Key to the Anochetus species of the Neotropics

This worker key is based on: Brown, W. L., Jr. 1978. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography. Studia Entomologica. 20:549-638.

This key is slightly outdated but is the best available for the genus.

Feitosa & Delabie (2012) - Anochetus was treated globally by Brown (1978). In the Neotropical Region, it is represented by 24 extant species with ranges from tropical Mexico, east into some Caribbean Islands, to northern Argentina (Fernandez & Sendoya 2004; Bolton et al. 2006). Ants of this genus may nest and forage in different habitats. Most species nest in the ground or in rotten wood and often can be found foraging well above ground level on forest or savanna tree trunks, generally after dark. Other species nest in the soil of arid areas, and forage over the ground surface near midday in only scanty shade (Brown 1978; Lattke 2003; Fernandez 2007). Furthermore, some species appear to be exclusively arboreal nesters and foragers, although direct observations are very rare in this habitat (Brown 1978; Delabie et al. 2003; Longino 2007).

Since Brown’s revision (1978), eleven additional Neotropical species have been described: eight fossils species from Dominican Amber (Anochetus ambiguus, Anochetus brevidentatus, Anochetus conisquamis, Anochetus corayi, Anochetus dubius, Anochetus exstinctus, Anochetus intermedius, Anochetus lucidus); two species from the mountains west of Cali, Colombia (Anochetus elegans, Anochetus vallensis); another colombian species (Anochetus chocoensis), an arborean Brazilian species (Anochetus hohenbergiae) and a species associated with leaf-cutter ants in Paraguay and Argentina (Anochetus miserabilis).

Comparatively, species of Anochetus are usually smaller than those of the close relative Odontomachus. However, the description of A. elegans by Lattke (1986) modified the concept of the genus and blurred the size limits between Anochetus and Odontomachus. In fact, until this moment, A. elegans was the largest species known for the genus (worker total length 12.24–12.51 mm).

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Anochetus

1

 * Large species with long mandibles, combined L of head and closed mandibles (HL + ML) > 2.2. mm; medial borders of mandibles with 2 or more prominent, serially arranged teeth (in addition to the 3 teeth at apex) . . . . . 2


 * Species either with HL + ML < 2.2. mm, or else medial borders of mandibles without prominent teeth proximal to the single pre apical tooth or angle . . . . . 10

2
return to couplet #1
 * Mandibles with > 10 preapical teeth and denticles . . . . . 3


 * Mandibles with < 10 preapical teeth and denticles . . . . . 6

3
return to couplet #2
 * Petiolar node low, the anterior slope as seen from side view rising at an angle of only about 30° to the main axis of the petiole; petiolar apex forming a blunt double point that strongly overhangs the receding posterior face of the node; first gastric segment (postpetiole) bell-shaped as seen from the side or from above, both dorsal and ventral faces concave in outline for much of their lengths, but the segment abruptly and strongly constricted just before its caudal margin (N Peru; Maranoo Valley, ca. 1500 m) . . . . . Anochetus inca


 * Petiotar node high. main anterior slope rising at an angle of ca. 45°; petiolar apex more or less acutely double-pointed, the points directed dorsad, and not overhanging posterior face of node, which is vertical and usually convex as seen from the side ; first gastric segment evenly convex above and laterally as seen from the side or from above, ventral surface straight or nearly so; caudal margin only slightly and gradually constricted . . . . . 4

4
return to couplet #3
 * Smaller species (HL + ML < 2.80 mm); pronotum very finely and densely punctate, opaque, without striation (SE Brasil: N Espirito Santo) . . . . . Anochetus oriens


 * Larger species (HL + ML > 2.80 mm); pronotum with fine or coarse striation, or its disc sometimes partly or largely smooth and shining (emarginatus superspecies) . . . . . 5

5
return to couplet #4
 * Yellow, trunk ferruginous yellow; most of vertex, disc of pronotum and upper front half of petiolar node smooth and shining; petiolar teeth short and not very sharp (W. Indies: St. Vincent, Grenada) . . . . . Anochetus testaceus


 * Trunk, petiole and node ferruginous to piceous, head and legs paler, yellowish; pronotum varying from transversely rugose or striate to largely smooth and shining, but upper front face of petiolar node usually rugulose and opaque; petiolar teeth short (Amazon Basin N to N. Colombia .. Trinidad) . . . . . Anochetus emarginatus


 * Body dark reddish-brown, including head (corners of head slightly paler), legs brownish-yellow ; frontal area, front and sides of pronotal disc, and upper front face of petiolar node finely striolate, sericeous; posterior center of pronotal disc smooth and shining; petiolar teeth long (L 0.1 mm or more) and sharp (Costa Rica: Atlantic lowlands) . . . . . Anochetus striatulus


 * Body light ferruginous; pronotum striate at least over front half; sculpture and petiolar teeth varying with locality (locally in C. America, Bahamas, see discussion) . . . . . Anochetus micans

6
return to couplet #2
 * Mesial borders of mandibles each with 7-9 teeth and denticles (excluding apical trio; W. Indies) (haytianus superspecies) . . . . . 7


 * Mesial borders of mandibles each with 3-5 teeth and denticles (excluding apical trio; Amazon-Orinoco Basins) . . . . . 9

