Ommatius costatus, Rondani, 1850

Vieira, Rodrigo, Castro, Ivan & Bravo, Freddy, 2005, A new species of Ommatius Wiedemann (Diptera: Asilidae) from Brazil, Zootaxa 1017 (1), pp. 19-24 : 20-21

Key to the Neotropical costatus species group males

1. Margin of scutellum without bristles ........................................ O. achaetus Scarbrough

­ Margin of scutellum with two or more bristles ............................................................ 2

2. Internal margin of epandrium with projection .............................................................. 3

­ Internal margin of epandrium without projection ........................................................ 9

3. Gonostylus wide in lateral view ................................................................................... 4

­ Gonostylus narrow in lateral view ................................................................................ 6

4. Apex of epandrium forked; hypandrium subtruncate ................ O. orenoquensis Bigot

­ Apex of epandrium acute; hypandrium triangular or rhombus like.............................. 5

5 Hypandrium triangular ...................................................................... O. oreophilus Farr

­ Hypandrium rhombus­like ....................................................... O.humatus Scarbrough

6. Posterior margin of epandrium acute ........................................................................... 7

­ Posterior margin of epandrium rounded ....................................................................... 8

7. Hind tibia with spine­like apical bristle ....... O. serrajiboiensis Vieira, Castro & Bravo

­ Hind tibia without spine­like apical bristle ............ O. cinthiae Vieira, Castro & Bravo

8. Ventral lamella with narrow membranous area medially ................... O. amula Curran

­ Ventral lamella without narrow membranous area medially...... O. uncatus Scarbrough

9. Width of aedeagal apodeme, in lateral view, greater than or equal to aedeagal sheath. ..................................................................................................................................... 10

­ Width of aedeagal apodeme, in lateral view, smaller than aedeagal sheath................ 12

10. Gonostylus narrow in lateral view ..................................... O. complanatus Scarbrough

­ Gonostylus wide in lateral view .................................................................................. 11

11. Hind tibia without spur­like apical bristle; aedeagal sheath with projection in the middle section of the basal margin ................................................. O. dentatus Scarbrough

­ Hind tibia with spur­like apical bristle; aedeagal sheath with anterior projection in the basal margin .............................................................................. O. spinosus Sacrbrough

12. Anterior margin of aedeagal sheath with projection .................................................. 13

­ Anterior margin of aedeagal sheath without projection ............................................. 14

13. Hind tibia with spur­like apical bristle .................................... O. piliferous Scarbrough

­ Hind tibia without spur­like apical bristle ................................ O. didymus Scarbrough

14. Aedeagal apodeme, in lateral view, slightly larger than aedeagal sheath ...................... ........................................................................................................... O. alexanderi Farr

­ Aedeagal apodeme, in lateral view, at least twice as large as aedeagal sheath........... 15

15. Dorsal margin of aedeagal sheath, in lateral view, having acute projection .................. ............................................................................................... O. incurvatus Scarbrough

­ Dorsal margin of aedeagal sheath, in lateral view, without acute projection ……..… 16

16. Aedeagal sheath triangular in lateral view; epandrium with short inner apical projection in ventral view ......................................................................... O. costatus Rondani

­ Aedeagal sheath trapezium in lateral view; epandrium with long inner apical projection in ventral view ................................................................................ O. riali , sp. nov.