Peltocercyon sanaii ( Hoshina, 2008 ), 2025

Mai, Zuqi, Jia, Fenglong, Ryndevich, Sergey K., Angus, Robert, Minoshima, Yûsuke N., Fikáček, Martin & Růžička, Jan, 2025, Taxonomic Revision and Phylogeny of the Genus Peltocercyon d'Orchymont, 1925 (Coleoptera: Hydrophilidae: Megasternini), Zootaxa 5671 (1), pp. 1-74 : 58-59

Peltocercyon sanaii ( Hoshina, 2008) , comb. nov.

Figs 29A–G , 30A–F , 32A, B .

Cercyon sanaii Hoshina, 2008: 2 . Type locality: Japan (Fukui Pref., Honshu )

Type material. Paratypes: 2 spec. ( HHFC): Japan, Honshu, Fukui Pref., Fukui City, Ichijô-daki , 29.vi.2004, H. Hoshina lgt .

Additional material examined. 1 male, 1 female ( KMNH), “Tentaki / Hyogo Pref. / 7.Ⅴ.1997 / H. Hoshina leg. // CERCYON / sanaii / Hoshina, 2008 / Det. H. Hoshina, 2018 ”; 1 male ( KMNH), “Mt. Saragamine / Ehime Pref. / 6.VIII.1998 / H. Hoshina leg. // CERCYON / sanaii / Hoshina, 2008 / Det. H. Hoshina, 2018 ” 1 female ( NMP), “ JAPAN: HONSHU / Osaka-Fu / Minoo City Park, FT / T. Lackner leg, 14.Ⅴ.2007 // CERCYON subopacipennis ?? / S. Ryndevich det. 2012”

Remarks. No detailed description of the metaventrite was provided in the original description of this species, and the drawing provided by Hoshina (2008; fig. 7) seems inaccurate for the structures on the mesoventrite. Based on the examination of photographs of paratypes and actual specimens identified as Cercyon sanaii by H. Hoshina, we found that the species has arcuate ridges on the anterolateral corners of the metaventrite and that they cross the complete femoral lines, indicating that the species belongs to Peltocercyon . Hoshina (2008) compared this species to Cercyon vagus (= Peltocercyon vagus ), indicating that it differs by more opaque elytra, compared to the smooth elytra of Cercyon vagus (in fact, the latter species also has microreticulation on elytra, though it is sparser, resulting in a shinier appearance, see above). Cercyon sanaii was not mentioned by Hoshina (2016) who transferred Cercyon subopacipennis Nakane, 1965 to Peltocercyon , neither in the descriptions of the other new Japanese Peltocercyon species by Hoshina (2018, 2021). When compared with all these species, Peltocercyon sanaii seems very similar to P. ohoni Hoshina, 2021 in both external morphology and male genitalia, and we suspect both names may in fact refer to the same species. However, since we have not studied and compared type specimens of both species, we treat them as separate species here.

Distribution ( Fig. 41 ). Japan (Honshu, Shikoku).

Figures

FIGURE 29. Peltocercyon sanaii (Hoshina, 2008), comb. nov. (specimen from Hyogo, Japan) A–C: habitus. D–G: male genitalia. A: dorsal view. B: lateral view. C: ventral view. D: aedeagus. E: median lobe. F: tegmen, G: sternite 9. Scale bars 0.5 mm.

FIGURE 30. SEM photos of Peltocercyon sanaii (Hoshina, 2008) A: punctation of pronotum. B: punctation of elytral base C: ventral view of head. D: ventral view of prothorax. E: mesoventral plate and metaventrite. F: abdominal ventrites.

FIGURE 32. Type specimens of Cercyon sanaii (Hoshina, 2008) and Peltocercyon subopacipennis (Nakane, 1965). A, B: holotype of Cercyon sanaii. C–E: holotype of Peltocercyon subopacipennis and its labels. F–I: paratype of P. subopacipennis and its labels. A: dorsal view. B: ventral view. C: dorsal view. D: lateral view. E: labels. F: ventral view. G: labels. H: ventral view. I: labels.

FIGURE 41. Distribution map of species in Peltocercyon vagus group.