Ilyobius, Enderlein, 1910

Ardila-Camacho, Adrian, Rivera-Gasperín, Sara Lariza, Martins, Caleb Califre & Contreras-Ramos, Atilano, 2021, A reappraisal of the taxonomy of Neotropical Sialidae (Insecta: Megaloptera): with the description of a new genus from Cuba, European Journal of Taxonomy 782, pp. 21-54 : 43-44

Key to world extant species of Ilyobius

(after Liu et al. 2015b)

1. Thorax: Pronotum pale, uniformly orange to reddish brown (fig. 12A) .......................................... 2

‒ Thorax: Pronotum dark, usually black, sometimes with pale markings ( Liu et al. 2015b: fig. 3) ....... 8

2. Head: without posteriorly trifurcate dark marking around compound eyes ( Liu et al. 2015b: fig. 3) ... 3

‒ Head: with posteriorly trifurcate dark markings around compound eyes ( Liu et al. 2015b: fig. 5) ..... 5

3. Head: blackish brown ....................................................................................................................... 4

‒ Head: uniformly orange brown ( Contreras-Ramos 2006: fig.1).......................................................... ....................................................................................... I. ranchograndis ( Contreras-Ramos, 2006)

4. Head: dark orange on median portion of vertex ( Liu et al. 2015b: fig. 3) .......................................... ............................................................................................................. I. flavicollis ( Enderlein, 1910)

‒ Head: completely dark brown, including the median portion of vertex ( Fig. 12A–B ) ...................... .......................................................................................................... Ilyobius nigrocephalus sp. nov.

5. Head: frons without any dark marking ............................................................................................. 6

‒ Head: frons with a pair of ovoid black spots between antennal fossae ( Fig. 9A–B ) .......................... .............................................................................................................. I. bimaculatus (Banks, 1920)

6. Male abdomen: gonocoxite 9 short, ovoid, not directed posterodorsad ( Liu et al. 2015b: fig. 8), male gonocoxites 11 with median processes directed posteriad ( Liu et al. 2015b: fig. 8) ........................ 7

‒ Male abdomen: gonocoxite 9 elongate and strongly directed posterodorsad ( Contreras-Ramos 2008: fig. 10), male gonocoxites 11 with median processes directed ventrad ( Contreras-Ramos 2008: fig. 10) ..................................................................................................... I. flammatus ( Penny, 1981)

7. Forewing: length more than 11.0 mm in males and 12.0 mm in females; male abdomen: gonocoxites 11 with median processes straightly directed posteriad ( Liu et al. 2015a: fig. 14g); female abdomen: fused gonocoxites 8 bluntly prominent posteriad ( Liu et al. 2015a: fig. 15d)..................................... ............................................................................................................... I. mexicanus (Banks, 1901)

‒ Forewing: length less than 9.0 mm in males and 10.0 mm in females; male abdomen: gonocoxites 11 with median processes distinctly curved posteroventrad on distal half ( Liu et al. 2015b: fig. 8); female abdomen: fused gonocoxites 8 strongly narrowed posteriad ( Liu et al. 2015b: fig. 11) ......... ............................................................................................................... I. curvatus Liu et al., 2015b

8. Head: orange with a median black stripe extending from middle of vertex to frons; male abdomen: sternite 9 posteriorly with a long digitiform, median projection and a pair of short lateral projections ( Contreras-Ramos et al. 2005: fig. 3) ............................................................................................... 9

‒ Head: orange with three broad black markings on frons and lateral portions of vertex, but middle of vertex without dark marking ( Contreras-Ramos 2008: fig. 3); male abdomen: sternite 9 posteriorly with a long digitiform, median projection, but without any posterolateral projections ( Liu et al. 2015a: fig. 14b) .............................................................................................. I. chilensis (McLachlan, 1871)

9. Head: with median black stripe anteriorly, not approaching compound eyes ( Contreras-Ramos et al. 2005: fig. 1); female abdomen: gonapophyses 8 posteriorly convex ( Contreras-Ramos et al. 2005: fig. 6) ................................................................................. I. hauseri ( Contreras-Ramos et al., 2005)

‒ Head:with median black stripe anteriorly expanded and approaching compound eyes ( Liu et al. 2015b: fig. 12); female abdomen: gonapophysis 8 posteriorly broadly concave ( Liu et al. 2015b: fig. 14) .. ...................................................................................................................... I. nubilus (Navás, 1933)

Figures

Fig. 12. Holotype male of Ilyobius nigrocephalus sp. nov. A. Head, dorsal view. B. Head, dorso-frontal view. C. Fore- (above) and hindwing (below).

Fig. 9. Holotype female of Ilyobius bimaculatus (Banks, 1920). A. Head, dorsal view. B. Head, dorsofrontal view. C. Fore- (above) and hindwing (below).