Argia cuprea Hagen, 1861

Novelo-Gutiérrez, Rodolfo & Gómez-Anaya, José Antonio, 2021, Description of the larva of Argia cuprea (Hagen, 1861) with notes on its phylogenetic affinities (Odonata: Coenagrionidae), Zootaxa 5057 (3), pp. 437-445 : 438-445

Argia cuprea Hagen

Figures 1–6

Material. Three exuviae (2♂♂, 1♀, emerging), 27 F-0 larvae (12♂♂, 15♀♀) , 1 F- 1 larva (♂), 24 younger larvae (11♂♂, 13♀♀). MEXICO: Hidalgo; Municipality of Calnali, Calnali , stream (20° 53.833 N; 98° 35.000 W), elevation 1350 m asl, cloud forest, 10 February 1994, R. Novelo, V. García leg., two exuviae (1♂, 1♀, emerging), nine F-0 larvae, 6♂♂, 3♀♀, one F- 1 larva (♂) , 11 younger larvae (4♂♂, 7♀♀); 19 April 2001, R. Novelo, V. García leg., one exuvia (1♂, emerging), seven F-0 larvae (2♂♂, 5♀♀) , two young larvae (♂, ♀); Municipality of Molango, Pemuxtitla, Río Zacuala (20° 49.933 N, 98° 47.050 W), elevation 1000 m, cloud forest, 10 March 1994, R. Novelo, V. García leg., four F-0 larvae (1♂, 3♀♀) , six younger larvae (2♂♂, 4♀♀); 8 April 1994, R. Novelo, V. García leg., three F-0 larvae (1♂, 2♀♀) . Puebla; Municipality of Cuetzalan del Progreso, Cuetzalan, El Cuichat , stream (20° 00.232 N, 97° 30.691 W), elevation 870, cloud forest, 12 July 2010, R. Novelo, V. García leg., two F-0 larvae (♂, ♀) , three younger larvae (♂♂). San Luis Potosí; Municipality of Xilitla, Xilitla, Las Pozas , stream (21° 23.750 N, 98° 59.717 W), elevation 570 m, tropical forest, 22March 2006, R. Novelo, V. García leg., two F-0 larvae (♂, ♀) , two younger larvae (♂, ♀).

Description. A moderately robust larva ( Fig. 1 ), ground color light yellowish brown to brown with lighter areas. Abdomen cylindrical; caudal lamellae mostly violet on basal 0.60, remainder variable but usually gradually transitioning to white.

Head: Wider than long, posterior margin widely concave, dorsal color light brown ( Fig. 2a ). Labrum yellowish brown, distally setose; clypeus rectangular, light brown, with a pair of parallel, white narrow lines along middle third. Frons and vertex flat, with three pale ocelli. Antennae 7-segmented ( Fig. 2b ), longer than head, scape and 7 th antennomere creamy pale, pedicel and antennomeres 3–6 yellowish-brown; size proportion of antennomeres (from basal to apical): 0.50, 0.55, 1.0, 0.75, 0.45, 0.25, 0.15. Compound eyes large, strongly bulging. Occiput shorter than compound eye dorsal length; cephalic lobes rounded and beset with spiniform setae, posterolateral margins with a dark brown stripe. Mandibles ( Figs. 2c, d ) with molar teeth but lacking molar crest, with following formula: L 1’1 2 3 4 0 a b / R 1’1 2 3 4 y a 0, both mandibles with a ventral and dorsal, transverse, row of setae; basal-external surface setose. Ventral pad of hypopharynx creamy-pale, subrectangular, anterior and posterior margins straight, sides strongly convex, with a tuft of 3–4 long, robust, incurved setae located subapically to each anterolateral corner, and a transverse row of smaller setae on anterior margin. Maxilla: galeolacinia ( Fig. 3a ) with six teeth, three dorsal teeth approximately of the same size, three ventral teeth of different sizes, apical one the longest, a row of stiff setae preceding both ventral and dorsal teeth; maxillary palp shorter than galeolacinia, setose, ending in a robust blunt spine. Labium light yellow. Prementum-postmentum articulation reaching anterior margin of mesosternum. Prementum subpentagonal, 0.26x longer than its widest part ( Fig. 3b ), with a row of 15–19 spiniform setae along distal half of lateral margins, and a group of 4–9 basidorsal spiniform setae of different sizes; ligula strongly convex ( Fig. 3c ), 0.4–0.5 as long as its basal width measured dorsally, with closely set, minute spiniform setae on distal margin. Premental palp ( Fig. 3c ) with two end hooks shorter than movable hook, the ventral (medial) one longest, internal margin of palp finely serrate, dorsoexternal margin with a row of short spiniform setae; external margin of smaller end hook with a row of minute, sharp denticles; only one palp seta ( Fig. 3c ); two stout, spiniform setae at base of palp articulation; movable hook smooth, incurved, sharply-pointed.

