Peristicta aeneoviridis Calvert, 1909

Schröder, Noelia M., Anjos-Santos, Danielle, Rippel, Camila G. & Pessacq, Pablo, 2020, Description of the last instar larva of Peristicta aeneoviridis Calvert, 1909 (Odonata: Coenagrionidae), Zootaxa 4728 (4), pp. 461-468 : 462-465

Peristicta aeneoviridis Calvert, 1909

( Figures 1–2 )

Peristicta aeneoviridis Calvert (1909) : male description; Fraser (1947): record for Misiones Province, Argentina; Santos (1968): in part, wing characters’ variation; Pessacq (2007): male redescription, genital ligula and cercus figures, distributional map, synonymy of P. misionera with P. aeneoviridis ; Anjos-Santos & Pessacq (2013): genital ligula figures, included in key.

Peristicta misionera Jurzitza (1981) : sp. nov. male description.

Larva diagnosis: Small-sized coenagrionid, with one pair of premental setae, caudal lamellae ovoid with ill-defined nodus and marginal light marks, femur with one apical, one basal and two medial dark bands.

Last instar larva description.

Specimens examined: Two exuviae (1 ♂, 1 ♀ both emerged in laboratory), and corresponding adults. AR- GENTINA: Misiones Province, Parque Provincial Cañadón de Profundidad, Profundidad stream (-27,74533°, - 55,70958°, 155 m asl), 17 i 2019, N.M. Schröder & C.G. Rippel leg. 1 F-0 larva (emerged in laboratory 15 ii 2019, 1 ♂, 12 ii 2019 1 ♀).

Head. About 1.6 times as wide as long, posterior margin slightly concave, cephalic lobes with several short ovoid setae and few thin hair-like setae. Antenna with six antennomeres, 1 st and 4 th with 1/3 basal dark brown, remaining brown, 2 nd and 3 rd antennomeres light brown with distal half pale yellow, 6 th antennomere pale yellow, proportional lengths of antennomeres: 0.9:0.8:1:1:0.9:0.6. Premental articulation reaching first coxae; prementum ( Fig. 1a ) short and broad, about 1.2 times as long as wide, anterior margin triangular and crenulated, with one premental seta on each side; lateral sides with a row of 9–11 short spine-like setae at distal third. Palp ( Figs 1b, c ) external margin crenulated, with four long setae; distal margin with the typical curved end hook and externally to this, two or three very small medial teeth and three external short, stout spines-like setae ( Fig. 1c ); inner margin crenulated; movable hook slender and acute, about a third the length of external margin. Mandibles as in Figure 1d . Mandibular formula L 1+2345 0 ab; R 1-2345 y a Maxilla ( Fig. 1e ): laciniae ( Figs 1 e–g) with six teeth: three dorsal ones ( Fig. 1f ) slightly incurved, similar in shape and size and three ventral ones ( Fig. 1g ) with different size and shape: the apical one similar to the dorsal ones, remaining ones smaller, proportions as follows: 1:0.3:0.2. Basal to the dorsal teeth there is a row of long plumose setae: two thick and remaining ones thin; basal to the ventral teeth there is a row of three long, thick, hair-like setae and several short thin, plumose setae. Galeae ( Figs 1e ) gently incurved, apex stout, rounded, with long, plumose setae on the external surface, base (Fig. h) with several short spine-like setae.

Thorax. Pronotum and synthorax dark brown with two dorsal pale bands. Wing pads nearly parallel, reaching S5. Legs ( Figs 2 a-d) slender, covered by small hair-like setae, light brown; coxae brown; trochanter base dark brown; femora with one apical, one basal and two medial dark bands ( Fig. 2a ), the distal one wider; prothoracic femora with a row of ovoid setae on flexor and extensor margin, remaining surface with a few ovoid setae ( Figs 2b, c ); meso- and metathoracic femora flexor margin with a row of scattered ovoid setae, even less developed in extensor margin. Tibiae ( Fig. 2a ) with a dark band on apical third, more pronounced in the prothoracic leg, extensor surface with long thin, hair-like setae, apical flexor third ( Fig. 2d ) with abundant plumose and tridentate setae. Tarsi extensor surface with long, thin hair-like setae, flexor surface with two ventral rows of plumose setae, claws simple and equal.

