Afronurus furcatus ( Zhou & Zheng, 2003 )

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 : 100-106

Afronurus furcatus ( Zhou & Zheng, 2003)

Figs 4B, D , 6B , 7A–C , 8–9 , 12A , 13A–B

Cinygmina furcata Zhou & Zheng, 2003: 755 , figs 1–6. Types: male and female adults, from Tian-Mu Mountain, Zhejiang Province, China.

Afronurus furcatus – Braasch & Jacobus 2011: 64.

Material examined

Holotype CHINA • ♂; Zhejiang Province, Lin-An city, Tian-Mu Mountain , San-Mu-Ping ; 30°21′53.06″ N, 119°25′53.99″ E; alt. 780 m; 29 Jul. 1998; M.S. Zhao leg.; NNU.

Paratypes CHINA • 2 ♂♂, 4 ♀♀; same collection data as for holotype; NNU .

Additional material

CHINA • 7 ♂♂, 15 ♀♀, 5 nymphs; Zhejiang Province, Long-Quan city, Shuang-Xi village ; 27°53′16.34″ N, 119°12′55.17″ E; alt. 1391 m; 3 Aug. 2020; Z.X. Ma and X.H.Y. Zheng leg.; NNU .

Description

Nymph (first description, Figs 7A–C , 8–9 )

MEASUREMENTS. Body length 7.0–10.0 mm, caudal filaments 13.0–18.0 mm long.

COLORATION. Generally yellowish to brown.

HEAD. Head capsule subquadrate, anterior margin of head with 4 small pale dots and basal part of antennae with 2 pale dots; posterior margin of head slightly concave and with 4 pale dots between the compound eyes ( Fig. 7A ). Labrum 0.5× width of head, laterally tapering and slightly curved; anterior margin with shallow emargination; an additional row of short bristles on ventral anterior margin ( Fig. 8A ). Both mandibles covered with numerous setae on outer margins; prostheca with 6–8 fimbriate bristles ( Fig. 8C– D, G–H ); outer incisor of left mandible with serrated margin and one larger terminal denticle; inner incisor shorter than outer incisor and with 3 blunt denticles ( Fig. 8C, G ); outer incisor of right mandible serrated and with 2 apical terminal denticles; inner one divided into 2 sharp denticles ( Fig. 8D, H ). Hypopharynx: apex of superlinguae strongly curved and extended into round lobe-like structures, long hair-like setae up to the lower part of superlinguae; lingua bell-like, subequal to superlinguae in length and with tuft of setae at apex ( Fig. 8B ). Maxillae with scattered fimbriate setae on ventral surface ( Figs 4D , 8F ), row of 17–20 comb-shaped setae on crown of galea-lacinia, middle combs with 10–15 teeth, distal dentisetae branched, proximal dentisetae bifid ( Fig. 4B ); maxillary palpi with setae on outer margin and basal half of inner margin of first segment; segment II longer than the former one and outer margin with long setae, terminal segment with dense setal brush ( Fig. 8F ). Labium: glossae lobe rounded, inner margin slightly expanded, with tuft of long setae; paraglossae expanded greatly into palpable lobes, with dense setae and bristles on dorsal and free margins; labial palpi 2-segmented, ventral surface and free margin of second segment with setal brush, dorsal surface with scattered golden setae ( Fig. 8E ).

THORAX. Pronotum slightly expanded laterally, wider than head ( Fig. 7A ). Supracoxal spurs rounded. Femora of all legs with row of long setae on outer margins, dorsal surfaces with spatulate setae and inner margins with short bristles. Foretibia subequal in length to femur, outer margin with sparse hair-like setae near base, inner margin with row of bristles; foretarsi 0.4× as long as tibiae, outer and inner margins with tiny setae ( Fig. 9A ). Midleg similar to foreleg except tibia 0.91× of femur in length, outer margin with row of hair-like setae, dorsal surface with rows of hair-like setae and bristles; tarsi approximately ⅓ length of tibia ( Fig. 9B ). Hindleg tibia 0.8× of femur in length, outer margin and dorsal surface with rows of long setae and bristles, inner margin with row of bristles and very tiny setae ( Fig. 9D ); tarsi about ¼ length of tibia ( Fig. 9C ). Claws of all legs with 3–4 subapical denticles ( Fig. 9E ).

ABDOMEN. Abdominal terga I–VII yellowish to brown, with 3 pale dots medially and 2 pale dots laterally; terga VIII–IX with fused pale dot medially; tergum X dark brown, anterior margin with 3 light pale dots ( Fig. 7B–C ). Gill I banana-shaped, inner margin slightly curved ( Fig. 9F ); gills II–IV heart-like and with lamellae expanded laterally ( Fig. 9G ); gills V–VI oval, with additionally arrow-like accessory lobes ( Fig. 9H ); gill VII oval, with fine marginal setae, trachea clearly visible ( Fig. 9I ). Caudal filaments pale, with whorled spines on articulations ( Fig. 7C , as in Fig. 1B ).

Male imago

See Zhou & Zheng (2003: 755, figs 1–6, original description).

Egg

Oval, chorion mostly smooth and decorated with small KCTs at each pole, larger KCTs located equatorially ( Fig. 6B ).

Remarks

The male imago of A. furcatus is similar to the one of A. hunanensis due to color pattern of abdominal terga, plate-like titillators and bifurcated apices of penial lobes. However, they can be separated by the following characters: 1) the body color of A. furcatus is bright yellow when it is alive ( Fig. 12A ) while reddish brown in A. hunanensis ( Fig. 12B ); 2) A. furcatus has slightly divergent penial lobes, which are connected by a foliated structure ( Fig. 13A–B ), while penes of A. hunanensis are obviously divergent and with deeply cleft ( Fig. 13C–D ); 3) the plate-like titillators of A. hunanensis are smaller than in A. furcatus ( Fig. 13A–D ).

In the nymph, A. furcatus resembles A. drepanophyllus sp. nov., A. obliquistriatus and A. rubromaculatus because of marking patterns on head capsules. However, the following combination of characters can help to separate them: 1) head capsule of A. furcatus has one row (4 dots) of pale dots on anterior margin ( Fig. 7A ), while A. drepanophyllus sp. nov. has two rows (generally 2–5 dots) of pale dots on anterior margin ( Fig. 1A ), A. obliquistriatus and A. rubromaculatus have two rows (generally 8–9 dots) on anterior margins ( Fig. 7G, J ); 2) linguae and superlinguae are approximately the same length in A. furcatus , A. drepanophyllus sp. nov. and A. rubromaculatus ( Fig. 2C , 8B ); however, the lingua of A. obliquistriatus is much shorter than superlinguae (as in Fig. 10B ); 3) number of comb-shaped setae on maxillae: 13–15 in A. drepanophyllus sp. nov. (middle combs with 9–13 teeth), 17–20 in A. furcatus (middle combs with 10–15 teeth), 11–13 in A. obliquistriatus (middle combs with 8–10 teeth) and 14–16 in A. rubromaculatus (middle combs with 10–12 teeth); 4) caudal filaments of A. furcatus are pale ( Fig. 7C ) whereas in A. drepanophyllus sp. nov. they are pale near the base and yellowish-brown in other parts ( Fig. 1A ); A. obliquistriatus and A. rubromaculatus have dark brown dots on articulation ( Fig. 7I, L ).

Distribution

China (Jiangxi, Zhejiang).

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. 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. 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.

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. 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. 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.