7
return to couplet #6
 * Propodeal teeth small but well developed, acute, erect (Puerto Rico, inCluding Culebra I.) . . . . . Anochetus kempfi


 * Propodeal teeth absent, or at most low, inconspicuous and obtuse ,(Hispaniola) . . . . . 8

8
return to couplet #7
 * Mandibles longer, MI > 61; paired teeth of petiolar apex very long (L > 0.2 mm) and slender (Haiti: La Hotte Massif, 1000+ m) . . . . . Anochetus longispinus


 * Mandibles shorter, MI < 61; petiolar teeth shorter, L not over 0.1-5 mm (E Central Haiti) . . . . . Anochetus haytianus

9
return to couplet #6
 * Mandibles nearly as long as hood, MI > 85; 3 of the teeth on each inner preapical mandibular border large and spiniform when unbroken (Brasil: Para, Amazonas) . . . . . Anochetus horridus


 * Mandibles shorter, MI < 80; 2 of the teeth on each inner preapicat mandibular border large and spiniform when unbroken (Brasil: NE Mato Grosso) . . . . . Anochetus vexator

10
return to couplet #1
 * Petiolar node as seen from front or rear with apical margin rounded, slightly flattened, or very weakly emarginate in the middle, but in this case, the free corners are always broadly rounded . . . . . altisquamis group . . . . . 11


 * Petioiar node as seen from front or rear with apical margin distinctly concave, the 2 free corners forming angles or produced as teeth . . . . . 12

11
return to couplet #10
 * Pronotum smooth only in the middle of the disc, its sides siriolate and scarcely shining; size larger, HW > 1.3 mm; vertex mostly striolate and vaguely roughened, with inconspicuous punctulae in the narrow posterior smoother zone (S Brasil, N Argentina) . . . . . Anochetus altisquamis


 * Pronotum smooth and shining on disc and sides, with spaced punctures; HW < 1.3 mm; vertex mostly smooth and shining, thickly sown with separate, conspicuous punctures (SE Mexico) . . . . . Anochetus orchidicola

12
return to couplet #10
 * Small species, combined length of head and closed mandibles (HL + ML) < 1.75 mm second segment of antennal funiculus less than twice as long as broad . . . . . mayri complex; see discussion . . . . . 13


 * Larger species, HL + ML > 1.75 mm; second segment of antennal funiculus at least twice as long as broad . . . . . 14


 * Some specimens in the intermediate size range, HL + ML 1.60-1.75 mm, may possibly belong in couplet 14. (coastal mts. of SE Brasil) . . . . . problem specimens, inermis group

13
return to couplet #12
 * Head and trunk very finely striolate, sericeous-opaque (pronotum sometimes densely punctulate rather than striolate but still opaque), mesopleura completely sculptured; eyes usually 0.13-0.16 mm in greatest diameter; color usually uniform reddish- or yellowish-brown, rarely somewhat infuscated (SE and C Brasil S to N Central Argentina) . . . . . Anochetus neglectus


 * Sculpture and color variable; head striate for varying distances; pronotum striate or smooth, in part or entirely; eyes usually 0.09-0.13 mm in greatest diameter (S Mexico and W. Indies S through Amazon Basin to Bolivia; W of Andes to S Ecuador) . . . . . Anochetus mayri

14
return to couplet #12
 * Modest-sized species, HW < 1.20 mm; pronotum smooth or variously sculptured, but not coarsely rugose; petiolar teeth undeveloped or shorter, lately longer . . . . . 15


 * Larger species, HW > 1.2 mm; pronotum coarsely reticulate-rugose; petiolar teeth long, acute and strongly diverging (hylean S. America) . . . . . Anochetus bispinosus

15
return to couplet #14
 * Compound eyes < 0.08 mm greatest diameter (Central America) . . . . . Anochetus minans


 * Eyes > 0.08 mm greatest diameter, inermis group; see discussion . . . . . 16

16
return to couplet #15
 * Dorsum of head and most or all of trunk finely and densely punctulate and matt;• pronotum with a single pair of long standing hairs (one or both of which may be missing); color uniform light brownish-yellow .. . . . . . 17


 * Head and trunk with varied sculpture: striate, costulate or rugulose, and partly smooth; pronotum with more than 4 standing hairs; color variable, often variegated . . . . . 18

17
return to couplet #16
 * Inner mandibular borders each with a single margin bearing a series of coarse teeth; teeth at apex of petiolar node strong and acute (N Venezuela, SW to Ecuadoi, in forest) . . . . . Anochetus simoni


 * Inner mandibular borders each with 2 margins; dorsal margin unarmed except for the preapical angle; ventral margin with variably distinct denticles, or unarmed; corners of apical margin of petiole not acutely dentiform (N S. America. Trinidad, sporadic in Lesser Antilles, mainly in savanna or thin woodlands) . . . . . Anochetus inermis

18
return to couplet #16
 * Mesonotum and propodeum with several to many sta nding (mostly inclined) hairs; mandibles only slightly broadened apicad, their ventral inner margins usually unarmed (Hylea to Bolivia) . . . . . Anochetus targionii


 * Mesonotum and propodeum with at most 1 or 2 standing hairs; mandibles broadened apicad, their inner margins with or without low teeth or denticles (N S. America, Panama) . . . . . Anochetus diegensis