Euphaea superba, Kimmins, 1936

Wu, Xiangjuan, Liu, Zhen, Chen, Yu & Wang, Beixin, 2019, Description of larva of Euphaea superba Kimmins, 1936 (Odonata: Zygoptera: Euphaeidae) from China, Zootaxa 4545 (4), pp. 585-592 : 587-590

Larvae of Euphaea superba

Specimens examined. 2 larvae: 1♂, 13.V.2016, Xiaxuezhaicun (29 ° 31’58’’N, 119 ° 52’1’’E), Jinhua City, Zhejiang Province, China, Lei Zhang leg ; 1♀, 26.V.2017, Shuijinkeng (29 ° 15’47’’N, 120 ° 58’23’’E), Taizhou City, Zhejiang Province, China, Lei Zhang leg. All specimens are deposited in the Insect Collection, Nanjing Agricultural University .

Description ( Figs. 2–25 ). Male. Body medium-sized and flat; in dorsal view black covered (in alcohol) with dense black setae ( Fig. 2 ), in ventral view light brown mottled with yellow spots ( Fig. 3 ).

Head: Roughly pentagonal ( Fig. 2 ), greyish brown mottled with yellow stripes, densely covered with short rod-like setae intermingled with small simple setae dorsally. Compound eyes black, somewhat round. Ocelli white and elliptic. Mid-portion of antefrons with inverted T-shaped stripe. Antenna 7-segmented ( Fig. 4 ), filiform; 1 st segment short and thick, black; 2 nd segment slender, about two times as long as 1 st one, black except yellow apex; 3 rd –6 th segments each with base and apex yellow and other portion black; 7 th segment, light brown, thin with apex acute. Clypeus yellowish brown, stripe-like, glabrous. Genae large ( Fig. 5 ), somewhat bottle-shaped, anterior 1/3 much narrower than posterior 2/3; of seven sharp spines on anterolateral margin of both genae, forth to sixth spines larger than other ones in left gena ( Fig. 6 ), and fifth to seventh spines larger than other ones in right gena ( Fig. 7 ); each gena has rows of short setae along lateral margin contiguous with compound eye extending to posterolateral area of rod-like setae. Labrum ( Fig. 10 ) wider than long, with anterior margin concave, dorsal surface densely covered with short rod-like setae intermingled with simple setae laterally, except glabrous triangular area at middle. Mandibles unsymmetrical, somewhat conical, with following formula: L 1’+1234 0 a(m 1,2,3,4)b / R 1’+1234 y aa’. Left mandible with five incisiors and two molars ( Fig. 11, 12 ); incisiors sharp, incisior 1’ small and blunt, close to incisior 1, 4>3>2>1>1’; molar a and b sharp, a> b; four denticles between molar a and b sharp. Right mandible with five incisiors and two molars ( Fig. 13, 14 ); incisiors sharp, incisior 1’ small and blunt, close to incisior 1, 4>3>1>2>1’; molar a and a’ sharp, a> a’; additional tooth y with sharp apex. Basolateral spines of each mandible progressively larger. Maxillae ( Fig. 16, 17 ) long, each with galeolacinea ( Fig. 15 ) having four strong uncinate teeth, and basal half of apical tooth with three blade-like teeth, inner margins of galeolacinea setose; maxillary palpi digitate, slightly curved inwards, distal half setose. Labium flattened. Prementum ( Fig. 18 ) longer than wide, median lobe semicircular, median cleft shallow, lateral margins each with row of compactly arranged uncinate spines. Lateral lobe black, each cylindrical, apex with one inner truncate tooth and two outer uncinate teeth ( Fig. 19 ), with median uncinate tooth largest and incisive; movable hook strong, about twice length of abovementioned largest tooth, with apex sharp.

Thorax: Prothorax narrower than head ( Fig. 2 ), wider than long. Pronotum roughly saddle-shaped, dark brown to black, covered with rod-shaped setae intermingled with small simple hairs, except white diamond-shaped depression at middle, and brown cambered glabrous stripe issued from anterolateral angle and extended to diamond-shaped depression, then backward to posterolateral angle on each side. Synthorax as wide as head, setose as pronotum except anteromesal triangular area and adjacent two oblique stripes. Mesonotum rectangular. Metanotum triangular. Prosternum with pale distinct spot mesally. Prosternum, meso- and meta-sternum depressed in the middle ( Fig. 3 ), each with paired depressions laterally. Wing sheaths divergent, dark brown, with sparse short rod-like setae, hind wing sheaths each reaching posterior margin of 7 th abdominal segment. Of three paired legs, forelegs shortest and hind legs longest. Legs overall brown, with tarsi and claws yellowish brown; femora broad, robust, covered with dense setae intermingled with short rod-like setae, posterior margin with sparse long rod-like setae interspersed long bristle-like setae in dorsal view; tibiae slender, setose, interminglesd with sparse long rodlike setae and long bristle-like setae on each outer margin; tarsi with bristle-like setae on dorsal surfaces and dense spines on ventral surface, tarsal formula 3-3-3; claws glabrous.

