Heteragrion cooki Daigle & Tennessen, 2000

(Figs. 26a–d)

[Key locator: Key to Group A species, couplet 8’]

Heteragrion cooki: Daigle & Tennessen 2000: 255–259 (description of ♁ and ♀; diagnosis and comparison with H. alienum and H. aurantiacum; figs. 1–10);— De Marmels 2004: 447 (comparison with H. makiritare and other Heteragrion species; figs. 18–19);— Tennessen & Johnson 2008: 9–11 (list of species from southern Ecuador);— Garrison et al. 2010: 88, 91 (list of Heteragrion species; figs. 387–388);— Rivas-Torres et al. 2017: 123–135 (demographics and behavioral ecology);— Medina-Espinoza 2022: 236–240 (first record to Peru).

Material examined. 1♁ ECUADOR, El Oro Province, Piedras, 4.vii.1941, (-3.6333, -79.9166, 300m asl), D.B. Laddey leg., ABMM ; 4♁♁ Bosque Seco Lalo Loor, 30.xi.2012, (-0.0834, -80.1485, 65m asl), A.C. Rivera leg., ECOEVO ; 6♁♁ El Oro, Cantón Piñas, 18.vi.2016, (-3.6529, -79.7652, 532m asl), I. Sanmartín-Villar & A. Rivas-Torres leg., ECOEVO .

Known distribution. Ecuador and Peru.

Diagnosis and remarks. This species shares with H. silvarum and H. cinnamomeum the cercus with a long BP, ending in subequal MP and AP, with a developed ML. The following character combination distinguishes this species from the remainder of Group A species: BP the longest cercus portion, nearly straight (Figs. 26c–d); on the MP, ML broad, bearing an elevated ridge (Fig. 26c); ML apex with a small cleft (Fig. 26d).