Leptagrion acutum Santos, 1961

Furieri, Karina S., Fraga, Felipe B., Tribull, Carly & Colombo, Wesley D., 2020, Description of two females of Leptagrion Selys (Odonata: Coenagrionidae), Zootaxa 4821 (2), pp. 343-352 : 344-346

Leptagrion acutum Santos, 1961

( Figs 1–2 )

Leptagrion acutum Santos, 1961 , 21 (4): 359 [Holotype: ♂, BRAZIL: Espírito Santo, MNRJ].

Specimens examined. ♂, BRAZIL, E[spírito] S[anto], Conceição da Barra , Reserva Biológica do Córrego Grande ( RBCG), 18º16’12.1”S 39°48’56.9”W, 18-XII-2005, Furieri, K.S., Loiola, G. R., Van de Kaken, A.F. cols .; ♀, BRA-ZIL, E[spírito] S[anto], Conceição da Barra , Reserva Biológica do Córrego Grande, Lagoa dos Guaxos—Km 6, 18º16’19.3”S 39°48’54.8”W, 13-III-2006, Furieri, K.S., Van de Kaken, A.F., Redighieri, E.S. cols . ♀, BRAZIL, E[spírito] S[anto], Conceição da Barra , Reserva Biológica do Córrego Grande, Mata de Tabuleiro (flying over bro-meliads), 18º15’04.1”S 39°49’12.8”W, 15-III-2005, Kawada, R., Furieri, K.S., Silva, R. R. cols .

Additions to the description of the male. Head. Mandible with two apical teeth, distinctly larger upper tooth; clypeus light blue; anteclypeus trilobate; postclypeus with anterior margin straight, two circular, castaneous, lateral depressions; antefrons weakly blue and white; postfrons with dark castaneous depression; ocelli protuberant.

Thorax. Prothorax castaneous coloured; anterior lobe dark castaneous; middle lobe light castaneous, dorsal margin straight; posterior pronotal lobe mostly dark castaneous, light castaneous laterally, dorsal margin concave. Pterothorax with mid-dorsal carina delimited; mesostigmal plate castaneous; mesepisternum mostly dark castaneous, elongated, as wide as mesepimeron; antealar crest dark castaneous; mesopleural suture delimited, sinuous; mesopleutal fossa black, oval; mesinfraepisternum rectangular; mesepimeron light castaneous, as wide as metespiternum; interpleural suture delimited, long; second thoracic spiracle light castaneous, oval; metinfraepisternum dark castaneous; metespiternum light castaneous, wider than metepimeron; metapleural suture delimited; metapleural fossa black, oval; metepimeron, light castaneous, wide posteriorly.

Wings. Hyaline, with pruinose spots at each wing base, venation brown. Pterostigma blackish brown bordered by brown venation, rhomboid.

Abdomen. S1 brown with whitish yellow lateral marking; S2–S6 dorsally brown, ventrally yellowish; S7–S10 dorsally dark brown, ventrally yellowish. Cercus dark brown, in lateral view, bifurcating at 2/3 of its length into a large dorsal branch and a thinner tapering ventral one. In dorsal view the dorsal branch appears as a large acute tubercle covered with a small tuft of hairs directed distally. From the medial border of the ventral branch stems two stout subterminal tooth directed medially.

Genital ligula. Proximal process forming flagellum, long; one pair internal fold near to base of flagellum, in ventral view; apical lobe with one pair of latero-distal projections, narrow; first segment wide with upper sclerotized dark band, in lateral view.

Measurements. TOL: 62.0; LA: 51.0; HW: ~26.8.

Description of the female. Head. Mandible with two apical teeth, distinctly larger upper tooth; anteclypeus straight; postclypeus with anterior margin weakly incurved, two circular, castaneous, lateral depressions; antefrons weakly blue and white; postfrons with dark castaneous depression; ocelli protuberant.

Thorax. Prothorax castaneous coloured; anterior lobe dark castaneous; middle lobe light castaneous, dorsal margin straight; posterior pronotal lobe mostly dark castaneous, light blue laterally, dorsal margin straight. Pterothorax with mid-dorsal carina weakly delimited; mesostigmal plate dark castaneous; mesepisternum mostly dark castaneous, light blue ventrally, elongated, narrower than mesepimeron; antealar crest dark castaneous; mesopleural suture delimited, sinuous; mesopleutal fossa black, circular; mesinfraepisternum rectangular; mesepimeron dark castaneous, wider than metespiternum; interpleural suture delimited, long; second thoracic spiracle light castaneous, oval; metinfraepisternum dark castaneous; metespiternum light castaneous, narrower than metepimeron; metapleural suture delimited; metapleural fossa black, oval; metepimeron, light castaneous, wide posteriorly.

Wings. Hyaline, with pruinose spots at each wing base, venation black. Pterostigma blackish brown bordered by brown venation, rhomboid.

Abdomen. Segments similar to male, except genital valve surpassing S10, ventral margin with short bristles and denticulate. Ovipositor and appendages brown.

Measurements. TOL: 49.0–50.0; LA: 40.0–41.0; HW: ~22.0–25.0.

Differential Diagnosis. The female of this species resembles that of L. porrectum by having pterostigma in fore and hind wings rhomboid; ovipositor valves surpassing distal margin of S10; and tarsal claws with robust inferior tooth subequal to superior. However, the female of L. acutum has the posterior lobe of prothorax with straight dorsal margin when seen in lateral view; the pterothorax with interpleural suture long and distinct; and, S8 sternum with distal margin not surpassing distal margin of S8 tergum. In contrast, the female of L. porrectum has posterior lobe of prothorax with concave dorsal margin when seen in lateral view; pterothorax with interpleural suture short and indistinct; and, S8 sternum with distal margin surpassing distal margin of S8 tergum.

Distribution. Brazil (Espírito Santo).

Figures

FIGURE 1. Leptagrion acutum, male. (A) Habitus, lateral view. (B) Thorax, lateral view. (C) Thorax, dorsal view. (D) Abdominal segments, lateral view. (E) Abdominal segments, ventral view. Scales: 1 mm.

FIGURE 2. Leptagrion acutum, female. (A) Habitus, lateral view. (B) Thorax, lateral view. (C) Thorax, dorsal view. (D) Abdominal segments, lateral view. (E) Abdominal segments, ventral view. Scales: 1 mm.