Ectatomma costatum

This widespread species has been found mostly in lowland rainforest, within rotten logs and leaf litter, and foraging.

Identification
Lattke (2004) - Frons densely foveolate; clypeus with median area laterally defined by two carinae that extend from anterior margin of frontal lobes to lateral margins of clypeal lamella; occipital lamella usually with sharply angular ends in lateral view. Mesosomal dorsum usually densely foveolate; petiolar node with ventral process usually subquadrate in lateral view, sometimes projecting more anterad than posterad but generally with posterior angle. Dorsum of abdominal segment 4 longitudinally costate, occasionally with elongate foveolae and brief costae, not covering whole tergite.

Distribution
This taxon was described from Myanmar. It is also found in Philippines, Thailand, Brunei Darussalam, Indonesia, Singapore, Malaysia and Borneo.

Nomenclature

 * rugosa. Ponera rugosa Smith, F. 1857a: 66 (q.) BORNEO. [Junior primary homonym of Ponera rugosa Le Guillou, 1842: 318 (now in Diacamma).] Replacement name: wallacei Donisthorpe, 1932c: 447. Combination in Stictoponera: Emery, 1911d: 48.
 *  costata. Ectatomma (Stictoponera) costatum Emery, 1889b: 494 (w.) MYANMAR. Wheeler, G.C. & Wheeler, J. 1976a: 44 (l.); Lattke, 2004: 100 (q.m.). Combination in Stictoponera: Emery, 1900d: 662; in Gnamptogenys: Brown, 1958g: 227. Senior synonym of parva, pinealis, simalurensis, unicolor, wallacei: Brown, 1954h: 7.
 * unicolor. Stictoponera costata var. unicolor Forel, 1901f: 335 (w.) BORNEO. Junior synonym of costata: Brown, 1954h: 7.
 * parva. Stictoponera rugosa r. parva Forel, 1913k: 6 (w.) INDONESIA (Sumatra). Junior synonym of costata: Brown, 1954h: 7.
 * simalurensis. Stictoponera costata st. simalurensis Forel, 1915a: 23 (w.) INDONESIA (Sumatra). Junior synonym of costata: Brown, 1954h: 7.
 * pinealis. Stictoponera costata var. pinealis Wheeler, W.M. 1929g: 31 (q.) WEST MALAYSIA. Junior synonym of costata: Brown, 1954h: 7.
 * wallacei. Stictoponera wallacei Donisthorpe, 1932c: 447. Replacement name for Ponera rugosa Smith, F. 1857a: 66. [Junior primary homonym of Ponera rugosa Le Guillou, 1842: 318.] Junior synonym of costata: Brown, 1954h: 7.

Lattke (2004) - Brown (1954b:9) provided an excellent account of the variability of this species and his justification for the many synonymies. He treats the differences in color, size, and sculpturing on postpetiole. While the mesosomal dorsum is usually densely foveolate, specimens with mostly smooth sculpturing and scattered foveolae/punctae will show up, occasionally from Sulawesi. These specimens also tend to have some oblique strigulae on the sides of the fourth abdominal tergite. Even though Brown (1954b) alluded to the variability of the shape of the occipital lamella (which he calls ears or lobes) there does seem to be a large degree of constancy in the angular shape of the two ends of the lamella. Only rarely is one end convex, and no cases were observed in which both ends are convex.

Gnamptogenys toronates may be confused with G. costata, but G. toronates has the propodeal spiracle farther away from the propodeal dorsum when seen laterally, the declivitous and dorsal propodeal margins are separated anterad of the denticle, and the subpetiolar process forms an anteriorly projecting sharp lobe. In G. costata the denticles are between the two propodeal margins.

Worker
Lattke (2004) - Metrics (n = 12): HL 1.24-2.11, HW 1.03-1.64, ML 0.61-1.05, SL 1.05-1.88, ED 0.23-0.40, WL 1.67-3.00 mm. CI 0.78-0.90, SI 0.96-1.21, MI 0.56-0.64, OI 0.20-0.27. Head with mostly straight lateral margins in frontal view, posterior margin straight, occipital lobes posterolaterally projecting; clypeal lamella narrow, its anterior margin with slightly projecting median blunt angle, sides bluntly angular; frons densely foveolate, foveolae forming posteriorly diverging rows with costae between them; gena longitudinally strigate; clypeus with median area laterally defined by two carinae that extend from anterior margin of frontal lobes to lateral margins of clypeal lamella; scape mostly smooth to mostly strigulose; occipital lamella usually with sharply angular ends in lateral view. Lateral pronotal face foveolate, foveolae denser anterad than posterad, humeral angles with convex lamella; mesopleuron foveolate; anepisterum subrectangular; metapleuron smooth to longitudinally costate posterodorsally and foveolate anterodorsally; mesosomal dorsum usually densely foveolate, transverse impressions usually obsolescent; propodeal declivity mostly smooth, depressed with posteromedian raised area, denticles small, occasionally absent.

