Ephemera (Sinephemera) rubera Lei & Zhou, 2024, sp. nov.

Ephemera (Sinephemera) rubera sp. nov. (Figs 45–47, 64) Nymph (Fig. 45): Body length 18.0 mm, antennae 6.0 mm, cerci 7.0 mm, terminal filament 10.0 mm (Figs 45A–B). Projected frons with very shallow anterior concave margin, lateral margins straight but convergent anteriorly (Figs 45A, C). In dorsal view, mandibular tusks shorter than head (Figs 45A – B). Tergite I with shallow median ridge, with tuft of hair-like setae on it (Fig. 45D); tergites I–VI with two pairs of reddish brown streaks but median pair faint and indistinct, lateral pair distinct; tergites VII–IX with two pairs of reddish brown streaks, much clearer than those of anterior tergites; median pair narrower and fainter than lateral pair, convergent anteriorly to meet in middle; tergite X without clear dots (Fig. 45A); sternites I–X with pair of reddish brown streaks, those of tergites I–VI oblique but those of segment VII–X almost straight (Fig. 45B). Lateral margins of abdomen pigmented with reddish brown. Posterior margins of tergites I–IX reddish brown (Figs 45A – B). Male imagine (Figs 46 – 47): Body length 26.0–28.0 mm, forewing 23.0 mm, hindwing 10.0 mm, caudal filament 45.0 mm. Pronotum with pair of red to purple longitudinal stripes dorsally, all margins of pronotum red to purple (Fig. 46A); coxae of all legs with stripes (Fig. 46B). Forewings and hindwings with striking markings, outer margins of them tinged purple to chocolate; MP 2 unfused with CuA at base (Figs 47A–C). Tergite I has very shallow median ridge, sometimes invisible (Fig. 47D). Color pattern similar to nymphs but much clearer: tergites I–IX with two pairs of longitudinal red to purple stripes, lateral pair wider and blacker than median one, median pair of tergites I–III sometimes indistinct, anterior part of median pair somewhat convergent (Figs 46A–B). All posterior margins of tergites I–IX pigmented by red to purple, those stripes extended to lateral margins of tergites (Figs 46A–B). Tergite X with pair of reddish dots dorsally (Fig. 46A). Sternites I–IX with pair of oblique red stripes, those of tergites VIII–IX nearly straight; posterior margins of sternites pigmented as transverse reddish line (Fig. 46C). Genitalia: Red to purple, apical half of forceps black; combined length of segments III–IV less than half of segment II (Figs 47E); penes situate together (without space between them) longer than basal segment of forceps, sclerotized laterally except apex (Figs 47E–F). Female and male subimagine: unknown. Etymology: from the Latin word “ rubera ” (femenine, nominative case), meaning red or reddish, referring to the color of the wings and body of this species. Diagnosis: This species is remarkably distinguishable because of two points: (1) its two pairs of red stripes on tergites I–IX (Fig. 46), (2) reddish markings of wings (Fig. 47). Besides the abdominal stripes, the nymphal frons of this species has a very shallow anterior concave margin (Figs 45A–C). Comparison: No similar color pattern (two pairs of nearly straight stripes on abdomen, Fig. 46) of this species are found in other Chinese Ephemera. The stripes of other species are either one oblique pair or three straight pairs. Different dots or bands can be found in the wings of Ephemera but no red markings like in this species, especially the hindwings (Figs 47A–C). The penes of this species is similar to those of E. axillaris (Figs 4H–I): penes longer than basal segment of forceps, apex slightly expanded (Figs 47E–F). But this species has much more colorful body and wings than E. axillaris, and the penes are slightly longer. The stripes on abdomen of both are totally different (E. axillaris has three pairs of stripes on tergites III–IX). Remarks: The markings and color pattern on wings of this species are very similar to some Chinese potamanthids or neoephemerids, like Rhoenanthus Eaton, 1881 or Pulchephemera Zhou, 2021 (see Eaton, 1883 – 1888 and Ma & Zhou, 2021). Material: China: holotype (♂ imagine), Wu-Zhi-Shan Mt. park (18.907855°N, 109.679361°E), Hainan province, leg. Xu-Hong-Yi Zheng & Zhi-Teng Chen, 2023-IV-17; Paratypes: 2 ♂ imagines, same as the holotype; 2 ♂ imagines, Leg. Bing Yan, 2107-IV-18, others same as the types; 2 nymphs, Wu-Zhi-Shan Mt., Hainan province, leg. Xu-Hong-Yi Zheng & De-Wun Gong, 2023-XII-10. Distribution (Fig. 64): China (Hainan).