Epeorus (Proepeorus) aculeatus Braasch, 1990

Ma, Zhen-Xing, Lei, Zhi-Ming, Li, Wen-Juan & Zhou, Chang-Fa, 2021, A revision of Epeorus (Proepeorus) in China, with descriptions of two new species (Ephemeroptera, Heptageniidae), Journal of Natural History 55 (17 - 18), pp. 1131-1159 : 1141-1142

Epeorus (Proepeorus) aculeatus Braasch, 1990

Figs 5A–B , 12D , 13F , 15D , 16I

Epeorus aculeatus Braasch, 1990, p. 7 , Figures 1–8 (nymph). Types: nymph, from Thailand .

Epeorus aculeatus: Nguyen and Bae 2004, p. 19 (nymph); Webb and McCafferty 2006a, p. 65 (male).

Materials examined

One male imago, Futian Village, Eryuan Town , Niujie County, Yunnan Province, collected by Wei ZHNAG, Zhen-Xing MA, 3-11-IV-2018; 1 nymph (1400 m a.s.l.), Jianfeng River , Zhonghe Town , Tengchong City, Yunnan Province, collected by Hui XIE, Yan-Yan JIA, Ping CHEN, 20-VII-2008; 8 nymphs, Laomane (1255 m a.s.l.), Menghai County , Xishuangbanna, Yunnan Province, collected by Ning DING, 21-III-2008; 6 nymphs, Mengyuan Village , Mengla County , Xishuangbanna, Yunnan Province, collected by Yun-Lei ZHOU, 14-III -2013; 2 nymphs, Dutian Village (103°54′47.99″N, 23°11′5.67″E), Wenshan City, Yunnan Province, collected by Zhen-Xing MA, 17-X-2020; 5 nymphs, Xiaoyaodian Village (103°56′ 6.27″N, 23°17′56.55″E), Wenshan City, Yunnan Province, collected by Zhen-Xing MA, 17- X-2020 .

Diagnosis and remarks

E. (P.) aculeatus can be distinguished from other congeners by the following characters. In male imago ( Figures 12 (d) and 13(f)): 1) penes are fused basally and widely divergent apically, each penis lobe shallowly notched apically; 2) base of penes with small median titillators; 3) unique colouration of abdominal terga and sterna (see Webb and McCafferty 2006a: Figures 1–2 ). In nymph: posterior margin of abdominal terga II–IX with a pair of long submedian spines ( Figure 5 (b)).

Kluge (2004) placed E. (P.) aculeatus in the subgenus Epeorus s.str., but the presence of median titillators on penes of male indicates that E. (P.) aculeatus is belonging to subgenus Proepeorus . In addition, some new records of Chinese ‘paired-spines’ species (with submedian paired spines or tubercles on nymphal terga, including Epeorus rhithralis Braasch, 1980 , Epeorus bispinosus Braasch, 1980 and Epeorus bifurcatus Braasch & Soldán, 1979 ), which have a close relation with E. (P.) aculeatus but have not been described in adult stages, are also included in this work and regarded as Proepeorus species for the time being.

Distribution

China (Yunnan), Thailand, Vietnam.

Figures

Figure 1. Nymph of Epeorus spp.: (a–c) Epeorus (Proepeorus) nipponicus: (a) Nymphal habitus, (b) Head capsule, (c) Abdominal terga VII–X; D–F: Epeorus (Proepeorus) unispinosus: (d) Nymphal habitus, (e) Head capsule, (f) Abdominal terga VII–X.

Figure 2. Nymphal habitus and structures of Epeorus (Proepeorus) gibbus sp. nov.: (a) Nymphal habitus (dorsal view); (b) Nymphal habitus (ventral view); (c) Head capsule; (d) Abdominal tergum (segment VII); (e) Gill VII (ventral view); (f) Middle leg.

Figure 3. Mouthparts of Epeorus (Proepeorus) gibbus sp. nov. (digital photos): (a) Labrum; (b) Left mandible; (c) Right mandible; (d) Hypopharynx; (e) Maxillae; (f) Labium.