Petiolar node with ventral process usually subquadrate in lateral view, sometimes projecting more anterad than posterad but generally with posterior angle; petiolar dorsum with transversely ovaloid foveolae, sometimes with transverse strigulae; postpetiolar dorsum varies from foveolate on smooth cuticle to longitudinally strigulose-foveolate, anterior foveolae usually round, becoming progressively more elongate posterad and forming irregular sulci along posterior margin, posterior margin usually with median costulate depression; postpetiolar sternum medially smooth with series of fine transverse strigae anterad, laterally foveolate to foveolate rugulose, with narrow posterior face; dorsum of abdominal segment 4 longitudinally costate, occasionally with elongate foveolae and brief costae, not covering whole tergite. Fore coxa transversely strigulose in lateral view; fore tarsus opposite strigil with row of stout setae, sometimes with single very stout basal seta followed apically by row of less stout setae. Dorsum of thorax and abdominal segments 1-4 with scattered erect to subdecumbent hairs. Head, mesosoma, petiole, and gaster brown to very dark brown, occasionally almost black; mandibles, antennae, legs slightly lighter colored than rest of body.

Queen
Lattke (2004) - Metrics (n = 1): HL 1.76, HW 1.40, ML 0.90, SL 1.36, ED 0.35, WL 2.68 mm. CI 0.80, SI 0.97, MI 0.64, OI 0.25. Pronotum densely foveolate with smooth strip along posterior margin in lateral view; anepisternum rugulose-punctate; katepisternum foveolate with smooth cuticle between depressions, some strigulae present along posterior margin; mesonotum longitudinally rugulose-punctate; metapleuron foveolate; propodeum laterally densely foveolate.

Male
Lattke (2004) - Metrics (n = 1): HL 1.17, HW 1.00, ML 0.57, SL 0.32, ED 0.40, WL 2.07 mm. CI 0.86, SI 0.32, MI 0.57, OI 0.40. Frons with dense, shallow areolae; with carina extending from posteromedian margin of clypeus to mid point of compound eye; clypeus prominent, longitudinally strigulose, surrounded by sulcus; anterior clypeal margin evenly convex. Pronotum laterally with dense foveolae; mesopleuron mostly smooth with scattered punctae; mesoscutum foveolate, metanotum rugulosefoveolate; propodeum laterally areolate, propodeal denticles form small blunt lobes. Petiolar node with irregular foveolae and punctae; postpetiole with shallow foveolae laterally, dorsomedially undulate; fourth abdominal tergite mostly smooth, with scattered shallow punctae.

Type Material
Lattke (2004) - Holotype worker by monotypy: Burma [Myanmar], Tenasserim (Fea) (MCSN) [Examined].

Stictoponera costata var. unicolor Forel, 1901b:335. Syntype workers, queen: Borneo (MHNG) [Not examined]. Synonymy by Brown, 1954b:7.

Stictoponera rugosa var. parva Forel, 1913:6. Holotype worker by monotypy: Sumatra (MHNG) [Not examined]. Synonymy by Brown, 1954b:7.

Stictoponera costata var. simalurensis Forel, 1915:23. Holotype worker by monotypy: Sumatra (MHNG) [Not examined]. Synonymy by Brown, 1954b:7.

Stictoponera costata var. pinealis Wheeler, W.M. 1929:31. Holotype queen by monotypy: Malaysia, Penang (Silvestri) (MCZC) [Examined]. Synonymy by Brown, 1954b:7.

Stictoponera wallacei Donisthorpe, 1932:447. Replacement name for Ponera rugosa Smith, F. 1857:66. Synonymy by Brown, 1954b:7.

Additional References

 * [[Media:Brown 1954h.pdf|Brown, W. L., Jr. 1954h. A review of the coxalis group of the ant genus Stictoponera Mayr. Breviora 34: 1-10 PDF]]