Ephemera (Sinephemera) bistria 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 bistria

description: Ephemera (Sinephemera) bistria sp. nov. (Figs 6–12, 64)
Description
Nymph: Length: body 16.0–18.0 mm, caudal filaments 4.0–5.0 mm. Length and width of frons subequal, two anterior projections slightly divergent (Figs 6, 7A). Black band between two lateral ocelli (Fig. 7A). Mouthparts: anterolateral corners of labrum semicircular, dorsal and ventral surfaces of labrum with golden hair-like setae (Fig. 8A); two mandibular tusks subequal in length, length subequal to head length (Figs 6, 7A). Outer incisor of left mandible divided into 4 spurs, inner one divided into 3 (Fig. 8E); outer incisor of right mandible divided into 3, inner one divided into 2; mesal margin with a row of hair-like setae (Fig. 8D). Segments I and III of maxillary palpi subequal in length, segment II slightly shorter; segments II–III with relatively long hair-like setae, mesal margin with more those kind of setae than outer margin; segment III with acute apex (Fig. 8F). Lingua and superlinguae with dense hair-like setae on apical margins (Fig. 8B). All parts of labium with golden hair-like setae, apical segment of labial palpi with spine-like setae on apex (Fig. 8C). Pronotum with one pair of submedian stripes and black anterior and posterior margins (Figs 6, 7A); forewing pads with distinct brown transverse band or markings (Figs 6A, C). Legs with golden hair-like setae on all parts, hindcoxae with clear black marking (Figs 7B–D). Gills I–IV on posterolateral angles, gills V at middle point of lateral margin, gills VI–VII at anterolateral angles; gills I much smaller than gills II (Figs 7E–F). Abdominal tergite I with very shallow median ridge (not visible in some individuals) (Fig. 7G). Color pattern of abdomen: tergites I–IX with three pairs of longitudinal stripes, lateral pair wider and blacker than other two pairs; median pair on tergites I–IV or I–V sometimes indistinct; two submedian pairs of stripes usually fused together at both ends, delimiting paler dash and dot in-between; markings on tergite X indistinct (Figs 6A, C). Sternites I–X with pair of longitudinal stripes, those on sternite I and X usually very small and indistinct (Figs 6B, D).
Male imagine: Body length 15.0–16.0 mm, forewing 13.0–14.0 mm, hindwing 4.0–5.0 mm, caudal filaments 26.0–27.0 mm. Head and thorax chocolate dorsally but pronotum with median pale area (Figs 9A, 10A); all coxae blacker than other parts of legs respectively, hindcoxae totally black to chocolate (Fig. 9A). Forecoxae and forefemora blacker than others, base and apex of foretibiae brown. Wings transparent, veins brown, all crossveins blackened, especially those in C and Sc fields (Fig. 9A); forewing with median black band (several dots or markings at median part of forewing forming a transverse row), crossveins in stigmatic area usually anastomosed (Fig. 11A); MP 2 and CuA fused at base, A 1 with 5–6 veinlets (Fig. 11B); veins of hindwing brown, margins and crossveins near margins tinged with amber to light brown (Fig. 11C). Tergites I–II smooth (Fig. 11D); tergites I–X black, with pale middle line and two pairs of pale stripes, but in most cases lateral pair indistinct (Figs 9A, 10A). Sternites I–X with pair of wide black stripes (Figs 9A, 10B). Caudal filament brown (Fig. 9A).
Genitalia: Brown, posterior margin of styliger plate nearly straight. Segment I of forceps longer than combined length of segments III–IV, the latter ca. half the length of segment II. Apices of segments II–IV slightly expanded. Penes shorter than segment I of forceps, space between them subequal to width of penis tapered, lateral half sclerotized (Fig. 11E); outline of apical penes smooth (Fig. 11F).
Female imagine: Body length 15.0–16.0 mm, caudal filament 15.0–16.0 mm, forewings 15.0–16.0 mm, hindwings 5.0–6.0 mm. Except sexual differences, color patterns of body and wings similar to nymph and male imagine, but paler or much paler than in male imagine, lateral margins of tergites with black stripes (Figs 9B, 10C–D, 12). Foretibiae and foretarsi blacker than other parts of forelegs, basal half of mid- and hindtibiae blacker than others. Hindcoxae with distinct black marking (Figs 9B, 10D, 12D). Caudal filament brown. Tergite I with an indistinct hump (Fig. 12D).
