Tetheamyrma

A monotypic genus known from a few specimens of Tetheamyrma subspongia collected from litter samples.

Identification
Tetheamyrma belongs in the Rogeria-Stenamma-group of genera, based on the structure of the mandibles and clypeus, and the form of the alitrunk. It is isolated among these, however, by its combination of 11-segmented antennae with a 2-segmented club, and the presence of spongiform material on the waist and gaster. (Bolton 1991)

Distribution
Sabah, Malayasia.

Species richness
Species richness by country based on regional taxon lists (countries with darker colours are more species-rich). View Data



Biology
Spongiform material on the waist segments and base of the gaster ventrally was previously known only in the tribe Dacetini and the non-dacetine genus Dacetinops. Tetheamyrma is not related to either of these and thus represents a third independent evolution of this feature, whose function remains unknown.

Castes
Known only from the worker caste.

Nomenclature

 *  TETHEAMYRMA [Myrmicinae: Stenammini]
 * Tetheamyrma Bolton, 1991: 9. Type-species: Tetheamyrma subspongia, by original designation.

Diagnosis of worker. Monomorphic terrestrial (leaf litter) myrmicine ants with the following combination of characters.

1. Palp formula 2, 2 (in situ count).

2. Mandible triangular, with 6 teeth, the two basal teeth poorly defined.

3. Anterior clypeal margin lacking an isolated median seta, instead with a pair of setae that straddle the midpoint.

4. Median portion of clypeus narrow posteriorly, narrowly inserted between the frontal lobes.

5. Median portion of clypeus narrowly bicarinate, the carinae arising between the frontal lobes and diverging anteriorly.

6. Frontal lobes broad, each lobe considerably broader than the portion of the clypeus that is inserted between them.

7. Torulus concealed by frontal lobes in full-face view.

8. Frontal carinae and antennal scrobes absent.

9. Small eyes present, situated just in front of the midlength of the sides.

10. Antennae II-segmented, with a strongly defined 2-segmented apical club.

11. Alitrunk short and compact in profile; promesonotum forming a single even convexity; metanotal groove impressed; propodeal dorsum steeply sloping posteriorly.

12. Propodeum with a pair of short triangular spines which are connected to the narrow rounded metapleural lobes by narrow infradental lamellae.

13. Propodeal spiracle conspicuous, low on side and behind midlength of sclerite.

14. Tibial spurs absent from middle and hind legs.

15. Petiole with a short stout anterior peduncle and with a relatively large anteroventral process; petiolar spiracle located at the node.

16. Petiole ventrally (behind the process) and postpetiole ventrally with a clump of loose spongiform material which appears to be composed of densely interwoven or fused pilosity; base of first gastral sternite with a pad of similar spongiform material.

17. Sting functional, simple.

18. Cuticle thick and densely sculptured; pilosity fine and dense everywhere.

Additional References

 * [[Media:Bolton 1991.pdf|Bolton, B. 1991. New myrmicine genera from the Oriental Region (Hymenoptera: Formicidae). Syst. Entomol. 16: 1-13 PDF]]