Corresponding author: Peter W. Messer (
Academic editor: T. Erwin
The Mexican carabid species
Using the key and original description by
Other than associations with moist soil and occurrences under stone cover during the day, almost nothing else is known about the natural history of subgenus
All species are now known to inhabit the contiguous United States except for
Previously
I observed marked color variation in large series of specimens that otherwise fit
Previously published (incomplete) keys relied heavily on dorsal color and on the following comparative measurements. Abbreviation L/W is the ratio of length to width of the middle antenna segments (5th or 6th antennomeres). Care is taken to view the broadest aspect of each segment. The ratio E/T is the longitudinal diameter of eye to the length of the posterior temple before the neck constriction, best observed from above. The characteristic values assigned to these ratios are approximations which are usually appreciated visually without exact measurements. Minor adjustments of the published values were made in some cases. Apparent body length, given in millimeters, is measured from mandible tip to abdominal apex. The known Western Hemisphere range is given for each species. New regional extensions that I observed are superscribed
1 | Dorsum distinctly dull, uniformly dark pinkish brown, finely and very closely punctate; 5.5-6 mm. (FL; Bahamas, Caymans, Dominican Republic2, Cuba) |
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– | Dorsum shiny, rufotestaceous to plain dark brown, more coarsely punctate in most species | 2 |
2 | Antennomeres 4-10 squarish, as long as wide (L/W = 1) | 3 |
– | Antennomeres 4-10 distinctly elongated (L/W > 1) | 4 |
3 | Elytral striae rather irregularly but seriately punctate except apically, the punctures much coarser than those of the intervals; pronotum narrower and basal angles more minutely prominent; dorsum dark (reddish to blackish brown) usually with head and elytral disc darkest; eye prominent (E/T = 2); mostly 4.2-5 mm (southeastern US quadrant: AL, AR, FL, GA, LA, MS, NC2, eastern OK 1, 2, SC, TN2, eastern TX1, VA2; Cuba) |
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– | Elytral striae not evidently seriately punctate, not more coarsely punctate than intervals; pronotum broader, basal angles more broadly prominent; uniformly reddish to dark brown; 5-6 mm. (FL, southeastern TX1; Caymans, Cuba, Dominican Republic2) |
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4 | Body length less than 5 mm; dorsum uniformly rufotestaceous; head small, distinctly narrower than pronotum; eyes rather small and flattish; elytra with striae poorly defined, intervals flat; location in southern California; 4.75 mm. (CA) |
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– | Body length usually at least 5 mm; combination not as above | 5 |
5 | Elytra with posterior sutural dark cloud; middle antennomere ratio L/W = 1.75-2 | 6 |
– | Elytra without dark cloud; middle antennomere ratio L/W various | 8 |
6 | Body length ≥ 6 mm; elytral intervals flat to slightly convex, densely punctate; E/T = 1.5 with temples gently curved; middle antennomeres with L/W = 2; dark sutural cloud distinct against rufotestaceous dorsum; 6-7 mm.(southwestern US quadrant: AZ, CA, NM, NV, OK2, TX; Mexico1) |
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– | Body length ≤ 6 mm; elytral intervals distinctly convex, sparsely and finely punctate; middle antennomeres with L/W = 1.75; sutural cloud often less distinct | 7 |
7 | Body length usually ≤ 5.5 mm; eyes larger; temples strongly curved, shorter than in |
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– | Body length 5.6-6 mm; eyes smaller; temples gently curved, longer against small eyes as compared to |
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8 | Body length ≥ 6 mm; middle antennomere ratio L/W = 2; see also key step #6 | |
– | Body length ≤ 6 mm except for |
9 |
9 | Middle antennomeres markedly prolonged with L/W = 3; eye size and convexity both markedly reduced; eye diameter distinctly shorter than temple (E/T < 1); head black, contrasts with dark red-brown dorsum; punctures on forebody coarse and quite dense; elytra stretched lengthwise, slightly oval, not strongly narrowed at shoulders; 6.5-7 mm. (TX - Live Oak Co. is new US record1; Mexico) |
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– | Middle antennomeres short with L/W ≤ 1.75; eyes larger with E/T ≥ 1; head not black; body length less than 6.5 mm | 10 |
10 | Eyes appear markedly enlarged against very short temples (E/T = 3); middle antennomeres shorter (L/W = 1.25); yellow-brown; 4.8-5.1 mm. (Mexico) |
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– | Eyes relatively smaller (E/T < 2); middle antennomeres longer; body usually larger | 11 |
11 | Dorsum uniformly ferruginous (reddish); eyes appear flatter and smaller against long temples (E/T = 1); middle antennomeres L/W = 1.5; 5.1 - 5.5 mm. (western US: AZ1, 2, CA, OR, TX) |
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– | Dorsum not uniformly reddish, often darker brownish; eyes larger relative to temples; middle antennomeres L/W = 1.75 | 12 |
12 | Body length usually ≤ 5.5 mm; eyes relatively large with temples shorter, strongly curved (E/T = 1.5-1.9); see also key step #7 |
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– | Body length 5.6-6 mm; eyes relatively small with temples longer, gently curved (E/T = 1-1.5); see also key step #7 |
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I thank Byron L. Buchli (Deerfield, Wisconsin) for capturing and providing the two specimens reported here. At least one voucher will be deposited in the Insect Research Collection at the University of Wisconsin – Madison. Helpful were Edward G. Riley (Texas A&M University), Terry L. Erwin (Smithsonian Institution National Museum of Natural History), and Susan S. Borkin (Milwaukee Public Museum) who lent