Male subimagine: unknown.
Female subimagine: similar to female imagine but legs paler.
Diagnosis: (1) In nymphs and adults of this species, the color pattern of body is unique: tergites (more distinct in males and female tergites VII–IX) have three pairs of longitudinal stripes and two median pairs fused at both ends (Fig. 10). Those stripes are much blacker and wider in the male adults, giving the abdomen a pale midline with one or two pairs of pale stripes. Sternites of this species have one pair of longitudinal stripes (Figs 9–10). (2) The male genitalia have a relatively short penes but long segment I of forceps (Figs 11E–F). (3) The black spot on hindcoxae of this species is remarkable (Fig. 12D). (4) Tergites I or I–II have no distinct spines (Figs 11D, 12D), the hindwings have no distinct marking (Figs 11C, 12C). In general, this species is relatively smaller and blacker than other species in the same genus.
Comparison:A similar genitalia and longitudinal stripes on abdomen can be found in E. shengmi (Figs 56–58) and E. glaucops (Fig. 63). But the abdominal stripes in E. bistria sp. nov. are much blacker and wider than in the other two species, especially those of sternites. In addition, the stripes on tergites of E. shengmi and E. glaucops are unfused.
Etymology: the specific name bistria is combined from Latin prefix “ bi- ” (two, double) and word “ stria ” (noun, stripe), indicating this species has two distinct stripes on its sternites and two fused pairs on tergites VII–IX.
Material: China: Holotype (♂ imagine), Limu Mt. park (19.168205°N, 109.745829°E), Qongzhong county, Hainan province, leg. De-Wen Gong, Xing-He Qiang & Xiao-Fang Chen, 2023-IV-15–21. Paratypes: 1 nymph, same as the holotype; 1 ♂ and 1 ♀ imagines, Wu-Zhi-Shan Mt. park (18.907855°N, 109.679361°E), Hainan province, leg. Xu-Hong-Yi Zheng & Zhi-Teng Chen, 2023-IV-17. Other material: 3 nymphs, Lian-Hua-Ping, Wuyi Mt., Fujian province, leg. Wei Zhang & Zhi-Min Lei, 2021-IV-15; 15 nymphs, Si-Xing logo camp, Wuyi Mt., Fujian province, leg. leg. Xu-Hong-Yi Zheng & Zhi-Min Lei, 2022- III- 13; 4 nymphs, Lian-Hua-Ping, Wuyi Mt., Fujian province, leg. Zhen-Xing Ma, De-Wen Gong & Peng-Xu Mu, 2021- III- 18; 1 ♂ imagine, Shang-Rao, Jiangxi province, leg. leg. Zhen-Xing Ma & leg. Xu-Hong-Yi Zheng, 2021-V-5; 1 ♀ imagine, Bang-Liang protection station, Jiangxi county, Guangxi Province, Leg. Hai-Yang Xu, 2018-V-1; 10 ♀ imagines and 2 ♀ subimagines, Dan-Jiang village, Rongjiang county, Guizhou province, leg. Peng Li and Zhi-Jie Wang, 2005-IX-13–17; 20 ♀ imagines, 10 ♀ subimagines, Lian-Hua-Ping, Leishan county, Guizhou province, leg. Peng Li and Zhi-Jie Wang, 2005-IX-17–18; 5 ♀ imagines, 5 subimagines, same locality, 2005-VI-10; 3 ♀ imagines, Fan-Jin Shan, Guizhou province, leg. Yu-Zhou Du, 1994-VI-19; 2 nymphs, Lan-Zhu forestry, Chishui county, Guizhou province, leg. Chang-Hai Sun & Bei-Xing Wang, 1996-VI-9.
Distribution: Southern China (Hainan, Guangxi, Guizhou, Fujian, Jiangxi).
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 11-17, DOI: 10.11646/zootaxa.5517.1.1, http://zenodo.org/record/13915182