Abdomen: Abdominal segments dark brown, each with posterior margin light brown; S3–S8 each with a pair of crescent yellow spots dorsally ( Fig. 2 ); sterna of S2–S7 each with yellow longitudinal line and pair of roughly round yellow spots ( Fig. 3 ); seven pairs of lateral gills ( Fig. 20 ) from S2–S8, each gill progressively slenderer from base to end, with dense tiny curving setae on ventral margin. Vestigial male primary genitalia ( Fig. 21 ) inconspicuous, present on S9, paired, stripe-shaped, with simple setae on ventral margin. Caudal gills saccular, dark brown, distal portion with a short pale tail, median gill ( Fig. 24–25 ) with dense simple setae, near tail with sparse rod-like setae, distal half with dense long bristle-like setae on ventral margin at middle; lateral gills resemble median gill but smaller.

Measurements (mm). Body length (including caudal gills) 23.5; head width 4.8; antenna length 2.7; labrum width 1.3; left mandible length 1.6, right mandible length 1.6; prementum length 4.2, prementum width 3.2; hindwing sheath length 6.7; median gill 6.7.

Female. Female larva resembles male larva, except larger body size, 4 th –7 th spines larger than other ones in left gena ( Fig. 8 ), and 5 th –6 th spines larger than other ones in right gena ( Fig. 9 ). Moreover, female primary genitalia ( Fig. 22–23 ) extend to posterior margin of S10. Primary lateral valvulae in ventral view narrow at base, slightly broadened laterad to basal 1/3, then narrowed progressively to apex, setose on inner margins, apex rounded ventrally; in lateral view, upper margin somewhat sinuate, lower margin arch-shaped, apex nipple-shaped. Primary ventral valvulae slender in ventral view, tapering from base to apex, in lateral view slightly curved upwards. Primary inner valvulae similar to primary ventral valvulae both in ventral and lateral views, but slenderer.

Measurements (mm). Body length (including caudal gills) 24.1; head width 5.0; antenna length 2.9; labrum width 1.4; left mandible length 1.7, right mandible length 1.7; prementum length 4.3, prementum width 3.3; hindwing sheath length 6.9; median gill 6.9. Female primary genitalia length 1.3.

Habitat. Larvae were collected from the underside of raised rocks in a hill stream with rapid flow. The stream is about six metres wide and with about 60% canopy of riparian vegetation.

Diagnosis. The larva of E. superba could be diagnosed from E. decorata , E. formosa , E. ochracea and E. yayeyamana by the combination of following characters (according to the descriptions and illustrations of various authors): (1) movable hook about 1.6 times as long as median cleft of labium (7.5 times in E. decorata , 3 times in both E. formosa and E. ochracea , and 2.6 times in E. yayeyamana ); (2) the median caudal gill with the base about 10 times as long as its tail (2.5 times in E. decorata , 5 times in E. ochracea , and 3 times in E. yayeyamana , unknown in E. formosa ); (3) 2–4 large and sharp spines on outer side of gena (2–3 in E. decorata , 3–5 in E. formosa and E. ochracea , and 3 in E. yayeyamana ); (4) female with primary genitalia extend to posterior margin of S10 (extend beyond distal margin of S 10 in E. decorata , E. formosa , E. ochracea and E. yayeyamana ).

Figures

FIGURES 2–3. Larva of male Euphaea superba with mandibles removed: (2) dorsal view; (3) ventral view. Scale bars = 5 mm.

FIGURES 4–9. Larva of Euphaea superba: (4) male right antenna, dorsal view; (5) male left gena, ventral view; (6) spines on male left gena, ventral view; (7) spines on male right gena, ventral view; (8) spines on female left gena, ventral view; (9) spines on female right gena, ventral view. Scale bars = 1 mm.

FIGURES 10–19. Larva of male Euphaea superba: (10) labrum, anterior view; (11) left mandible, internal view; (12) left mandible, ventral view; (13) right mandible, internal view; (14) right mandible, ventral view; (15) left galeolacinea, dorsal view; (16) left maxilla, dorsal view; (17) left maxilla, ventral view; (18) prementum, ventral view; (19) right lateral lobe, dorsal view. Scale bars = 1 mm.

FIGURES 20–25. Larva of Euphaea superba: (20) male lateral abdominal gills, ventral view; (21) vestigial male primary genitalia, lateral view; (22) female primary genitalia, ventral view; (23) female primary genitalia, lateral view; (24) male median gill, ventral view; (25) male median gill, lateral view. Scale bars = 1 mm.