Identification
Species identification is difficult •
habitus photos of 52 spp. occurring in PNW
(3)
Old Key to Nearctic subgenera modified from
(4)
1. Protibial spur trifid ⇒ZEZEA (9 spp.)
Protibial spur simple ⇒2
2. Prosternal process not margined at apex ⇒CURTONOTUS (15)
Prosternal process margined at apex ⇒3
3. Prosternal process apically plurisetose ⇒4
Prosternal process apically asetose, or 2- or 4-setose ⇒5
4. Pronotum with posterolateral impression delimited laterally by a pronounced carina; transcontinental ⇒PERCOSIA (1)
Pronotum with posterolateral carina suggested; OK‒TX ⇒NEOPERCOSIA (1)
5. Pronotum basally ±constricted, sinuate or not in front of hind angles, or very narrow, with dense and pronounced punctation across basal area; dorsum rufopiceous to black, not metallic. ⇒BRADYTUS - fulva group (10)
Pronotum basally broad, sides slightly curved or straight towards hind angles, but not sinuate; dorsal surface dark, dull, to metallic ⇒6
6. Elytron with stria 7 preapically with 4‒5 punctures; California ±BRADYTUS - insignus group (2)
Elytal stria 7 preapically with 0-3 punctures ⇒AMARA s.str. (~40), CELIA (12), PARACELIA (1), AMAROCELIA (12), XENOCELIA (12)
Below is an updated work-in-progress key after Ball & Bousquet 2001; modified/expanded by PW Messer 2024, 2025
Updated Key to the Nearctic subgenera of Amara
Abbreviations. E7:0, E7:1, E7:2, … = 0, 1, 2, … setigerous punctures subapically in elytron stria #7; m/s = microsculpture.
01. Front tibia with apical spur trifid; 9 species => Zezea
–– Front tibia with apical spur simple, not forked => 2
2(1). Prosternum with intercoxal process not margined at apex; E7:1; 15 species => Curtonotus
–-- Prosternum with intercoxal process margined at apex; E7:1 or more => 3
3(2). Prosternum with intercoxal process apically plurisetose (≥ 6) => 4
–– Prosternum with intercoxal process apically asetose, or bi- or quadri-setose => 5
4(3). Pronotum with posterolateral impression delimited laterally by a pronounced carina; geographical range
Transcontinental. 1 species (A. obesa) => Percosia
–– Pronotum with posterolateral carina suggested, only; geographical range, Texas only. 1 species (A. fortis) => Neopercosia
5(4). Pronotum basally more or less constricted, sinuate or not anteriad posterolateral angles, or very narrow, with dense and pronounced punctation over entire basal area; dorsal surface dark (rufopiceous to black), dull or shiny, not metallic; E7:1 except for insignis group with E7:4–5. 12 species. => Bradytus
–– Pronotum basally broad, lateral margins slightly curved, straight or slightly sinuate anteriad posterolateral angles; dorsal surface dark, dull, to metallic => 6
6(5). E7:4–5; male prosternum centrally with small impunctate fovea; geographical range, California. 2
species => Bradytus insignis species group
–– E7:0 or E7:2–3 => 7
7(6). Six subgenera below. Most require male structures for secure recognition. The males are distinguished externally by the presence of vestiture scales beneath their relatively expanded segments of the protarsi.
Xenocelia [Hieke 2001:71]: Male with 2 pairs anal setae (subapical abdomen); male prosternum modified centrally (punctate fovea); dorsum not metallic; antenna not strongly bicolored, yellowish but often from 2 or 3 slightly darker, never black; appendages often dark; pronotum never cordate; pronotum with isodiametric m/s; elytral m/s distinctly isodiametric; E striae fine, seldom finely punctulate, never deepen apically; 7th str w 2 punc; male metatibia often with brush. 11 species.
Reductocelia: Pronotum very narrow; E7:1–2; aedeagal right paramere with strong apical hook; 1 species (A. colvillensis in far northwestern North America; see Lindroth 1968: 687).
Celia: Male prosternum not modified (except in A. californica); male metatibia without brush; pronotum with m/s absent, obsolete, or transverse, not isodiametric (except in A. californica). 13 species.
Amarocelia: Essentially like Amara s. str. except for no metatibial brush in males; [male prosternum not modified; elytral striae not deepened apically & without scutellar puncture]. 12 species.
Amara sensu stricto: Metallic dorsum in most species; most with palps & at least femur dark (except A. familiaris and A. anthobia); antennae strongly bicolored; male metatibia with linear brush on inside surface (difficult to see without best viewing angle); E7:2–3; 28 species among three subgroups below.
----impuncticollis group = Elytron with scutellar setigerous puncture; E7:3; antennomeres 1–3 much lighter. 6 species.
----cupreolata group = very metallic; elytron without scutellar puncture; E7:2; only basal antennomere light; pronotum with front angles strongly projected forward; 5 species.
----incertae sedis = the remaining 17 species.
Paracelia: Prosternal intercoxa with 2 setae; eyes flat. 1 species (A. q. quenselli, see Lindroth 1968: 694).