Thorax: Pronotal disk subtrapezoid ( Fig. 2a ), flat, mostly light brown with scattered spiniform setae on anterodorsal surfaces, lateral margins reddish yellow, strongly convex, and beset with stout spiniform setae; propleura yellowish brown. Pterothorax mostly yellowish brown with irregular pale and gray areas ( Fig. 1a ). Wing sheaths mostly pale, with venation grayish violet, anterior pair reaching basal half of S5, posterior pair reaching posterior margin of S5. Legs long (i.e., tip of metatibiae surpassing well S10 when fully extended), pro- and mesotibiae longer than respective femora, metafemora and metatibiae of the same length. Femora largely light brown with two pale dorsolateral spots on profemora ( Fig. 3d ) and three on meso- and metafemora; tibiae light brown, with three pale bands ( Fig. 3d ); dorsal and ventral margins of femora, lateral surface of profemora, and internal and external margins of tibiae with spiniform setae, these spiniform setae intermingled with long, stiff setae on dorsal margins of femora and external margins of tibiae; apical-internal margin of tibiae with some thick, robust, reddish, spinelike setae intermingled with long delicate setae; tarsi creamy pale, with a double row of small spiniform setae and long, abundant, yellow, stiff setae on ventral surface, and long, delicate, whitish setae on dorsum; claws simple with pulvilliform empodium.