Abdomen. Cylindrical, dark brown, with two dorsal longitudinal lighter bands at both sides of the medial line; S1–4 with thin setae on dorsal surface; S6–10 with a distal row of spines, sparse on S6. Male and female cerci are damaged and cannot be described. Male gonapophyses sharply pointed and divergent, with thin setae, surpassing anterior margin of sternum 10. Female gonapophyses reaching sternite 10, outer valves sharply pointed, inner valves rounded. Caudal lamellae ( Figs. 2e, f ) brown, with light marks on margins, ovoid, apex rounded, nodus ill-defined, distal 1/3 of margin with several long hair-like setae, surface covered by very small hair-like setae. Lateral lamellae ( Fig. 2f ) more than 3 times as long as their wider section, dorsal margin with 20–23 spine-like setae, denser and larger towards the apex, ventral margin with 53–55 spine-like setae, larger towards the apex, lateral carina with a row of 29–31 spine-like setae, basal region with four short thick spine-like setae. Median lamella ( Fig. 2e ) 3 times as long as its wider section, with four ovoid setae on its basal region, dorsal margin with 40 spine-like setae, denser and larger towards the apex, ventral margin with 27–29 spine-like setae, larger towards the apex, lateral carina with 23–26 spine-like setae.

Measurements (in mm): male (n=1): head maximum width 2.5, head maximum length 1.4, prementum maximum length 1.3, prementum maximum width 1, femur I length 2, femur II 2.5, femur III 3.2, tibia I length 0.9, tibia II 1.3, tibia III 2, external wing pads length 2.6, internal wing pads length 2.5, cerci 0.2, lateral caudal lamellae 2.3, central caudal lamellae 2.4. Female (n=1): head maximum width 2.6, head maximum length 1.6, prementum maximum length 1.2, prementum maximum width 1, femur I length 1.3, femur II 1.6, femur III 2.3, tibia I length 1.1, tibia II 1.2, tibia III 1.5, external wing pads length 2.6, internal wing pads length 2.5, cerci 0.1, lateral caudal lamellae 2.2, central caudal lamellae 2.2.

Remarks. Provincial Park Cañadón de Profundidad is located in the Candelaria department, near the city of Posadas, Misiones Province. This reserve presents a shallow stream “Arroyo Profundidad” ( Fig. 4 ), with a variable flow dependent on rainfall. A dense canopy forest with native species is present along the stream, largely blocking solar radiation. The stream bed is rather stony and with little or no aquatic vegetation but with debris from riparian vegetation. The larvae were collected among vegetation debris on the margin of the stream in areas of low current. The air temperature was 30 ºC, and the stream water temperature was 24ºC, and pH 7,58.

Figures

FIGURE 1. Last instar-lava of Peristicta aenoviridis: a) prementum, dorsal view; b) left labial palp, dorsal view; c) labial palp external margin details; d) mandibles, inner view: right (R) and left (L); e) left maxilla, ventral view; f) left lacinia dorsal teeth; g) left lacinia ventral teeth; h) galea base detail.

FIGURE 2. Last instar-lava of Peristicta aenoviridis: a) right prothoracic leg, ventral view; b) prothoracic femur details, ventral view; c) setae on prothoracic femur, ventral view; d) protibia, ventral view; e) median caudal lamella, left lateral view; f) lateral caudal lamella, left lateral view.

FIGURE 4. Collection site. Arroyo Profundidad, Provincial Park Cañadón de Profundidad, Candelaria Department, Misiones Province, Argentina.