Ephemera (Sinephemera) obliqua Lei & Zhou, 2024, sp. nov.
Creators: name: Lei, Zhi-Ming
name: Zhou, Chang-Fa
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Ephemeroptera
Ephemeridae
Ephemera
Ephemera obliqua

description: Ephemera (Sinephemera) obliqua sp. nov. (Figs 21–26, 64)
Description
Mature nymph: Body length 16.0–17.0 mm, caudal filaments 5.0–6.0 mm, antennae 4.0 mm (Fig. 21). Scape and pedicel of antennae covered with dense golden hair-like setae, those of pedicel longer; articulations of flagella with setal rings (Fig. 22A). Frons with subequal length and width, lateral margins straight, anterior margin deeply forked, margins and dorsal surface with golden hair-like setae (Figs 21A, C, 22A). Area between ocelli black (Fig. 22A). In dorsal view, two mandibular tusks subequal in length, slightly shorter than head (Figs 21A, C, 22A). Mouthparts (Fig. 23): maxillary and labial palpi with three segments, segment II of maxillary palp slightly shorter than segment I or III, latter two subequal in length (Figs 23B, F). Pronotum with pair of black stripes (Fig. 22A). Tergites I–II with produced median ridge on posterior margin, ridge of tergite II produced into spur or spine (Fig. 22B). Tergites I–IX with pair of oblique black stripes, tergites VI–X with two additional pairs of median stripes but those of segment VI–VII sometimes indistinct, one additional pair of straight stripes nearby lateral margins on tergites VIII–IX (Figs 21A, C). Sternites II–IX with pair of oblique stripes, those of segment IX sometimes straight (Figs 21B, D).
Male imagine (forelegs and wings broken): Body length 17.0–18.0 mm; head and thorax chocolate black but abdomen reddish brown (Figs 24A–C). A 1 of forewing with 10 veinlets (Fig. 25B). Tergite II with median produced spur on posterior margin (Fig. 25D). Tergites I–IX with pair of reddish black oblique stripes, midline of them pale; pair of additional pale stripes on tergites V–X or VI–X, this making tergites V–X or VI–X with two additional pairs of reddish to brown stripes (Fig. 24B); lateral margins of tergites VII–IX or VIII–IX black (Fig. 24A). Sternites I–IX with pair of oblique stripes (Fig. 24C).
Genitalia: Styliger plate slightly extended posteriorly into quadrate lobe, its posterior margin concave, with pair of transverse black stripes nearby forceps. Forceps black except apical segment. Segments III–IV relatively short, combined length of them ca. 1/3–1/4 segment II (Fig. 25F). Penes slender, separated but space beteen them less than width of penis, apical 1/4 slightly bent outwards, lateral half of them sclerotized, grey, inner half pale (Fig. 25F); apices of penes slightly expanded (Fig. 25G).
Female imagine: Body length 18.0–23.0 mm, forewing 18.0–23.0 mm, hindwings 8.0–9.0 mm, cerci 20.0–23.0 mm, terminal filament 18.0–20.0 mm. Body general pale, with similar reddish to brown stripes as male but much clearer (Figs 24D–F). Spine of tergite II shorter than in males (Fig. 25C). Crossveins of stigma of forewings without branch or only with one to few branched (Fig. 25A); hindwings with pigmented veins and outer margin, pigments on hindwing margin much narrower than in male, sometimes indistinct to invisible (Fig. 25E). Legs pale, foretibiae and foretarsi blackened (Figs 24D–F).
Male subimagine: Body length 17.0 mm, cerci 15.0 mm, paracercus 13.0 mm, forewing 15.5 mm, hindwing 5.5 mm. Body color pattern and structures similar to male but much paler (Fig. 26A). Legs pale except foretibiae brown and foretarsi grey. Pronotum and mesonotum with pair of black stripes (Fig. 26A). Forewings with median transverse band, crossveins of stigmatic area anastomosed (Fig. 26B). Hindwings with pigmented outer margins (Fig. 26C). Tergites I–II with posteromedian ridge, second one larger than first one but shorter than in male (Fig. 26D).
Female subimagine: Body length 23.0 mm, cerci 16.0 mm, forewing 22.0 mm, hindwing 8.0 mm. Similar to male subimagine but slightly duller.
Diagnosis: Nymph: (1) This species can be identified by its unique spines or spurs on tergites I–II (Fig. 22B). (2) Both tergites and sternites II–IX with a pair of oblique stripes, tergites VI–X with two pairs of median stripes (Fig. 21). In addition, its relatively short mandibular tusks and frons are good identification characters (Figs 21, 22A). Male imagine: Like in the nymph, the spines of tergite II is a perfect feature of this species (Fig. 25D). In addition, its black head and thorax, reddish abdomen, stripe pattern are useful characters (Figs 24A–C). Its black forceps and separated penes are also somewhat unique in the genus (Figs 25F–G).
Female imagine: Besides the color pattern of abdomen (Figs 24D–F), tergites II has a median spine (Fig. 25C), hindwings have pigments on outer margin (Fig. 25E).
Comparison: This species is very similar to E. pictiventris in the color pattern and male genitalia shape. However, the males of them can be separated by at least four characters: (1) The median spine on tergites II or I–II of this species (Fig. 25D) is larger than that of E. pictiventris (Fig. 37D); (2) the penes of E. pictiventris is slenderer than this species, the penial apex of E. pictiventris is acute (Figs 37H–I) but the penes of E. obliqua sp. nov. are slightly expanded (Figs 25F–G); (3) lateral margins of tergites VII–IX have black stripes (Figs 24A, D, 26A), which are absent in E. pictiventris; (4) tergites VI–X or V–X have median stripes (Fig. 24), but those similar stripes only present on tergites VII–X of E. pictiventris (Fig. 36). In addition, this species distributes in central to northeastern China, while E. pictiventris is known from western China (Fig. 65).
Etymology: from the Latin word “ obliqua ” (femenine, nominative case), meaning oblique, indicating the pattern of stripes in tergites and sternites.
Material: China: holotype (♂ imagine), Xiao-Shen-Long-Jia (31.307235°N, 110.361455°E), Badong county, Hubei province, leg. De-Wun Gong, 2023-VI-18–20; paratypes: 1 ♂ and 5 ♀ imagines,, same as the holotype; other materials: 2 ♂ subimagines, Jiu-Hu-Ping, Shen-Long-Jia, 2023-VI-25, others same as the former; 8 ♀ imagines, Monkey center, 2023-VI-12–14, others same as the former; 1 ♀ imagine and 2 ♀ subimagines, 7 nymphs, Fu-Lu village, Mu-Yu town, 2023-VI-15–16, others same as the former; 6 ♀ imagines, Wa-Er-Huang valley, Qingshui county, Shanxi province, leg. Xin-He Qiang, 2022-VIII-26; 1 ♂ imagine, Baiyun Mt., Songsan county, Henan province, leg. Peng Li & Wei-Xing Liu, 2004- VII- 14–18.
Distribution (Fig. 64): Central to northeastern China (Hubei, Liaolin).
description: Published as part of Lei, Zhi-Ming & Zhou, Chang-Fa, 2024, The subgenus Sinephemera Kluge, 2004 in China (Ephemeroptera: Ephemeridae: Ephemera Linnaeus, 1758), pp. 1-68 in Zootaxa 5517 (1) on pages 25-31, DOI: 10.11646/zootaxa.5517.1.1, http://zenodo.org/record/13915182