 2.3 ± 0.3 µm) high, (3.5 –) 4 – 4.5 µm (x = 4.2 ± 0.3 µm) wide. Ascospores (12.5 –) 13 – 16 (– 17) × 5 – 6 (– 7) µm (x = 14.3 ± 1 × 5.6 ± 0.5 µm), hyaline, ellipsoid, aseptate, multiguttulate, without sheaths or appendages. Asexual morph: Unknown. Additional material examined: AUSTRALIA, South Australia, Scott Creek Conservation Park, 254 m, (- 35.09610 ° 138.68310 °), on submerged decaying wood in an ephemeral stream, 26 August 2020, S. C. Fryar, AD 291642, AD 291637, AD 291615, and AD 291617. AD 291637 GenBank numbers: ITS — OQ 799380; 28 S — OQ 799374; 18 S — OQ 799388. Notes: Rivulatus australiensis is most similar to Rubellisphaeria abscondita Réblová & J. Fourn., but the perithecia and necks of Rivulatus australiensis are black, not brown, and the spores do not form a septum (Réblová et al. 2016). There are similarities with some Annulatascus species, such as Annulatascus menglensis D. M. Hu et al. (Hu et al. 2012) and A. velatisporus K. D. Hyde (Hyde 1992) in having aseptate, hyaline spores, but the spores and asci, and ascus apical apparatus of Rivulatus australiensis are significantly smaller. There are also some similarities with Atractospora species, in particular, Atractospora thailandensis W. Dong et al. (Zhang et al. 2017), but the asci and spores of Rivulatus australiensis are smaller. Also, the spores of Atractospora thailandensis are fusiform (compared with the ellipsoid spores of R. australiensis) and have sharply tapered ends. Atractospora ellipsoidea is also similar to Rivulatus australiensis, but has smaller ascomata, has coriaceous rather than carbonaceous ascomatal walls, and the ascospores of Atractospora ellipsoidea are 1 - septate when mature compared with the aseptate ascospores of Rivulatus australiensis (Dong et al. 2021). In addition, the apical apparatus in R. australiensis is wedge-shaped, which is not a feature of Atractospora species (Ho et al. 1999, Réblová et al. 2016, Zhang et al. 2017, Luo et al. 2019, Dong et al. 2021, Zhang et al. 2023).	en	Fryar, Sally C., Catcheside, David E. A. (2025): A new family of freshwater ascomycetes from Australia: Rivulataceae fam. nov., Rivulatus australiensis gen. et. sp. nov. (Diaporthomycetidae). Phytotaxa 732 (1): 21-34, DOI: 10.11646/phytotaxa.732.1.2, URL: https://doi.org/10.11646/phytotaxa.732.1.2
03F11E5DEC2CFFB4FF34FBFF73E2FF4D.taxon	description	Rivulatus australiensis also shares similarities with a species found commonly in streams in Hong Kong, which has not been formally described, ‘ Aquaticola rhomboida’ (Ho 1998). Similarities include ascomata lying horizontally on the host, cylindrical asci, wide septate, tapering paraphyses, and ellipsoid ascospores. However, there are notable differences. Rivulatus australiensis ascomata are larger (335 – 400 × 270 – 370 µm vs 80 – 140 × 160 – 260 µm), black and carbonaceous compared with the dark brown and coriaceous ascomata of ' Aquaticola rhomboida'. The ascospores of Rivulatus australiensis are smaller than those of ‘ Aquaticola rhomboida’ (13 – 16 × 5 – 7 µm vs 16 – 20 (– 22.5) × 7 – 8.5 µm) and the spores of R. australiensis have rounded ends, whereas the spores of ‘ Aquaticola rhomboida’ are acute. In addition, the apical apparatus in ‘ A. rhomboida’ is not wedge-shaped.	en	Fryar, Sally C., Catcheside, David E. A. (2025): A new family of freshwater ascomycetes from Australia: Rivulataceae fam. nov., Rivulatus australiensis gen. et. sp. nov. (Diaporthomycetidae). Phytotaxa 732 (1): 21-34, DOI: 10.11646/phytotaxa.732.1.2, URL: https://doi.org/10.11646/phytotaxa.732.1.2
