China, Hainan Province, Haikou City: East Harbour National Nature Reserve, on diseased leaves of Ilexchinensis. 23 May 2021, Z.X. Zhang (holotype HSAUP212271; ex-type living culture SAUCC212271).

Named after the host location, Haikou City.

Leaf spots irregular, grey white in centre, brown to tan at margin. Sexual morph not observed. Asexual morph on PDA: Conidiomata globose to clavate, solitary or confluent, embedded or semi-immersed to erumpent, dark brown, exuding globose, dark brown to black conidial masses. Conidiophores indistinct, often reduced to conidiogenous cells. Conidiogenous cells discrete, subcylindrical to ampulliform, hyaline, 5.0–10.0 × 2.0–6.0 μm, apex 1.0–2.0 μm diam. Conidia fusoid, ellipsoid, straight to slightly curved, 4-septate, 16.0–22.0 × 4.5–7.0 μm, mean ± SD = 20.0 ± 1.8 × 5.5 ± 0.4 μm; basal cell conical with a truncate base, hyaline, rugose and thin-walled, 3.0–4.5 μm long; three median cells doliiform, 11.5–15.0 μm long, mean ± SD = 13.2 ± 1.0 μm, wall rugose, septa darker than the rest of the cell, second cell from the base pale brown, 3.5–5.5 μm long; third cell honey-brown, 4.0–6.0 μm long; fourth cell brown, 3.8–5.7 μm long; apical cell 2.5–5.5 μm long, hyaline, cylindrical to subcylindrical, thin- and smooth-walled; with 2–3 tubular apical appendages (mostly 3), arising from the apical crest, unbranched, filiform, 13.5–24.0 μm long, mean ± SD = 19.1 ± 3.5 μm; basal appendage 2.0–7.0 μm long, single, tubular, unbranched, centric.

Colonies on PDA occupying an entire 90 mm petri dish in 7 days at 25 °C in darkness, growth rate of 7.0–14.0 mm/day, edge undulate, white to grey white, with moderate aerial mycelium on the surface, with black, gregarious conidiomata; reverse similar in colour.

China, Hainan Province: East Harbour National Nature Reserve, 23 May 2021, Z.X. Zhang. On diseased leaves of Ilexchinensis, paratype HSAUP212272, living culture SAUCC212272.

Phylogenetic analysis of a combined three-gene ITS-tub2-tef1 showed that Neopestalotiopsishaikouensis formed an independent clade with full-supported (BI/ML = 1/100, Fig. 1) and is phylogenetically distinct from N.cocoes (MFLUCC 15-0152), N.formicidarum (CBS 362.72) and N.sichuanensis (CFCC 54338). Neopestalotiopsishaikouensis can be distinguished from the phylogenetically most closely related species N.cocoes by narrower conidia (4.5–7.0 vs. 7.5–9.5 μm), N.formicidarum by smaller conidia (16.0–22.0 × 4.5–7.0 vs. 20.0–29.0 × 7.5–9.5 μm), and N.sichuanensis by shorter conidia (16.0–22.0 vs. 23.2–32.8 μm). Furthermore, some species were reported from the same host genus Ilex, including Pestalotianeglecta, Pestalotiopsisannulata, P.humicola and P.ilicis. After comparison, P.humicola was closest to N.haikouensis in morphology, but with 78/588 differences in the ITS region (Maharachch. et al. 2014; Liu et al. 2019; Jiang et al. 2021b).