Siphlonurus dongxi Li & Tong, 2023

Qiang, Xin-He & Zhou, Chang-Fa, 2025, The species diversity and phylogeny of the genus Siphlonurus Eaton, 1868 from China (Ephemeroptera: Siphlonuridae), Zootaxa 5711 (1), pp. 1-56 : 11-14

Siphlonurus dongxi Li & Tong, 2023

Figures 5–6

Siphlonurus dongxi Li & Tong (in Yang et al. 2023: 121 , all stages, from Yunnan Province, China).

Material examined: 2 nymphs, 1♀ imago, 1♂ imago, 1♀ subimago, 1♂ subimago, two exuviae of nymphs, Shangri La, Diqing Prefecture , Yunnan Province, 17.VI.2022, Xianfu Li .

Description: see Yang et al. (2023).

Distribution: China ( Yunnan Province).

Diagnosis

Mature nymph: Body length 14.0–17.0 mm, wingpads with spots ( Figs 5A, B ). Length ratio of first segment of maxillary palp to galea-lacinia about 1.0: 1.3, inner margin of maxillary palp segment II straight ( Fig. 5C ). Posterolateral spines on terga I–IX gradually larger from anterior to posterior, length ratio of posterolateral spine on tergum IX to its tergum = 1.0: 2.0 ( Figs 5D–F ). Each abdominal sternum with two pairs of spots, smaller pair located centrally and larger pair located at posterior corners, small and large spots often fused ( Fig. 5B ). Posterior margin of abdominal sternum IX distinctly convex ( Figs 5E, F ). Both dorsal surface and margins of tergum X with stout and pointed spine-like setae ( Fig. 5G ). Outer margins of dorsal and ventral lamellae of both gills I and II straight, costal rib of dorsal lamella in gill II longer than half of anterior margin ( Figs 5H, I ). Outer and posterior margins of gill III straight, proximal plate of gill VII well developed ( Figs 5J, K ).

Male imago: Body length 17.5 mm, forewing with dark brown crossveins and large dark brown spots between C and Rs 1, distal half of hindwing light brown with spot near middle of R 1 and brown stripe near forking point of MA. All legs generally pale yellow, but ends of femur, tibia, and each tarsal segment noticeably darker, appearing brown ( Figs 6A–C ). Each sternum with pair of dark brown stripes near center, each stripe consisting of central spot and large spot at posterior corner ( Fig. 6D ). Posterolateral spines of abdominal segments VIII and IX relatively small. Inner margin of basal segment of forceps with projection, penis longer than styliger ( Figs 6E–G ). Dorsal elongation of penis straight, spineless, and entirely sclerotized, dorsal sclerotized transverse band of penis without expansion, inner margin of each penis lobe with brown groove, length of two penis lobes ca. 1.2x width ( Figs 6H, I ).

Female imago: Body length 17.0 mm, wings with brown stripe and dots. Color pattern similar to male. Sternum VII extended posteriorly into rectangular lobe, sternum VIII with pair of brown stripe ( Fig. 6J ).

Remarks: For morphological comparison of three closely related species ( S. davidi , S. dongxi , and S. orientalis sp. nov.) see remarks of S. davidi and S. orientalis sp. nov.

Figures

FIGURE 5. Nymph of Siphlonurus dongxi: (A) nymph (dorsal view); (B) nymph (ventral view); (C) maxilla; (D) abdominal terga I–IV (dorsal view); (E) abdominal sternum IX of female (ventral view); (F) abdominal sternum IX of male (ventral view); (G) abdominal tergum X (dorsal view); (H) gill I; (I) gill II; (J) gill III; (K) gill VII.

FIGURE 6. Imago of Siphlonurus dongxi: (A–I) male structures: (A) male imago (lateral view); (B) forewing; (C) hindwing; (D) abdomen (ventral view); (E) genitalia (dorsal view); (F) genitalia (ventral view); (G) genitalia (lateral view); (H) penis (dorsal view); (I) penis (ventral view); (J) sternum VII of female imago.