With reference to D.alnea, which was described from the same host genus, Alnus.

Conidiomata pycnidial, discoid, immersed in bark, scattered, erumpent through the bark surface, with a solitary locule. Locule 800–1250 μm diam., undivided. Conidiophores 22–68.5 × 1.5–3 μm (av. = 39.8 × 2.2 μm, n = 50), cylindrical, attenuate towards the apex, hyaline, slightly brown at base, phialidic, unbranched, straight or slightly curved. Alpha conidia (5.8–)7.1–8.9(–11.2) × (1.5–)1.8–2.2(–2.7) μm (av. = 7.9 × 2.0 μm, n = 50), L/W = 3.2–4.7 (av. = 3.8, n = 50), hyaline, aseptate, subcylindrical with a nearly rounded apex, multi-guttulate, sometimes acute at both ends. Beta conidia not observed.

Colonies are initially white with fluffy aerial mycelium, becoming dirty white after 2 weeks, and conidiomata are randomly distributed with orange conidial drops oozing out of the ostioles.

NETHERLANDS. Utrecht City, on branches of Alnusglutinosa, 5°11’32” E, 52°05’22” N, 8 Apr. 2019, N. Jiang (holotype CAF800005 = JNH0001; ex-type living culture: CFCC 54190; other living culture: M2A).

Diaporthenivosa and D.alnea were recorded from the host genus Alnus. Udayanga et al. (2014) investigated the lectotype of Diaporthenivosa and revealed it as a Melanconis species based on a well-developed ectostromata and the ascospores characteristics, and Jaklitsch and Voglmayr (2020) treated it as a synonym of Melanconismarginalisssp.marginalis. D.alnea has been reported from the Czech Republic, Germany, the Netherlands and the USA, and both sexual and asexual morphs have been described (Udayanga et al. 2014). However, applying the GCPSR principle, D.alnea has recently been considered to be a synonym of Diaportheeres (Hilário et al. 2021), which has also been confirmed in our analyses where the ex-epitype isolate CBS 146.46 of D.alnea is placed within the D.eres clade (Fig. 1). Diaporthepseudoalnea morphologically differs from D.alnea (now D.eres) by its longer conidiophores (22–68.5 × 1.5–3 μm in D.pseudoalnea vs. 9–16 × 1–2 μm in D.alnea; Udayanga et al. 2014). In our multi-gene analyses, D.pseudoalnea forms a distinct phylogenetic lineage which is placed remotely from the isolate CBS 146.46 of D.alnea (Fig. 1).