Formicidae, Hymenoptera, Insecta, Arthropoda, Animalia
Mexico, Central America, Bolivia (Brown 1976, 1978). Costa Rica: throughout, in wet and dry forest below 700m.
Face to near margin of vertex striate; head length often above 2.8mm; petiolar node as seen from the side gradually tapered dorsad, with basal half to 2/3 of anterior outline concave or straight; first gastral tergite either smooth and shining or finely striate (see below); pubescence on first gastral tergum suberect and relatively uniform, not wooley; color variable, either with light red brown head and mesosoma, or more uniformly dark brown to nearly black.
This species occurs in wet or dry forest habitats throughout the lowlands of Costa Rica. Foragers are usually on the forest floor, and may be diurnal or nocturnal. I often find workers as prey of Eciton. I have never seen a nest.
Odontomachus haematodus var. laticeps Roger 1861:25. Syntype worker: Mexico, Veracruz: Cordoba.
Odontomachus haematodes r. striativentris Emery 1890:44. Syntype worker: Costa Rica: Jimenez. Junior synonym of laticeps: Brown 1976:106.
Brown (1976) states:
O. laticeps comes in two extreme forms, one of which has head, trunk, petiole and appendages dull, light red in color, while the gaster is usually brownish or blackish, with strong bluish reflections, and the first two gastric terga are completely, distinctly, finely and opaquely longitudinally striate over their discal surfaces; this form corresponds to the type of O. striativentris. Most such samples come from the lowland forests on the Atlantic side of Costa Rica. The other extreme is a form with dark reddish brown to piceous forebody and black gaster, the first two terga smooth and shining discad, with scattered fine punctures. This form ranges from upland Costa Rica (and doubtless the mountains of Panama) north in tropical Mexico to southern Tamaulipas; Roger's type of var. laticeps (of haematodus), from Cordoba, Veracruz, can be assigned here with confidence.
The two extreme forms are connected by a series of samples from localities spread from Panama to southern Mexico, showing different combinations and degrees of development of the color and sculptural characters. Here are a few examples:
Costa Rica, Osa Peninsula: 5 km west of Rincon de Osa, 50 m (J. Wagner and J. Kethley), a very dark worker, almost black, with dark brown legs, first 2 gastric terga finely but distinctly striate throughout.
Central Meseta of Costa Rica: San Jose, Cartago, and Agua Caliente (W. M. Wheeler): these samples, while predominantly of the dark, smooth extreme, contain scattered workers having faint, fine striation in the middle of the first tergum, mostly near its posterior border.
[numerous other examples are given from other countries.]
The above samples taken together seem to indicate that we are dealing with a single variable species that tends to have a dark form with smooth gastric dorsum in upland situations, and a light reddish to dark form with striate gaster in wet lowlands, though exceptions occur in both directions.
Material I have collected from localities throughout Costa Rica only confirm the above observations.
Brown, W. L., Jr. 1976. Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section A. Introduction, subtribal characters. Genus Odontomachus. Studia Entomol. 19:67-171.
Brown, W. L., Jr. 1978(1977). A supplement to the world revision of Odontomachus (Hymenoptera: Formicidae). Psyche 83:281-285.
Emery, C. 1890. Studii sulle formiche della fauna neotropica. I-V. Boll. Soc. Entomol. It. 22:38-80.
Roger, J. 1861. Die Ponera-artigen Ameisen (Schluss). Berl. Entomol. Z. 5:1-54.
John T. Longino, The Evergreen State College, Olympia WA 98505 USA.email@example.com
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