Scirtidae, Fleming, 1821

Ruta, Rafał, 2021, Three new genera of large marsh beetles (Coleoptera: Scirtidae) from Valdivian temperate rain forests of southern South America, Zootaxa 5048 (4), pp. 451-485 : 481

A tentative key to genera of South American Scirtidae

1. Hind femora enlarged, saltatorial......................................................................... 2

-. Hind femora of normal size, not saltatorial................................................................. 4

2. Prosternal process wide, tear-shaped, forming flat plate between procoxae; clypeus with produced anterolateral angles...................................................................................... Prionoscirtes Champion

-. Prosternal process very narrow, laminar, forming sharp edge between procoxae; clypeus rectangular, anterolateral angles not produced............................................................................................ 3

3. Coxae separated, trochanters exposed............................................................. Ora Clark

-. Coxae touching along midline, trochanters hidden................................................. Scirtes Illiger

4. Tibiae without carinae, body very narrow, TL/EW 3.8–4.4.................................... Stenocyphon Lawrence

-. Tibiae with paired longitudinal carinae, body wider, TL/EW <2.5, elongate to oval................................. 5

5. Basal portion of elytra 1.6–2.0× wider than basal portion of pronotum, body elongate, TL/EW 1.9–2.5.................. 6

-. Basal portion of elytra as wide as basal portion of pronotum or only 1.3–1.4× wider, body oblong oval, TL/EW.......... 8

6. Body small, TL <3 mm ................................................................................ 7

-. Body large, TL> 9 mm ................................................................. Argelodes gen. nov.

7. Sides of pronotum with outgrowths, known only from Roraima tepui......................... Exagonthus Waterhouse

-. Sides of pronotum without outgrowths, known from Chile....................................... Chilarboreus Ruta

8. Scape enlarged, anterior margin forming sharp, anterior carina, antennomere 3 reduced, very small, sometimes barely visible (antennomeres 4–10 more or less dilated, often serrate to pectinate)....................... Prionocyphon Redtenbacher

-. Scape cylindrical, anterior margin never sharp, antennomere 3 small but easily seen................................ 9

9. Subgenal ridge with buttonhole configuration............................................... Contacyphon Gozis

-. Subgenal ridge without buttonhole configuration........................................................... 10

10. Head with deep subantennal grooves..................................................................... 11

-. Head without or with shallow subantennal grooves.......................................................... 12

11. Mesoventral process wide, as long as width to transverse......................................... Calvariopsis Ruta

-. Mesoventral process elongate, ca. 1.6× longer than its maximum width........................... Mucronotus gen. nov.

12. Large species, TL> 9 mm, body sides subparallel............................................. Solierodes gen. nov.

-. Smaller species, TL<6 mm, body sides usually rounded...................................................... 13

13. Anterolateral angles of pronotum strongly angled, pronotum transversely rectangular; molar region of mandibles without spines................................................................................. Anticyphon Ruta

-. Anterolateral angles of pronotum rounded, pronotum trapezoidal with semicircular anterior margin, molar region of mandibles with numerous spines............................................................ Pseudomicrocara Armstrong