Figure 4. Nymph of Epeorus (Proepeorus) gibbus sp. nov.: (a) Head capsule; (b) Labrum (ventral view on left, dorsal view on right); (c) Right mandible; (d) Left mandible; (e) Glossae of labium (dorsal view on left, ventral view on right); (f) Femoral setae; (g) Claw; (h) Abdominal tergum VII (dorsum); (i) Posterior margin of tergum VII (vertical line is midline of tergum); (j) Gill I; (k) Gill II; (l) Gill VII.

Figure 5. Nymphal habitus and abdominal terga of Epeorus (Propeorus) spp.: A–B: E. (P.) aculeatus, (a) Nymphal habitus, (b) Abdominal terga VII–X; C–D: E. (P.) bispinosus, (c) Nymphal habitus, (d) Abdominal terga VII–X; (e, f): E. (P.) bifurcatus, (e) Nymphal habitus, (f) Abdominal terga VII–X; (g, h) E. (P.) rhithralis, (g) Nymphal habitus, (h) Abdominal terga VII–X.

Figure 6. Nymphal structures of Epeorus spp.: (a–c) Labrum, (a) Epeorus (Epeorus) melli, (b) Epeorus (Propeorus) nipponicus, (c) E. (P.) unispinosus; (d, e) Gill I, (d) E. (P.) unispinosus, (e) E. (P.) bifurcatus; (f–h) Posterior margin of tergum VII, (f) E. (P.) bispinosus, (g) E. (P.) rhithralis; (h) E. (P.) bifurcatus.

Figure 7. Nymphal habitus and structures of Epeorus (Proepeorus) falcatus sp. nov.: (a) Nymphal habitus (dorsal view); (b) Nymphal habitus (ventral view); (c) Head capsule; (d) Abdominal tergum (segment VII); (e) Gill VII (ventral view); (f) Middle leg.

Figure 8. Mouthparts of Epeorus (Proepeorus) falcatus sp. nov. (digital photos): (a) Labrum; (b) Left mandible; (c) Right mandible; (d) Hypopharynx; (e) Maxillae; (f) Labium.

Figure 12. Genitalia of male: (a) Epeorus (Proepeorus) gibbus sp. nov. (ventral view); (b) Epeorus (Proepeorus) falcatus sp. nov. (ventral view); (c) Epeorus (Proepeorus) nipponicus (ventral view); (d) Epeorus (Proepeorus) aculeatus (ventral view).

Figure 13. Genitalia of male: (a, b) Epeorus (Proepeorus) gibbus sp. nov., (a) Ventral view, (b) Dorsal view; (c) Epeorus (Proepeorus) nipponicus (ventral view); (d, e) Epeorus (Proepeorus) falcatus sp. nov., (d) Ventral view, (e) Dorsal view; (f) Epeorus (Proepeorus) aculeatus (ventral view).

Figure 15. Mouthparts of Epeorus (Proepeorus) spp.: (a–f) labrum, (a) E. (P.) nipponicus; (b) E. (P.) unispinosus; (c) E. (P.) bifurcatus; (d) E. (P.) aculeatus; (e) E. (P.) rhithralis; (f) E. (P.) bispinosus; (g–i) base of apical tooth complex of maxilla, (g) E. (P.) gibbus sp. nov.; (h) E. (P.) falcatus sp. nov.; (i) E. (P.) nipponicus.

Figure 16. Incisors of left mandible in ventral view: (a) Epeorus (Epeorus) melli; (b) Epeorus nguyeni; (c) Epeorus (Proepeorus) nipponicus; (d) Epeorus (Belovius) pellucidus; (e) Epeorus (Proepeorus) unispinosus; (f) Epeorus (Proepeorus) gibbus sp. nov.; (g) Epeorus (Iron) alexantri; (h) Epeorus (Proepeorus) falcatus sp. nov.; (i) Epeorus (Proepeorus) aculeatus; (j) Epeorus (Proepeorus) bifurcatus; (k) Epeorus (Proepeorus) bispinosus; (l) Epeorus (Proepeorus) rhithralis.