Ephemera (Sinephemera) strigata Eaton, 1892

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 : 58-64

Ephemera (Sinephemera) strigata Eaton, 1892 ( Figs 60–62, 64)

Ephemera strigata Eaton, 1892: 302 (male and female imagines, male subimagine; syntypes from Japan).

Ephemera strigata — Kimmins, 1960: 309 (male imagine) [designation and figure of lectotype]; Kimmins, 1971: 321 (lectotype depository); Tshernova et al., 1986: 105 (key for imagine); You et Gui, 1995: 110 (male imagine); Zhang et al., 1995: 75; Ishiwata, 2001: 58; Quan et al., 2002: 250; Bae and Liu, 1999: 5; Hwang et al., 2008: 164 (list); Zhou, 2013: 187 (list); Zhou et al., 2015: 235 (list); Kawai and Tanida, 2005: 51 (key for imagine). Tshernova, 1973: 332 (mentioned from Amur river, maybe the first record from China). Horasawa 1931: 34 (first description of nymph); Imanishi, 1940: 175 (nymph, Korea).

Ephemera kuwamayai Navás, 1919: 158 (male imagine from Tokyo, Japan) (synonymized by Ishiwata, 2001: 58).

Ephemera iwatensis Matsumura, 1931: 1467 (female imagine) (synonymized by Ishiwata, 2001: 58).

Ephemera jezonica Matsumura, 1931: 1467 (male and female imagine) (synonymized by Ishiwata, 2001: 58).

Ephemera (Sinephemera) strigata — Kluge, 2004: 235 (subgeneric combination).

Description (see Eaton, 1892 and Kluge, 2004).

Diagnosis: Nymph: two mandibular tusks subequal in length ( Figs 60, 61A); length and width of frons subequal, or slightly longer than wide, lateral margins of frons straight; two projections of frons slightly convergent, or straight, or divergent ( Fig. 61A); three ocelli connected by black stripes ( Figs 60A, C, 61A). Gills I, VI and VII located at middle of lateral margins of tergites, gills II–V at posterolateral angle. Stripe pattern on abdomen: tergites I–IX with pair of oblique stripes enlarged progressively from anterior to posterior and never meet at middle ( Figs 60A, C); sternites II–IX with pair of submedian oblique stripes ( Figs 60B, D); those stripes on segment X indistinct in most cases ( Fig. 60). Margins of tergites and sternites without stripes. Generally looking, abdomen has two markings on each tergite and sternite ( Fig. 60). Tergites I–II have very shallow median ridges ( Fig. 61B).

Male imagine: Tergites and sternites of abdomen have stripes similar to that of nymph. Penes half fused, apical 1/3 slightly divergent, forming V-shaped notch between them; apex of penes slightly sclerotized ( Fig. 62E).

Female imagine: Tergites and sternites of abdomen have stripes similar to that of nymph and male imagine ( Figs 62A–C). Tergites I–II of abdomen with very shallow median ridges ( Fig. 62D).

Comparison: This species can be identified by two independent oblique (sometime triangular) stripes or markings on abdominal tergites ( Figs 60, 62). The male penes are unique in basal half fusing but apical half slightly diverged ( Fig. 62E).

The species E. cornea sp. nov., E. japonica , E. obliqua sp. nov. and E. pictiventris also have two oblique stripes on tergites but they usually have more submedian stripes or pigmented midline on tergites VII–IX at least. The stripes of E. pictiventris are usually longer and slender than those of E. strigata , and their penes are totally different (slender and separated penes in E. pictiventris ).

Remarks: The color pattern of this species is close to E. separigata (see its discussion section). It is suspected that the report of E. separigata in China by Bae and Liu (1999) and Quan et al. (2002) are actual E. strigata because this distribution was not included in the report of Hwang et al. (2008).

Material examined: China: 20 nymphs, Gunan village, Erguna county , Inner Mongolia, leg. Chang-Fa Zhou, Hui Xie & Shi-Lei Wang, 2007-VIII-9 ; 25 nymphs, Genghe river, Genghe city, Inner Mongolia, Hui Xie & Shi-Lei Wang, 2007-VIII-10; 1 ♀ imagine, Mangui town, Genghe city, Inner Mongolia, Hui Xie & Shi-Lei Wang, 2007- VIII-12 ; 3 nymphs, Huma river, Huma county , He-Long-Jiang province, Hui Xie & Shi-Lei Wang, 2007-VIII-17 ; 3 nymphs, Er-Dao-Bai-He town, Fusong county , Jilin Province, leg. Gu Zhao & Shi-Lei Wang, 2008- VII- 24 ; 1 nymph, Song-Jiang-He town, 2008-VII-27 – 28, other information same as the former; 1 nymph, Hunhe river , Liaolin Province, leg. Yuan Zhang & Xing Gao, 2014-IX ; 15 nymphs, Tai-Zi river, others same as the former; 1 nymph, Song-Hua-Jiang river, Manjiang town , Jilin province, Xu-Hong-Li Zheng, 2022-VIII-10 .

