Heteragrion cauei Ávila-Jr., Lencioni & Carneiro, 2017

(Figs. 21a–e)

[Key locator: Key to Group A species, couplet 22 (21)]

Heteragrion cauei: Ávila-Jr. et al. 2017: 275–286 (description of ♁ and ♀ from Minas Gerais state, Brazil; diagnosis and comparison with other congeners; figs. 2–7);— Ávila Jr. et al. 2021: 3, 5–6 (list of species, IUCN status; figs. 3a, 5);— Guedes et al. 2022: 5 (list of species) .

Material examined. 1♁ (PARATYPE) BRAZIL, Minas Gerais state, Ouro Preto, Cachoeira Catarina Mendes, 18.iii.2016, (-20.3447, -43.4986, 1082m asl), W.F. Ávila-Jr. leg., ABMM ; 1♁ same date, but 2.iii.1987, A.B.M. Machado leg., ABMM .

Known distribution. Brazil (Southern Minas Gerais state).

Diagnosis and remarks. Heteragrion cauei is close morphologically to H. consors, sharing the large upper plate on ML. It can be separated from the latter by the shape of upper and lower plates. The following character combination distinguishes this species from the remainder of Group A species: upper plate subequal in size with lower plate (Fig. 21e), rounded shape, wider than lower plate, bearing a posterior row of teeth, not centered with lower plate (Figs. 21c–e); lower plate narrow, bearing two carinae and squared apex (Fig. 21e). Heteragrion cauei has been assessed as Vulnerable on the IUCN Red List, as it currently is known from only a limited region with continuous habitat quality decline (Vilela & Guillermo-Ferreira 2021c).