Afronurus hunanensis ( Zhang & Cai, 1991 )

Zhang, Wei, Lei, Zhi-Ming, Li, Wen-Juan & Zhou, Chang-Fa, 2021, A contribution to the genus Afronurus Lestage, 1924 in China (Ephemeroptera: Heptageniidae, Ecdyonurinae), European Journal of Taxonomy 767 (1), pp. 94-116 : 106-109

Afronurus hunanensis ( Zhang & Cai, 1991)

Figs 4C–D , 6C , 7D–F , 10–11 , 12B , 13C–D

Cinygmina hunanensis Zhang & Cai, 1991: 237 , figs 1–9 (male, male subimago). Types: male, male subimago, from Hunan, China.

Cinygmina hunanensis – You & Gui 1995: 54, fig. 53 (male). — Zhou & Zheng 2003: 756, figs 11, 15 (male).

Afronurus hunanensis – Braasch & Jacobus 2011: 64.

Material examined

Holotype CHINA • ♂; Hunan Province, Zhang-Jia-Jie city, Jin-Bian creek ; 29°20′45.14″ N, 110°32′46.36″ E; alt. 253 m; 18 Jun. 1986; J. Zhang and S.S. She leg.; NNU.

Paratypes CHINA • 9 ♂♂, 3 ♀♀; same collection data as for holotype; NNU .

Additional material

CHINA • 25 ♂♂, 22 ♀♀, 16 nymphs; Hunan Province, Chen-Zhou city, Mang-Shan National Forest Park; 24°58′55.92″ N, 112°51′22.32″ E; alt. 511 m; 7 Aug. 2020; Z.X. Ma leg.; NNU .

Description

Nymph (first description, Figs 7D–F , 10–11 )

MEASUREMENTS. Body length 7.0– 8.5 mm, caudal filaments 15.0–17.0 mm long.

COLORATION. Body brown to dark brown.

HEAD. Head capsule ellipsoid, anterior margin unicolor, posterior margin slightly concave and with 4 pale dots in the middle of the compound eyes ( Fig. 7D ). Labrum ca half width of head, lateral margins expanded slightly; free margin nearly straight, both surfaces with setae but those on dorsal surface relatively longer and denser; ventral surface with shallow median groove, an additional row of bristles on ventral anterior margin ( Fig. 10A ). Both mandibles covered with numerous long setae on outer margins; prostheca with 5–7 fimbriate bristles ( Fig. 10C–D, G–H ); outer incisor of left mandible with serrated margin and a large terminal denticle; inner incisor divided into 3 blunt denticles ( Fig. 10C, G ); outer incisor of right mandible serrated with 2 apical terminal denticles; inner one divided into 2 sharp denticles ( Fig. 10D, H ). Hypopharynx: apex of superlinguae extended into round lobe-like structures, row of long hair-like setae on lateral margins from base to apex; lingua bell-like, much shorter than superlinguae, apex with tuft of setae ( Fig. 10B ). Maxillae with fimbriate setae on ventral surface ( Figs 4D , 10F ), row of 16–18 comb-shaped setae on crown of galea-lacinia, middle combs with 10–13 teeth, distal dentisetae branched, proximal dentisetae bifid and fringed ( Fig. 4C ); maxillary palpi 3-segmented, basal segment with scattered setae on both outer and inner margins, second segment with long setae on outer margin and terminal segment with setal brush ( Fig. 10F ). Labium: glossae lobe rounded, inner margins slightly expanded, with tuft of long setae; paraglossae expanded into distinct lobes, with dense setae and bristles on dorsal surface and outer margin; labial palpi 2-segmented, ventral surface and free margin of second segment with setal brush ( Fig. 10E ).