The lectotype of this species is deposited in the British Museum ( Kimmins, 1971).

Distribution ( Fig. 64): Northeastern China; Japan, Korea, Mongolia, Russia.

Key to the male imagines of the species in the subgenus Sinephemera

1 Segment I of forceps relatively long, ca. half length of segment II; penes short, only tips of them surpassing styliger plate ( Figs 11E–F, 58G–H, 63C).................................................................................. 2

- Segment I of forceps relatively short, less than 1/4 to 1/3 of the length of segment II; penes long, largely surpassing the styliger plate (as Figs 4H, 42D)................................................................................. 4

2 Most lateral portions of tergites I–IX brown to black ( Figs 9A, 10A–B)...................... Ephemera bistria sp. nov.

- Most lateral portions of tergites I–IX pale to amber, without other pigments (as Figs 56A, 57A–B, 63B)................ 3

3 Tergite I without dot or stripe ( Fig. 57A); distributed in Asia..................................... Ephemera shengmi

- Tergite I with two dots or short stripes ( Fig. 63B); distributed in Europe........................... Ephemera glaucops

4 Styliger plate with a distinct median cleft ( Figs 53E–F)....................................... E. rubrogata sp. nov.

- Styliger plate slightly concave, straight or convex but without clear median cleft (as Figs 17I, 30G).................... 5

5 Tergites VI–IX with brown to black midline (as Fig. 20A)...................................... Ephemera japonica

- Tergites VI–IX with a pair or pairs of submedian stripes but without pigmented midline (as Fig. 24E).................. 6

6 Tergites I–IX with two pairs of red submedian longitudinal stripes ( Fig. 46A); most wings with red markings ( Figs 47A–B)........................................................................................ E. rubera sp. nov.

- Tergites I–IX with oblique markings near lateral margins (as Figs 16A–B); wings with variable markings (as Figs 17D–F)... ................................................................................................... 7

7 Tergites I–II with one pair of oblique stripes, tergites III–IX with three pairs of submedian longitudinal stripes (as Figs 3A, 43A)............................................................................................... 8

- Tergites I–V or I–IX with oblique to straight stripes near lateral margins (as Figs 16A–B)............................ 9

8 Forewings with red dots other than transverse band, hindwings with red median dots or markings ( Fig. 42A, E, F)............................................................................................ Ephemera purpurata

- Forewings with transverse band only, hindwings without dots ( Figs 4A–C).......................... Ephemera axillaris

9 Tergites I–V with oblique stripes near lateral margins ( Fig. 29A)................................ Ephemera pictipennis

- Tergites I–IX with oblique to straight stripes near lateral margins (e.g., Figs 36A, 54A)............................. 10

10 Tergites I–IX with straight stripes near lateral margins (as Fig. 54A)............................. Ephemera separigata

- Tergites I–IX with oblique stripes near lateral margins (as Fig. 36A)............................................ 11

11 Tergites VII–IX with one pair of oblique stripes (as Fig. 36A)................................................. 12

- Tergites VII–IX with three pairs of stripes (as Fig. 16A)...................................................... 13

12 Two penes independent and separated ( Fig. 37H).............................................. Ephemera strigata

- Most parts of two penes closely located ( Fig. 62E)............................................. Ephemera strigata

13 Penes much longer than segment I of forceps ( Figs 17H–J)................................ Ephemera cornea sp. nov.

- Penes slightly longer than segment I of forceps ( Fig. 25F)................................ Ephemera obliqua sp. nov.

Key to the female imagines of the species in the subgenus Sinephemera

1 Tergites VII–IX with brown to black midline ( Fig. 20A)....................................... Ephemera japonica

- Tergites VII–IX with a pair or three pairs of stripes but without pigmented midline................................. 2

2 Sternites I–IX or II–IX with a pair of straight stripes (as Fig. 57D).............................................. 3

- Sternites I–IX or II–IX with a pair of oblique stripes (as Fig. 36D).............................................. 5

3 Stripes on sternites distinct, relatively wide ( Fig. 10D).................................... Ephemera bistria sp. nov.

