Mecistogaster, Rambur, 1842

Soldati Lacerda, Déborah S. & Monteiro Machado, Angelo B., 2019, The damselfly genus Mecistogaster (Odonata: Pseudostigmatidae) from the Brazilian Atlantic Forest with a description of three new species and a neotype designation for M. amalia (Burmeister, 1839), Zootaxa 4668 (2), pp. 207-228 : 209

Key to males of Mecistogaster recorded in the Brazilian Atlantic Forest

1. Costal margin at level of pseudostigma of HW not projected anteriorly; cerci in lateral view straight........... M. linearis

1’. Costal margin at level of pseudostigma of HW abruptly projected anteriorly ( Fig. 12 ); apex of cerci in lateral view bent ventrally ( Fig. 28 )........................................................................................ 2

2. Anterior hamule with alula ( Fig. 17 )...................................................................... 3

2’. Anterior hamule without alula ( Fig. 18 ).................................................................... 4

3. Mesepimeron totally reddish-brown ( Fig. 9 ); penis segment 2 in ectal view with one lateral elevation, in lateral view with contour foot-shaped ( Figs 23, 24 ).................................................................... M. amalia

3’. Mesepimeron with reddish-brown area restricted to lower 1/5 of sclerite ( Fig. 8 ); penis segment 2 in ectal view with two lateral elevations, in lateral view with contour not foot-shaped ( Figs 25, 26 )........................... M. nordestina sp. nov.

4. Mesepimeron with reddish-brown area restricted to lower 1/5 of sclerite ( Fig. 8 ); contour of penis segment 2 in lateral view with dorsal and ventral margin straight ( Fig. 22 ), apex of inner fold projected ventroapically as a tubercle ( Fig. 22 )........................................................................................... M. kesselringi sp. nov.

4’. Mesepimeron totally reddish-brown ( Fig. 9 ); contour of penis segment 2 in lateral view with dorsal margin undulated and ventral margin with a semicircular elevation at midlength ( Fig. 20 ), apex of inner fold hardly visible, not projected ventroapically ( Fig. 20 ).............................................................................. M. mielkei sp. nov.

Figures

FIGURES 11–16. Atlantic Forest species of Mecistogaster. (11–14) Mecistogaster kesselringi sp. nov., holotype ♁: (11) forew- ing, (12) hindwing; paratype ♀: (13) forewing, (14) hindwing; (15–16) Mecistogaster amalia, first described ♀: (15) forewing, (16) hindwing.

FIGURES 27–28. Male cerci of Atlantic Forest species of Mecistogaster amalia, neotype. (27) cerci in dorsal view, (28) cerci in lateral view.

FIGURES 17–18. Male genital fossa of Atlantic Forest species of Mecistogaster. (17) anterior hamuli with alula, (18) anterior hamuli without alula. The alula is indicated with a black arrow.

FIGURES 8–10. Males of Atlantic Forest species of Mecistogaster. (8) Mecistogaster kesselringi sp. nov., paratype: pterothorax in lateral view; (9) Mecistogaster amalia, neotype: pterothorax in lateral view; (10) Mecistogaster amalia, presumed type in Halle Museum: pterothorax in lateral view.

FIGURES 23–26. Males of Atlantic Forest species of Mecistogaster. (23–24) Mecistogaster amalia, specimen compared with neotype: (23) penis in ectal view, (24) penis in lateral view [part of flagellum cut to fit the image]; (25–26) Mecistogaster nordestina sp. nov., holotype: (25) penis in ectal view, (26) penis in lateral view [part of flagellum cut to fit the image].

FIGURES 19–22. Males of Atlantic Forest species of Mecistogaster. (19–20) Mecistogaster mielkei sp. nov., paratype: (19) penis in ectal view, (20) penis in lateral view [with flagellum broken]; (21–22) Mecistogaster kesselringi sp. nov., paratype: (21) penis in ectal view, (22) penis in lateral view [part of flagellum cut to fit the image].