Angelagrion, Lencioni, 2008

Lencioni, Frederico A. A., 2008, Angelagrion gen. nov. with description of A. nathaliae sp. nov. and A. fredericoi sp. nov. from Brazil (Odonata: Coenagrionidae), Zootaxa 1968, pp. 23-32 : 24

Angelagrion gen. nov.

Figures 1–9

Type species: Angelagrion fredericoi sp. nov. by present designation.

Etymology: Named Angela after my beloved wife Angela Schmidt Lourenço Rodrigues – and agrion, neuter form of agrios meaning "wild", which in damselflies is now used as an indicator that a genus belongs to the Coenagrionidae ( Fliedner 2006) .

Generic characterization. Head. Frons angulated in profile; pale postocular spots present; most posterior point of head at compound eyes ( Figs. 1a – 3a).

Thorax. Posterior lobe of prothorax approximately rectangular and slightly trilobed, and mesostigmal plates triangular in both sexes ( Figs. 5a–c); hind margin of interlaminal sinus prominent, meeting mid-dorsal carina at an obtuse angle; mid-dorsal carina narrowed before interlaminal sinus. Wings petiolated at or slightly before CuP ( Figs. 4a–b); CuP reaching CuP&AA or posterior margin of wing; CuA extending for 3–7 cells posterior to vein descending from subnodus; 3–4 cells between quadrangle and vein descending from subnodus in Fw; RP 2 in Fw beginning slightly beyond Px 4–5 and in Hw at Px 4; pt costal side 3 times longer than distal side ( Figs. 4a–b), distal and proximal sides of pt subequal. Spurs on distal half of metafemur shorter than width of femur; metatibial spurs shorter than intervening spaces.

Abdomen. In both sexes mostly blue with black markings; S2–5 or S2–6 with a black mid-dorsal stripe terminating in an angulated expansion joined or not with the black apical annulus, which is expanded basally at varying degrees; S8–10 dark brown to black; sternum of S 8 in males with a circular bluish-white spot (unique for genus). Male cercus dark, in lateral view much shorter than S10, approximately rounded; male paraproct entire, in lateral view about twice the length of cercus ( Fig. 6a). Female S8 lacking vulvar spine; female cercus much shorter than S10; tergum of S10 with a very short dorso-posterior cleft. Ovipositor robust and long, with a single row of teeth along ventral margin of outer valves, and tip (excluding stylus) extending to tip of cerci ( Figs. 6d–e). Posterior margin of S9 of female without denticles ( Figs. 6d–e).

Male genital ligula with portion of distal segment distal to flexure gradually narrowing to a narrow, slightly spatulate apex about as wide as 0.25 of portion proximal to flexure; ental surface of distal segment with small sclerotized spines arranged in three groups; inner fold prominent, broad at base, as long as 0.70 of portion distal to flexure, and as wide as portion proximal to flexure; terminal fold present but small, its medial portion notched ( Figs. 7a–e). Larva unknown.

Diagnosis. Angelagrion possesses the following combination of characters which separate both species from all other described Coenagrionidae : S8–10 varying from dark brown to black in both sexes contrasting with mostly pale blue remainder of abdomen, circular bluish-white spot on sternum of S8 of males and internal fold of genital ligula modified as a bellows which opens when distal segment is extended ( Figs. 7b, d), and a short CuA (shared with Aceratobasis mourei (Santos) , Calvertagrion St. Quentin , Chrysobasis Rácenis , Dolonagrion Garrison & von Ellenrieder , some Homeoura Kennedy , Leptobasis , Mesoleptobasis Calvert , and Telagrion Selys ).