THORAX. Pronotum slightly extended laterally, subequal in length to head ( Fig. 7D ). Supracoxal spurs rounded. Femora of all legs with acute and spatulate setae on dorsal surfaces, outer margins with long setae and inner margins with short bristles. Foretibia subequal in length to femur, outer margin with tiny setae at base; foretarsi approximately ⅓ length of tibiae ( Fig. 11A ). Midleg similar to foreleg, but tibia 0.89× of femur in length, outer margin and dorsal surface with rows of sparse setae ( Fig. 11B ). Hindleg similar to midleg except tibia 0.7× of femur in length and dorsal surface of tibia with long and short bristles ( Fig. 11C–D ). Claws of all legs with 4 subapical denticles ( Fig. 11E ).

ABDOMEN. Abdominal terga I pale or with transverse brown band; terga II–VII brown with pair of pale dots medially, and terga IV–V, VII with adlateral dots; terga VIII–IX pale but with pale thin stripe anteriorly; tergum X brown with 2 small pale longitudinal stripes ( Fig. 7E ); terga II–VIII with weakly developed posterolateral angles. Gill I banana-shaped, trachea visible ( Fig. 11F ); gills II–VI heart-like and lamellae expanded laterally ( Fig. 11G ), gills V–VI with arrowlike accessory lobes ( Fig. 11H ); gill VII slightly asymmetrical, with fine marginal setae ( Fig. 11I ). Caudal filaments with whorls of spines on articulations, proximal part pale and other parts yellowish brown ( Fig. 7F , as in Fig. 1B ).

Male imago

See Zhang & Cai (1991: 237, figs 1–9, original description) and Zhou & Zheng (2003: 756, figs 11, 15).

Egg ( Fig. 6C )

Ovoid, small KCTs concentrated at each pole, chorion smooth, large KCTs and oval micropyles located equatorially.

Remarks

The nymphs of A. hunanensis and A. yixingensis can be separated into one group due to the anterior margins of head capsules being without any dot. However, the following characters can help differentiate them: 1) lingua of A. hunanensis is much shorter than superlinguae ( Fig. 10B ) but in A. yixingensis it is subequal in length (as in Fig. 8B ); 2) glossae of A. hunanensis are round ( Fig. 10E ) while slightly oblong in A. yixingensis (as in Fig. 2F ); 3) number of comb-shaped setae on maxillae: 16–18 in A. hunanensis (middle combs with 10–13 teeth) and 12–14 in A. yixingensis (middle combs with 7–10 teeth); 4) gill VII of A. hunanensis is broad ( Fig. 11I ) but narrow, leaf-like in A. yixingensis (as in Fig. 9F ); 5) caudal filaments of A. hunanensis are pale at base and yellowish-brown in other parts ( Fig. 7F ), whereas caudal filaments of A. yixingensis have dark brown dots on every two or three segments ( Fig. 7O ).

In male imago, A. hunanensis has plate-like titillators and bifurcated apices of penial lobes ( Fig. 13C–D, I–J ). In contrast, A. yixingensis has spine-like titillators and a remarkable projection between divergent penial lobes.

Distribution

China (Hunan, Jiangxi, Guizhou).

Figures

Fig. 4. SEM photos of nymphal maxillae. A. A. drepanophyllus sp. nov. (NNU). B. A. furcatus (Zhou & Zheng, 2003) (NNU). C. A. hunanensis (Zhang & Cai, 1991) (NNU). A–C. Dentisetae. D. Enlarged scattered setae on ventral surface; the three species have similar structures (labels show distal dentisetae and proximal dentisetae respectively). Abbreviations: see Material and methods.

Fig. 6. SEM photos of eggs. A. Afronurus drepanophyllus sp. nov. (NNU). B. A. furcatus (Zhou & Zheng, 2003) (NNU). C. A. hunanensis (Zhang & Cai, 1991) (NNU). D. A. obliquistriatus (You et al., 1981) (NNU). E. A. rubromaculatus (You et al., 1981) (NNU). F. A. yixingensis (Wu & You, 1986) (NNU).

