Ephemera (Sinephemera) obliqua, Lei & Zhou, 2024

Lei, Zhi-Ming & Zhou, Chang-Fa, 2024, The subgenus Sinephemera Kluge, 2004 in China (Ephemeroptera: Ephemeridae: Ephemera Linnaeus, 1758), Zootaxa 5517 (1), pp. 1-68 : 25-31

publication ID	https://doi.org/ 10.11646/zootaxa.5517.1.1
publication LSID	lsid:zoobank.org:pub:B73493AB-2F80-43B2-9396-218EC54A0472
DOI	https://doi.org/10.5281/zenodo.13915339
persistent identifier	https://treatment.plazi.org/id/C513C56F-0501-C109-FF11-F9ACF6F3FE3A
treatment provided by	Plazi
scientific name	Ephemera (Sinephemera) obliqua
status	sp. nov.

Treatment

Ephemera (Sinephemera) obliqua sp. nov. ( Figs 21–26 View FIGURE 21 View FIGURE 22 View FIGURE 23 View FIGURE 24 View FIGURE 25 View FIGURE 26 , 64 View FIGURE 64 )

Description

Mature nymph: Body length 16.0–17.0 mm, caudal filaments 5.0–6.0 mm, antennae 4.0 mm ( Fig. 21 View FIGURE 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 View FIGURE 22 ). 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 View FIGURE 21 , 22A View FIGURE 22 ). Area between ocelli black ( Fig. 22A View FIGURE 22 ). In dorsal view, two mandibular tusks subequal in length, slightly shorter than head ( Figs 21A, C View FIGURE 21 , 22A View FIGURE 22 ). Mouthparts ( Fig. 23 View FIGURE 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 View FIGURE 23 ). Pronotum with pair of black stripes ( Fig. 22A View FIGURE 22 ). Tergites I–II with produced median ridge on posterior margin, ridge of tergite II produced into spur or spine ( Fig. 22B View FIGURE 22 ). 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 View FIGURE 21 ). Sternites II–IX with pair of oblique stripes, those of segment IX sometimes straight ( Figs 21B, D View FIGURE 21 ).

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 View FIGURE 24 ). A 1 of forewing with 10 veinlets ( Fig. 25B View FIGURE 25 ). Tergite II with median produced spur on posterior margin ( Fig. 25D View FIGURE 25 ). 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 View FIGURE 24 ); lateral margins of tergites VII–IX or VIII–IX black ( Fig. 24A View FIGURE 24 ). Sternites I–IX with pair of oblique stripes ( Fig. 24C View FIGURE 24 ).

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 View FIGURE 25 ). 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 View FIGURE 25 ); apices of penes slightly expanded ( Fig. 25G View FIGURE 25 ).

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 View FIGURE 24 ). Spine of tergite II shorter than in males ( Fig. 25C View FIGURE 25 ). Crossveins of stigma of forewings without branch or only with one to few branched ( Fig. 25A View FIGURE 25 ); hindwings with pigmented veins and outer margin, pigments on hindwing margin much narrower than in male, sometimes indistinct to invisible ( Fig. 25E View FIGURE 25 ). Legs pale, foretibiae and foretarsi blackened ( Figs 24D–F View FIGURE 24 ).

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 View FIGURE 26 ). Legs pale except foretibiae brown and foretarsi grey. Pronotum and mesonotum with pair of black stripes ( Fig. 26A View FIGURE 26 ). Forewings with median transverse band, crossveins of stigmatic area anastomosed ( Fig. 26B View FIGURE 26 ). Hindwings with pigmented outer margins ( Fig. 26C View FIGURE 26 ). Tergites I–II with posteromedian ridge, second one larger than first one but shorter than in male ( Fig. 26D View FIGURE 26 ).

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 View FIGURE 22 ). (2) Both tergites and sternites II–IX with a pair of oblique stripes, tergites VI–X with two pairs of median stripes ( Fig. 21 View FIGURE 21 ). In addition, its relatively short mandibular tusks and frons are good identification characters ( Figs 21 View FIGURE 21 , 22A View FIGURE 22 ). Male imagine: Like in the nymph, the spines of tergite II is a perfect feature of this species ( Fig. 25D View FIGURE 25 ). In addition, its black head and thorax, reddish abdomen, stripe pattern are useful characters ( Figs 24A–C View FIGURE 24 ). Its black forceps and separated penes are also somewhat unique in the genus ( Figs 25F–G View FIGURE 25 ).

Female imagine: Besides the color pattern of abdomen ( Figs 24D–F View FIGURE 24 ), tergites II has a median spine ( Fig. 25C View FIGURE 25 ), hindwings have pigments on outer margin ( Fig. 25E View FIGURE 25 ).

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 View FIGURE 25 ) is larger than that of E. pictiventris ( Fig. 37D View FIGURE 37 ); (2) the penes of E. pictiventris is slenderer than this species, the penial apex of E. pictiventris is acute ( Figs 37H–I View FIGURE 37 ) but the penes of E. obliqua sp. nov. are slightly expanded ( Figs 25F–G View FIGURE 25 ); (3) lateral margins of tergites VII–IX have black stripes ( Figs 24A, D View FIGURE 24 , 26A View FIGURE 26 ), which are absent in E. pictiventris ; (4) tergites VI–X or V–X have median stripes ( Fig. 24 View FIGURE 24 ), but those similar stripes only present on tergites VII–X of E. pictiventris ( Fig. 36 View FIGURE 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 GoogleMaps ; 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 View FIGURE 64 ): Central to northeastern China (Hubei, Liaolin).