- Stripes on sternites indistinct, relatively narrow (as Fig. 57D).................................................. 4

4 Tergite I without dot or stripe ( Fig. 57C)..................................................... Ephemera shengmi

- Tergite I with two dots or short stripes (as Fig. 63B)........................................... Ephemera glaucops

5 Tergites I–II with one pair of oblique stripes, tergites III–IX with three pairs of submedian longitudinal stripes (as Fig. 3D).. ................................................................................................... 6

- Tergites I–V or I–IX with stripes but never with three pairs of longitudinal stripes.................................. 7

6 Forewings with red dots other than transverse band, hindwings with red median dots to markings ( Fig. 42B)................................................................................................. Ephemera purpurata

- Forewings with transverse band only, hindwings without dots ( Fig. 2B)............................ Ephemera axillaris

7 Tergites VII–IX with one pair of straight stripes near lateral margins in dorsal view (as Figs 29D, 52C)................. 8

- Tergites VII–IX with one pair or more oblique stripes in dorsal view (as Fig. 24E)................................. 11

8 Whole forewings almost brown to red (as Fig. 51B).......................................................... 9

- Outer half of forewings pigmented brown at most ( Fig. 31D).................................................. 10

9 Wings with several distincgt reddish markings (as Fig. 47A)................................................................................. E. rubera sp. nov. (female unknown, but they are assumed having similar color to males)

- Whole wings tinged with amber ( Fig. 51B).......................................... Ephemera rubrogata sp. nov.

10 Outer half of forewings pigmented brown ( Fig. 31D)......................................... Ephemera pictipennis

- Forewings with median band only........................................................ Ephemera separigata

11 tergites VII–IX with one pair of oblique stripes only (as Fig. 36C).............................................. 12

- Tergites VII–IX with more than one pair of stripes (as Fig. 16D)............................................... 13

12 Wings with dots other than median band..................................................... Ephemera strigata

- Wing without any dot, median band indistinct ( Fig. 35B)..................................... Ephemera pictiventris

13 Lateral margins of tergites I–IX or I–X without pigments ( Fig. 16F)............................... E. cornea sp. nov.

- Lateral margins of tergites VII–IX or VIII–IX black ( Fig. 24D)................................... E. obliqua sp. nov.

Key to the mature nymphs of the species in the subgenus Sinephemera

1 Tergites I–II with one pair of oblique stripes, tergites III–IX with three pairs of submedian longitudinal stripes (as Figs 1A, C) ................................................................................................... 2

- Tergites I–V or I–IX with variable markings but never with three pairs of submedian stripes.......................... 3

2 Two mandibular tusks asymmetrical, left one much longer than right one ( Figs 39, 40A)............. Ephemera purpurata

- Two mandibular tusks almost symmetrical ( Figs 1A–E)......................................... Ephemera axillaris

3 Tergites VII–IX with brown to black midline ( Fig. 19A, C)..................................... Ephemera japonica

- Tergites VII–IX with a pair or pairs of stripes but without pigmented midline...................................... 4

4 Sternites I–IX or II–IX with a pair of straight stripes (as Figs 6B, D)............................................. 5

- Sternites I–IX or II–IX with a pair of oblique stripes (as Figs 60B, D)............................................ 7

5 Stripes on sternites distinct, relatively wide ( Figs 6B, D).................................. Ephemera bistria sp. nov.

- Stripes on sternites indistinct, relatively narrow (as Figs 57B, D)................................................ 6

6 Tergite I without dot or stripe (as Figs 57A, C)............................................... Ephemera shengmi

- Tergite I with two dots or short stripes ( Fig. 63A)............................................. Ephemera glaucops

7 Only tergites I–IV or I–V with a pair of oblique stripes or dots ( Fig. 27A)................... Ephemera pictipennis (male)

- Tergites I–IX with stripes (as Fig. 27C).................................................................... 8

8 Tergites VII–IX with one pair or more straight stripes in dorsal view (as Figs 45A, 54A, C)........................... 9

- Tergites VII–IX with one pair or more oblique stripes in dorsal view (as Figs 60A, C).............................. 12

9 Tergites with red stripes (as Fig. 48A).................................................................... 10

- Tergites with brown to black stripes (as Fig. 54A, C)........................................................ 11

10 Tergites I–IX with two pairs of stripes ( Fig. 45A)........................................ Ephemera rubera sp. nov.

- Tergites I–IX with one pair of stripes ( Fig. 48A)...................................... Ephemera rubrogata sp. nov.

11 Sternites I–III with indistinct stripes ( Figs 54B, D)........................................... Ephemera separigata

- Sternites I–III with distinct stripes ( Figs 27B, D).............................. Ephemera pictipennis (female, in part)

12 Tergites I–VI with more than one pair of stripes ( Fig. 27C)...................... Ephemera pictipennis (female, in part)

- Tergites I–VI without distinct stripe other than lateral pair ( Figs 33A, C)........................................ 13

13 Tergites VII–IX with one pair of oblique stripes only (as Figs 33A, C).......................................... 14 - Tergites VII–IX with more than one pair of stripes (as Figs 13A, C)............................................ 15

14 Length of frons subequal to width in dorsal view ( Fig. 61A)..................................... Ephemera strigata

- Frons clearly longer than wide in dorsal view ( Fig. 34A)..................................... Ephemera pictiventris

15 Mandibular tusks clearly longer than head in dorsal view ( Fig. 14A)......................... Ephemera cornea sp. nov.

- Mandibular tusks clearly shorter than head in dorsal view ( Fig. 22A)....................... Ephemera obliqua sp. nov.