Abdomen: Cylindrical, wider at base, reaching maximum width at S3 and then slightly and gradually narrowing caudally ( Fig. 1 ). Tergites yellowish brown, posterior margins of S1–9 grayish violet with pale spots regularly spaced. Lateral margins of S1–6 expanded and folded ventrally forming a grayish-violet carina slightly divergent caudally, beset with small spiniform setae on S5–6, not folded and straight on S7–10 with small spiniform setae ( Fig. 1b ); tergites 1–10 with small, abundant, spiniform setae, and abundant, long, erect, stiff, whitish setae along the S2–10 midline; posterior margins of S1–4 smooth, S5–10 with spiniform setae, scattered on S5 and increasingly abundant caudally; posterior margin of S10 with a middle, deep, v-shaped emargination. Sternites mostly light yellow, paler along midline ( Fig. 1b ), grayish-violet laterally and on posterior margins, with small pale spots regularly spaced on posterior margins ( Fig. 1b ). Sternites 1–5 and middle third of 6–7 with sparse, minute, delicate setae (best seen in exuviae), lateral thirds of sternites 6–7 and whole surface of 8–10 with small spiniform setae, closely set on their posterior margins, and stouter on 10. Male gonapophyses ( Figs. 4a, c ) pyramidal, roundly-pointed, in ventral view ( Fig. 4a ) mesial margins slightly divergent, scarcely surpassing posterior margin of sternite 10; ventrolateral surface with 30–32 short, roundly-pointed, scale-like setae; in lateral view as Fig. 6c . Female gonapophyses ( Fig. 4b, d ) scarcely exceeding posterior margin of S10; lateral valves, in ventral view ( Fig. 4b ), roundly-pointed, ventral margin with 30 or more small, scale-like setae on basal 0.75; in lateral view ( Fig. 4d ) with 2–3 minute spiniform setae on lateral surface; median valves smooth, as long as lateral valves. Male cerci short ( Fig. 5 ), roundly pointed in caudal and dorsolateral views ( Figs. 5a, b ). Female cerci more or less triangular in lateral view. Caudal lamellae of combined type, saccoid-laminar ( Fig. 6 ) narrowing at both ends with acuminate tips; most of lamellae with a more or less uniform violet coloration on basal 0.60, remainder variable but usually degrading gradually to white ( Figs. 6a–c ). Lateral lamella (paraproct) ( Figs. 6a–c ) moderately inflated laterally on basal 0.60, apical 0.40 laminar, 2.5x longer than its widest part; a triangular, basolateral, longitudinal, yellow-brown, slightly sclerotized area along the inflated part of lamella bearing short spiniform setae, this area slightly closer to the inferior margin of lamella than to the dorsal one; dorsal margin with spiniform setae on basal 0.10, remainder smooth with sparse, small, white, delicate setae, which increase in length and abundance on apical 0.40 including tip; ventral margin with spiniform setae on basal 0.13, remainder as dorsal margin; tip approximately 20% of the total length. Central lamella (epiproct) ( Fig. 6d ) moderately inflated at basal 0.55 on both sides, 2x longer than its widest part; a triangular sclerotized area similar to that of lateral lamella on basal 0.25 at both sides of epiproct, bearing spiniform setae; dorsal margin with spiniform setae on basal 0.03, remainder mostly smooth, fringed with white, long, delicate setae on apical 0.40 including tip; ventral margin smooth on basal 0.60, remainder fringed with white setae which increase in length caudally; tip approx. 20% of the total length; color pattern as in Fig. 6d .

Measurements [averages in brackets]: Total length (without caudal lamellae) 12.5–14.1 [13.12; N=16]; maximum width of head 4.0–4.3 [4.14; N=16]; hind femur 4.0–4.6 [4.28; N=16]; abdomen 6.5–8.2 [7.24; N=16]; paraprocts (with tip) 5.0–6.6 [6.04; N=23]; epiproct (with tip) 3.8–5.8 [4.44; N=14].

