Regulaneuria cingulata ( Navás, 1933 )

Mu, Pengxu & Huang, Xiaolei, 2023, Revision of the genus Regulaneuria (Ephemeroptera, Heptageniidae, Ecdyonurinae), with description of a new species, Zootaxa 5353 (3), pp. 235-249 : 243-245

Regulaneuria cingulata ( Navás, 1933)

( Figs 7A – D , 8D – F )

Thalerosphyrus cingulatus: Navás, 1933: 18 . Types: male imago, from Chusan, Zhejiang, China. Thalerosphyrus cingulatus: Wu, 1935: 252 ; Ulmer, 1936: 215; Gui, 1985: 86; Zhou, 2013: 195; Sartori, 2014: 12; Zhou et al., 2015: 244.

Compsoneuria cingulata: Braasch & Soldán, 1986b: 46 ; Webb, Braasch & McCafferty, 2006: 58. Regulaneuria cingulata: Lei et al., 2021: 8 . Neotype: male imago, from Ningbo, Zhejiang, China.

Material examined (in ethanol). CHINA, Zhejiang: 3 nymphs, Ningbo City, Jiufeng Mountain, Wang’ao [ ZJNB01 Aa] (29°.855356 N, 121°.840133 E, alt. 62 m), 25.III.2023, leg. Pengxu Mu, Danyang Zhou , ( FAFU); 4 male and 6 female imagos, 5male and 2 female subimagos, 6 nymphs, Ningbo City, Jiufeng Mountain , Ruiyan Temple [ ZJNB02 Aa] (29°.832934 N, 121°.867917 E, alt. 73 m), 25.V.2023, leg. Danyang Zhou, ( FAFU); 14 male and 6 female imagos, 1 male and 3 female subimagos, 12 nymphs, Wenzhou City, Jingtou Villiage [ ZJWZ01 Aa] (27°.503969 N, 120°.486747 E, alt. 66 m), 12.V.2023, leg. Pengxu Mu; in ethanol, ( FAFU) .

Complementary description of imago. Almost all crossveins of forewing, except those in costal and subcostal fields and wing base, regularly or roughly arranged into 5 – 6 rows ( Figs 7A – D ).

Complementary description of nymph. Spatulate bristles on upper faces of all femora with truncated apices and without median ridge ( Fig. 8D ); hindtibia with row of pinnate bristles on inner surface and apical half of outer surface ( Fig. 8E ); hindtarsus with pinnate bristles irregularly distributed on inner surfaces, densest at apex ( Fig. 8F ).

Distribution ( Fig. 9A ). China (Zhejiang).

Comments. This species was first reported by Navás (1933) based on male imago and the genitalia were not illustrated. Braasch & Soldán (1986b) transferred this species to the genus Compsoneuria Eaton , which was in accordance with their concept of Compsoneuria . Lei et al. (2021) redescribed the male imago and described the nymph and female imago of this species for the first time, and a neotype was designated because the types were lost. According to the description by the authors, all crossveins on forewings of adults are arranged into five rows, except those in C and Sc fields and wing base ( Fig. 6D , Lei et al. 2021). However, based on our specimens collected from the same localities as well as the figure offered by the authors ( Fig. 5B , Lei et al. 2021), this description is not accurate. Among the 25 male adults we examined, 12 individuals have similar arrangements of crossveins on forewings as stated by the authors, while the other 13 individuals have obviously different arrangements on both or single forewings as in Figs 7B – D ; as for female adults, all 17 individuals we examined have crossveins roughly arranged into six rows as in Fig. 7A .

Regulaneuria cingulata and R. chongchongae sp. nov. can be easily distinguished according to the following differences: In the imaginal stage, A) the arrangement of the crossveins on forewing (two rows in median field contiguous vs. two rows in median field not contiguous); B) the pattern on terga of abdomen (without sublateral spot vs. with pair dark brown sublateral spots); C) the styliger of male (with sublateral projections finger-like vs. with sublateral projections blister-like); in the nymphal stage, A) the lateral part of labrum (not expanded and with a round tip vs. slightly expanded and with a relatively sharpened tip); B) the bristles on upper face of femur (without median ridge vs. with two median ridges); C) the shape of tergalius VII (slightly convex at basal half and with a blunt apex vs. distinctly convex at basal half and with an acute apex).

Figures

FIGURE 5. Regulaneuria chongchongae sp. nov., nymphal structures: A, head capsule; B, labrum, ventral view; C, lateral tip of labrum; D, detail of anteromedial part of labrum; E, mandibles (left: left mandible; right: right mandible); F, hypopharynx, ventral view; G, maxilla, ventral view; H, dentisetae on maxilla (shown in white arrow; dd: distal dentisetae; dp: proximal dentiseta); I, labium, ventral view; J, glossa, ventral view. Scale bar: 1.0 mm (A).

FIGURE 6. Regulaneuria chongchongae sp. nov., nymphal structures: A, legs (fl: foreleg; ml: midleg; hl: hindleg); B, supracoxal spur, hindleg; C, abdominal terga V–X; D, posterolateral spines on abdominal segments V–VIII; E, tergalii (all with the same orientation: anterior margins up, posterior margins down; t1: tergalius I; t2: tergalius II; t4: tergalius IV; t7: tergalius VII); F, caudalii. Scale bar: 1.0 mm (A).

FIGURE 7. Regulaneuria cingulata (Navas, 1933), forewings of imagos: A, female imago; B–D, male imago, different individuals (C–D: left forewing and right forewing of the same individual respectively). Scale bar: 1.0 mm (A–D).

FIGURE 8. SEM photos, Regulaneuria chongchongae sp. nov.: A, bristles on femur; B, bristles on tibia; C, bristles on tarsus. Regulaneuria cingulata (Navás, 1933): D, bristles on femur; E, bristles on tibia; F, bristles on tarsus.Regulaneuria chongchongae sp. nov.: G, dentisetae on maxilla (dd1:; dd2:; dp: proximal dentiseta); H, egg; I, micropyle.

FIGURE 9. A, distribution map of Regulaneuria species; B, habitat of Regulaneuria chongchongae sp. nov.