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Genus Pasimachus

unknown beetle - Pasimachus beetle with huge pincers - Pasimachus strenuus Pasimachus sublaevis ? - Pasimachus sublaevis beetle - Pasimachus black beetle - Pasimachus sublaevis Pasimachus Pasimachus Beetle - Pasimachus Pasimachus elongatus - male - female
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Adephaga (Ground and Water Beetles)
Family Carabidae (Ground Beetles)
Subfamily Scaritinae
Tribe Pasimachini
Genus Pasimachus
Other Common Names
Pedunculate Ground Beetle, Blue-margined Ground Beetle (P. elongatus), Fierce Ground Beetle (P. depressus)
Pronunciation
pā-sim'a-kus(1)
Explanation of Names
Pasimachus Bonelli 1813
'total fighter'
Numbers
11 spp. in 3 species-groups (all in the nominotypical subgenus) in our area, 32 spp. in 4 subgenera total(2)
Size
21-40 mm
Identification
Large, extra-robust, flightless ground beetles (elytra fused into rigid shell). Huge jaws, head, pronotum. Some have blue margins. Typically run about under or on leaf litter in forests.
keys to spp. in(3)(4)(5)(6)(7)

The best key to North American species of Pasimachus is by Purrington & Drake (2005)(3). A common identification difficulty is sympatric Pasimachus "depressus" vs "elongatus". The dorsal habitus is much more robust/broad in "depressus", most with body length ≥ 28 mm vs ≤ 26 mm for most "elongatus". The most reliable external separator is the shape of the prosternal process (conical vs roundish) as described in the key. In "depressus", the male metatibia (distal third) bears no golden tuft of hairs, but present so in male "elongatus".
Range
North and Middle America; in our area, most diverse in the south, with just one sp. (P. elongatus) reaching Canada (MB-AB)(2)
Food
caterpillars, other larval insects
See Also
Stag Beetles (Lucanidae) (easily distinguished by their geniculate clubbed antennae)