Cyrnellus, Banks, 1913

Rueda Martín, Paola A., Gibon, Francois-Marie & Sganga, Julieta V., 2021, New species and records of the Neotropical genus Cyrnellus (Trichoptera: Polycentropodidae) and the re-establishment of C. minimus and C. marginalis, Zootaxa 5082 (1), pp. 15-29 : 27-28

Key to adult males of the genus Cyrnellus

1. Subapicomesal spine I of each inferior appendage directed obliquely apicad with respect to longitudinal axis of inferior appendage ( Fig. 6B)......................................................................................... 2

- Subapicomesal spine I directed perpendicularly to longitudinal axis of each inferior appendage ( Fig. 3F)............... 4

2(1). Posterior margins of sternite IX convex and sinuous with slight undulations; subapicomesal spine I closer to apex of each inferior appendage and digitate ( Figs 6A–6D, as).................................................... C. misionensis

- Posterior margins of sternite IX irregular with some excisions and protuberances ( Fig. 5A); subapicomesal spine I of each inferior appendage in mesal or subapical position ( Fig. 5B, as)................................................. 3

3(2). Subapicomesal spine I of each inferior appendage mesally inserted, long and digitate ( Figs 4E–4H).............. C. rianus

- Subapicomesal spine I, subapically inserted, short and triangular ( Figs 5A–5D)................................ C. risi

4(1). Subapicomesal spine of each inferior appendage triangular, acute ( Figs 3F, 3I–3K)................................. 5

- Subapicomesal spine rounded or mammiform ( Figs 2F, 6F), or with two subapicomesal points ( Figs 1B, 2B, 5F, 7B)...... 9

5(4). Subapicomesal spine of each inferior appendage arising far from apex ( Figs 3E–3K)...................... C. fraternus

- Subapicomesal spine arising close to apex ( Figs 1G, 3B, 4B)................................................... 6

6(5). Triangular subapicomesal spine of each inferior appendage flat ( Figs 1F–1I)............................ C. boliviensis

- Triangular subapicomesal spine circular in cross-section ( Figs 3B, 4B).......................................... 7

7(6). Subapicomesal spine of each inferior appendage with wide base, forming equilateral triangle ( Figs 3A–3D)... C. marginalis

- Subapicomesal spine with narrow base, forming isosceles triangle ( Fig. 4B)....................................... 8

8(7). Subapicomesal spine of each inferior appendage conspicuously subapical, inner lobe triangular ( Figs 4A–4D).... C. minimus

- Subapicomesal spine very near apex, inner lobe round ( Chamorro-Lacayo 2003, fig. 2B)................ C. zapateriensis

9(4). Subapicomesal spine II of each inferior appendage absent, single subapicomesal spine with wide, globular base ( Figs 2F, 6F) .................................................................................................. 10

- Subapicomesal spines I & II present ( Figs 1B, 2B, 5F, 7B).................................................... 11

10(9). Posterior arms of dorsal phallic sclerite slender, sinuous, and divergent ( Figs 2E–2H)................... C. mammillatus

- Posterior arms of dorsal phallic sclerite thick with heavily sclerotized apices ( Figs 6E–6H)................... C. collaris

11(9). Subapicomesal spine I of each inferior appendage very near apex ( Figs 7A–7D)............................ C. bifidus

- Subapicomesal spine I conspicuously preapical, with variable distance between spine and apex of inferior appendage ( Figs 1B, 2B, 5F)............................................................................................ 12

12(11). Dorsal phallic sclerite complex ( Figs 1C–1E), its anterior arms well-developed and with long sclerotized rods projecting anterad ( Figs 1A–1E)............................................................................ C. arotron

- Dorsal phallic sclerite simple or indistinct ( Figs 2C, 5H), with anterior arms reduced or absent...................... 13

13(12). Subapicomesal spines of each inferior appendage flat ( Fig. 2B); dorsal phallic sclerite with anterior arm reduced, posterior arms divergent, short, and thick ( Figs 2A–2D)......................................................... C. guyanensis

- Subapicomesal spines circular in cross-section ( Fig. 5F); phallic dorsal sclerite indistinct, without anterior arm, posterior arms fused into tube ( Figs 5E–5H)...................................................................... C. ulmeri