Fig. 7. Nymphal habitus of five species of Afronurus Lestage, 1924. A–C. A. furcatus (Zhou & Zheng, 2003) (NNU). D–F. A. hunanensis (Zhang & Cai, 1991) (NNU). G–I. A. obliquistriatus (You et al., 1981) (NNU). J–L. A. rubromaculatus (You et al., 1981) (NNU). M–O. A. yixingensis (Wu & You, 1986) (NNU). A, D, G, J, M. Head capsule. B, E, H, K, N. Abdominal terga. C, F, I, L, O. Caudal filaments. Scale bars: A–B, D–E, G–H, J–K, M–N = 2.0 mm; C, F, I, L, O = 1.0 mm.

Fig. 10. Mouthparts of Afronurus hunanensis (Zhang & Cai, 1991) (NNU). A. Labrum (ventral view). B. Hypopharynx (ventral view). C. Left mandible (ventral view). D. Right mandible (ventral view). E. Labium. F. Maxillae. G. Incisors of left mandible. H. Incisors of right mandible. Scale bars: A–D, F = 0.5 mm; E = 1.0 mm; G–H = 0.1 mm.

Fig. 11. Nymphal structures of Afronurus hunanensis (Zhang & Cai, 1991) (NNU). A. Foreleg. B. Midleg. C. Hindleg. D. Hindleg tibia. E. Foreleg claw. F. Gill I. G. Gill II. H. Gill VI. I. Gill VII. Scale bars: A–C = 1.0 mm; D–F = 0.5 mm; G–I = 0.3 mm.

Fig. 12. Male abdominal terga of five species of Afronurus Lestage, 1924. A. A. furcatus (Zhou & Zheng, 2003) (NNU). B. A. hunanensis (Zhang & Cai, 1991) (NNU). C. A. obliquistriatus (You et al., 1981) (NNU). D. A. rubromaculatus (You et al., 1981) (NNU). E. A. yixingensis (Wu & You, 1986) (NNU). Scale bars = 1.0 mm.

Fig. 13. Genitalia of five species of Afronurus Lestage, 1924. A–B. A. furcatus (Zhou & Zheng, 2003) (NNU). C–D. A. hunanensis (Zhang & Cai, 1991) (NNU). E–F. A. obliquistriatus (You et al., 1981) (NNU). G–H. A. rubromaculatus (You et al., 1981) (NNU). I–J. A. yixingensis (Wu & You, 1986) (NNU). A, C, E, G, I. Genitalia. B, D, F, H, J. Penes enlarged; arrows show titillators. Scale bars: A, C, E, G, I = 0.5 mm; B, D, F, H, J = 0.2 mm.

Fig. 1. Nymph of Afronurus drepanophyllus sp. nov. (NNU).A. Nymphal habitus. B. Selected segments, enlarged, of terminal filament and right cercus (dorsal view). Scale bars: A = 2.0 mm; B = 0.1 mm.

Fig. 8. Mouthparts of Afronurus furcatus (Zhou & Zheng, 2003) (NNU). A. Labrum (ventral view). B. Hypopharynx (ventral view). C. Left mandible (ventral view). D. Right mandible (ventral view). E. Labium. F. Maxillae. G. Incisors of left mandible. H. Incisors of right mandible. Scale bars: A, C–D, F = 0.5 mm; B = 0.3 mm; E = 1.0 mm; G–H = 0.1 mm.

Fig. 2. Mouthparts of Afronurus drepanophyllus sp. nov. (NNU). A. Labrum (ventral view). B. Median bristles of ventral labrum. C. Hypopharynx (ventral view). D. Left mandible (ventral view). E. Right mandible (ventral view). F. Labium. G. Maxillae. H. Incisors of left mandible. I. Incisors of right mandible. Scale bars: A, C–G = 0.5 mm; B = 0.3 mm; H–I = 0.2 mm.

Fig. 9. Nymphal structures of Afronurus furcatus (Zhou & Zheng, 2003) (NNU). A. Foreleg. B. Midleg. C. Hindleg. D. Hindleg tibia. E. Foreleg claw. F. Gill I. G. Gill II. H. Gill VI. I. Gill VII. Scale bars: A–D = 1.0 mm; E–I = 0.3 mm.