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

Ephemera (Sinephemera) rubrogata sp. nov. (Figs 48–53, 64) Description Mature nymph: Body length 16.0–18.0 mm, caudal filaments 6.0–7.0 mm. Body general pale to golden, pronotum and mesonotum with pair of black stripes dorsally, abdomen with pair of red longitudinal stripes nearby lateral margins (Fig. 48A), ventral side of body pale, with reddish stripes on sternites (Fig. 48B). Frons slightly longer than wide, base of frons slightly wider than apex, anterior margin shallowly concave (Fig. 49A). Sometimes with red transverse line between two lateral ocelli (Figs 48, 49A). Mouthparts (Fig. 50): Two mandibular tusks subequal in size, each of them shorter than head length (Figs 48, 49A). Three segments on maxillary and labial palpi, segment II shorter than others (Figs 50C, F). Legs shown in figure 49B–D. Abdominal tergites I–II with median ridge or spine, that of second segment larger than first one, the latter sometimes invisible (Fig. 49G). Tergites I–VI with pair of slightly oblique red stripes, tergites VII–IX with pair of straight red stripes; those stripes close to lateral margins of tergites (Fig. 48A). Sternites VI–IX or VII–IX with pair of oblique red stripes (Fig. 48B). Male imagine: Body length 12.0–13.0 mm, forewing 16.0–17.0 mm, hindwing 5.5–6.0 mm, caudal filaments 30.0–32.0 mm (Fig. 51A). Head and thorax deep chocolate, forelegs black except base of forefemora; mid- and hindlegs pale (Figs 51A, 52B). Abdomen reddish brown, only median portion of each tergite or midline of them slightly lighter (Fig. 52A). Tergites I-X each with one pair of red stripes nearby lateral margins and additional pair of oblique stripes near midline, median pair usually divided into two sections, making them look like four dots or short stripes (Fig. 52A). In most cases lateral stripes almost occupy whole tergites, median pair usually indistinct (Fig. 52A). Tergite X black. Sternites I–IX of abdomen with two pairs of oblique red stripes, lateral pair longer and convergent anteriorly, median pair shorter and usually divided into four dots; those stripes on segments I–II sometimes indistinct (Fig. 52B). Caudal filaments black (Fig. 51A). Wings washed with chocolate; costal, subcostal and R 1 areas reddish, median transverse band reddish (Figs 51A, 53A–B); A 1 with 6–7 veinlets (Figs 53A–B). Hindwings with pigmented outer margin (Figs 51A, 53C). Spines on abdominal tergites I–II indistinct (Fig. 53D). Genitalia: Black. Segments III–IV of forceps relatively short, combined length ca. segment I (Figs 53E–F); styliger plate with a median cleft (Fig. 53E). Penes brown, shorter than segment I of forceps; except base, two penes separated by a space subequal to penis width; apex of penis slightly expanded, whole body of penes sclerotized (Figs 53E–F); each penis with 3–4 tiny spines on mesal apex (Fig. 53G). Female imagine: Body length 16.0–18.0 mm, forewing 18.0–19.0 mm, hindwing 6.5–7.0 mm, caudal filaments 19.0–21.0 mm (Fig. 51B). Body and wing color similar to male but slightly lighter. Head and thorax chocolate to deep brown, with pale sutures; forelegs blackblack except basal half forefemora, mid- and hindlegs pale (Figs 51B, 52D). Whole wings tinged with amber; costal and subcostal areas together with transverse band of forewings reddish, crossveins of stigmatic area anastomosed (Fig. 51B). Hindwings with pigmented outer margin (Fig. 51B). Abdominal tergite II with median spine, very tiny, sometimes absent. Stripes on tergites and sternites similar to those of male but slightly clearer (Figs 51B, 52C–D). Caudal filaments red to brown (Fig. 51B). Male subimagine: similar to male imagine but stripes of abdomen much clearer than in imagine, tergites I–VI with pair of stripes, tergites VII–IX almost totally red to reddish brown; sternites III–IX with pair of oblique stripes. Forewings with clear median band. Female subimagine: Similar to male subimagine but duller, stripes on dorsal abdomen clear. Etymology: The specific name rubrogata (femenine, nominative) is formed by the combination of the Latin word rubro (meaning red) and “ gata” (way, road, path), referring to the red stripes on its abdomen. Diagnosis: In both nymph and adults, this species is characterized by two red nearly straight stripes near lateral margins of abdominal tergites, and red oblique stripes on sternites I–IX (Figs 48, 52). In male and female imagines, whole wings have amber color, and C, Sc and R 1 fields are tinged with reddish (Figs 51–52). In male imagine, the black genitalia, divided styliger plate and short penes are also unique in the genus (Figs 53E–G). Comparison: This species is similar to E. separigata, both have straight lateral stripes on abdominal tergites, spines on tergites I–II, and oblique stripes on sternites I–IX. Ephemera rubrogata sp. nov. differs from E. separigata (between brackets) by the following characters: (1) The oblique stripes on sternites are red (Figs 48, 52) (those of E. separigata are chocolate to deep brown, Fig. 54); (2) wing membrane pigmented (Fig. 51) (mostly hyaline wings except for median pigmented band), (3) forewing pigmented reddish near fore margin (Figs 53A–B) (hyaline); (4) penes shorter than forceps´ segment I (Figs 53E – F) (penes longer than segment I, Fig. 55C); (5) distributed in western China (northeastern China, Korea and Far East of Russia) (Fig. 65). No other species in the genus Ephemera has two nearly straight stripes on the tergites, they are either oblique or more than one pair. Remarks: The reddish body and wings of this species look like a potamanthid. The cleft styliger plate is unique. Material: China: holotype (♂ imagine), Mutuo road 80K point (29.516159 OiN, 95.577556 OiE), Mutuo county, Xizang province, leg. Xu-Hong-Yi Zheng, De-Wun Gong & Zhen-Xin Ma, 2023-VII-9 – 12; 3 ♂ 4 ♀ imagines 5 ♂ 6 ♀ subimagines 3 nymphs, same as the holotype. Distribution (Fig. 64): China (Xizang).