Diagnosis. Argia cuprea falls into the group of Argia larvae with very prominent ligula and one palpal seta ( Novelo-Gutiérrez 1992). It shows a closer resemblance to the larvae of A. barretti Calvert, 1902 , A. harknessi Calvert, 1899 , A. insipida Hagen in Selys, 1865, A. joergenseni Ris, 1913 , A. oenea Hagen in Selys, 1865, A. orichalcea Hagen in Selys, 1865, and A. percellulata Calvert, 1902 by the coloration and size proportions of antennomeres, one palpal seta, ligula very prominent, male and female gonapophyses roundly tipped and with scale-like setae, caudal lamellae of combined type saccoid-laminar. However, the larva of A. cuprea differs from the above-mentioned species [in square brackets] by the following (features of A. insipida taken from Geijskes [1943], those of A. orichalcea taken from Geijskes [1946 as A. “difficilis ”][see comments under A. oenea in Novelo-Gutiérrez 1992) (species not mentioned into square brackets implies they are similar to A. cuprea ): basidorsal spiniform setae on prementum 4–9 [3 in A. insipida , 3–5 in A. orichalcea , 10–11 in A. barretti , 15–21 in A. percellulata ]; male gonapophyses reaching posterior margin of sternite 10 [shorter, not reaching posterior margin of sternite 10 in A. barreti , A. harknessi , A. joergenseni , A. oenea , A. orichalcea , and A. percellulata (as in Figs. 7a, b )]; bases of male gonapophyses not reaching posterior margin of sternite 8 [reaching posterior margin of sternite 8 and forming a laterally convex carina in A. barretti , A. harknessi , A. insipida , and A. joergenseni ( Fig. 7a )]; dorsal and ventral margins of paraproct with long, abundant, white, delicate setae on distal 0.40 [short delicate setae on distal 0.20–0.30 in A. barreti and A. insipida ; with long, abundant, golden, stiff setae on distal 0.50 in A. oenea ( Fig. 7c ), and apparently similar on distal 0.33 of A. orichalcea ; margins mostly smooth with a few, scattered, minute white setae on distal half in A. harknessi ( Fig. 7d )]; tip of paraproct 20% its total length [40% in A. oenea , 33% in A. orichalcea , 10% or less in other species]; lateral surface of paraproct with abundant spiniform setae restricted to the triangular, yellow-brown, slightly sclerotized area along the inflated part [abundantly setose on all the lateral surface in A. oenea (cf. Figs. 7b,c ); setose throughout lateral midline in A. percellulata ]; epiproct distal end widely rounded and with a short tip [epiproct acuminate in A. oenea ( Fig. 8b ) and A. orichalcea ]; epiproct mostly violet [epiproct mostly white with irregular, dark markings in A. harknessi ( Fig. 8c ), A. joergenseni , and A. orichalcea ; with three tranverse dark bands and four white spots in A. oenea ( Fig. 8b ); mostly dark gray in A. insipida and A. percellulata ; largely mottled in A. barretti ]; femora largely brown with two pale spots [femora with three pale bands in A. barretti , A. harknessi ( Fig. 8d ), A. insipida , A. joergenseni , A. orichalcea , and A. percellulata ]; abdomen yellowish brown usually with a middorsal, thin, pale, longitudinal line [with large, triangular, middorsal pale spots on each tergite in A. percellulata ; a wide, dark brown, parallel-sided, middorsal longitudinal stripe with a pair of small, pale spots on each tergite in A. barretti and A. harknessi ; a wide, middorsal, pale longitudinal stripe in A. joergenseni and A. orichalcea ].

Habitat. Larvae of Argia cuprea inhabit small shallow streams, crawling among debris, gravel, cobblestones where the water flow is moderate or slow, close to the shoreline.

Figures

FIGURE 1. Argia cuprea, habitus dorsal (a) and ventral (b) of F-0 male larva.

FIGURE 2. Argia cuprea, details of larval morphology. a) Head and prothorax, dorsal view; b) right antenna, ventral view; c) right mandible, ventrointernal view; d) left mandible, internal view.

FIGURE 3. Argia cuprea, details of larval morphology. a) Right maxilla, ventral view; b) prementum, ventral view; c) Ligula and palpi, dorsal view; d) left foreleg.

FIGURE 4. Argia cuprea, details of larval morphology. a) S8–10 and male gonapophyses, ventral view; b) S8–10 and female gonapophyses, ventral view; c) male gonapophyses, lateral view; d) female gonapophyses, lateral view.

FIGURE 5. Argia cuprea, male cerci. a) Caudal view; b) dorsolateral view (caudal lamellae detached).

FIGURE 6. Argia cuprea, caudal lamellae. a–c) Lateral lamellae showing the pigmentation variation (a and c right lamellae, b left lamella); d) central lamella, left lateral view.

FIGURE 7. Argia spp., S8–10 and caudal lamellae. a–b) Ventral view of male gonapophyses of A. harknessi and A. oenea, respectively; c–d) caudal lamellae of A. oenea and A. harknessi, respectively, ventral view.

FIGURE 8. Argia spp., details of larval morphology. a) A. harknessi, left lamella; b) A. oenea, central lamella, left lateral view; c) A. harknessi, central lamella, left lateral view; d) A. harknessi, left foreleg.