Typhlomyrmex

Typhlomyrmex species are cryptobiotic and therefore rarely encoutered ants. They nest and forage in dead tree trunks (T. rogenhoferi) or within the soil (all other species). All species are presumably predaceous, T. meire seems to be a specialized predator of imagos and immature stages of Acropyga ants.
Sebastien Lacau is working on a systematic revision of the genus and kindly helped with the identification of species.

Typhlomyrmex major Santschi 1923

on Hymenoptera Name Server

Measurements
HL 0.56-0.62; HW 0.52-0.56; CI 90-94; SL 0.41-0.42; SI 75-86; (n=2)

Identification
Mandible triangular, with a large apical tooth; scapes do not reach the posterior margin of the head when held straight back; metafemora base sharply swollen ventrally (image of metafemur); petiolar node higher than long with a differentiated posterior face; large & peculiar subpetiolar process.

Natural History:
I have collected this species only once (2 specimens) in a soil sample from an old growth forest.

Typhlomyrmex pusillus (species complex) Emery 1894

on Hymenoptera Name Server

Measurements
HL 0.41; HW 0.30-0.31; CI 74-76, SL 0.25-0.26, SI 79-86, (n=3)

Identification
Mandibles triangular; metafemora base weakly swollen ventrally; petiolar node as high as long with a differentiated posterior face, very small.

Taxonomic Notes
Brown (1965) suggested in his revision of the genus that T. pusillus includes several species. He noted for two samples from Peru and Brazil (Pará) the occurrence of „a small, square to sharply trapezoidal lamellar lobe or process on the median anterior clypeal margin“ which also occurs in specimens from Cachoeira Nature Reserve.

Offline References

Brown, W. L., Jr. (1965): Contributions to a reclassification of the Formicidae. IV. Tribe Typhlomyrmecini (Hymenoptera). Psyche (Camb.) 72:65-78.

Lacau, S., Villemant, C., Delabie J.H.C. (2004): Typhlomyrmex meire, a remarkable new species endemic to Southern Bahia, Brazil (Formicidae: Ectatomminae). Zootaxa 678:1-23.

Lacau, S., Villemant, C., Delabie J.H.C., Jahyny, B. & Ramos, L.S. (2003): Observações preliminares sobre a ecologia nutricional de Typhlomyrmex sp. (Ponerinae: Typhlomyrmecini). Anais do XVI Simpósio de Mirmecologia, UFSC, Florianópolis, Santa Catarina, pp. 342-344.

Online References

Definition of Measurements:

Head length (HL): maximum longitudinal length from the anteriormost portion of the clypeus to the midpoint of a line drawn across the posterior margin of the head from its highest points.
Head width (HW): maximum head width, excluding eyes.
Cephalic Index (CI): HW/HL*100.
Scape length (SL): scape length, not including basal constriction and condyle.
Scape Index (SI): HW/SL*100.

History of Changes:

25/09/2006: changed Typhlomyrmex JHB01 to Typhlomyrmex major
25/09/2006: added image of metafemur of Typhlomyrmex major