Tetheamyrma bidentata

This species was collected in elevations ranging from about 170 to 1300 m a.s.l. It was collected from leaf litter in good secondary and primary forest.

Identification
There are two species in the genus. They can be separated using the following couplet by General and Buenavente (2018):

Tetheamyrma bidentata - Spongiform tissue absent from ventral surfaces of petiole, postpetiole, and first gastral sternite; antenna with 10 segments; frontal carina just reaching level of anterior margin of eye; anteromedian clypeus produced into a bidentate process (Philippines).

Tetheamyrma subspongia - Spongiform tissue present on ventral surfaces of petiole, postpetiole, and first gastral sternite; antenna with 11 segments; frontal carina not reaching level of anterior margin of eye; anteromedian clypeus medially emarginate but not produced into a bidentate process (Malaysia)

Distribution based on Regional Taxon Lists
Indo-Australian Region: Malaysia, Philippines.

Nomenclature

 *  bidentata. Tetheamyrma bidentata General & Buenavente, 2018: 47, figs. 2a-c, 3a-c (w.q.) PHILIPPINES.

Worker
Holotype: (mm): CI 100, EL 0.05, HL 0.41, HW 0.41, ML 0.45, PW 0.26, SI 58, SL 0.24. Paratype: (n = 17, mm) [mean value and range]: CI 96 (87 - 111), EL 0.05 (0.05 - 0.06), HL 0.46 (0.41 - 0.50), HW 0.44 (0.40 - 0.50), ML 0.51 (0.45 - 0.58), PW 0.30 (0.26 - 0.34), SI 57 (50 - 66), SL 0.25 (0.21 - 0.29).

Monomorphic ants. Head densely rugo-reticulate dorsally, laterally, and ventrally, except for smooth genal bridge. Frontal lobes sculptured. Head pilosity composed of stiff decumbent hairs about as long as distance between them. In full-face view, head widest behind eyes, narrowing slightly anteriorly. Posterior margin of head shallowly emarginated. Antennae with 10 segments, with very large 2-segmented club. Antennal scape short, just reaching level of posterior margin of eye, smooth except for piligerous punctures, with short decumbent hairs. Antennomeres 3 to 8 much broader than long. Antennal scrobe absent. Compound eye small, composed of about eight ommatidia, located laterally, entirely forward of midlength of head. Frontal carina short, slightly beyond level of anterior margin of eye. Frontal lobes broad, completely concealing torulus, much wider than posterior clypeus inserted between them. Median clypeus narrowly bicarinate, with carinae starting at posterior clypeus and terminating at the apices of bidentate process. Anterior clypeal margin produced into median bidentate process. Mandible triangular, smooth. Mandibular dentition composed of apical and subapical teeth, a short diastema, third tooth (shorter than subapical tooth), and three to four denticles. Basal external margin of mandible smooth. In lateral view, palp formula 2,2 (undissected). Occipital carina present. Mesosomal outline smoothly convex. Promesonotal suture absent. Metanotal groove very weakly impressed. Mesosoma densely rugo-reticulate dorsally and laterally. Metapleuron and propodeal declivity smooth. Mesosomal pilosity composed of short, erect hairs on dorsum, except for glabrous propodeal declivity. Propodeal declivity steeply sloped. Propodeum with short, acute, triangular spines. Infradental lamella between propodeal spine and metapleural lobe absent. Metapleural lobe low and rounded. Propodeal spiracle circular, somewhat posteriorly directed. Petiole rugo-reticulate dorsally and laterally. Petiole blocky with short peduncle and straight anterior face. Anterodorsal corners of petiole node produced into acute angles. Anteroventral subpetiolar process present. Anteroventral subpetiolar process finely reticulate. Anteroventral subpostpetiolar process present. Anterior face of postpetiole sharply differentiated from dorsal face. Spongiform tissue absent from petiole, postpetiole, and gaster. Spurs absent from mesotibia and metatibia. Sting simple and functional. In dorsal view, mesosoma rugo-reticulate, widest at the pronotal humeri with lateral margins converging posteriad. Propodeal spines slightly divergent. Petiole node transverse, broader than long. Petiole and postpetiole rugo-reticulate. Dorsum of gaster smooth between piliferous scalloped foveae. Foveae diminishing in size posteriorly from anterior third of tergite. Gastral pilosity composed of erect fine hairs slightly longer than distance between them. In ventral view, genal bridge bounded laterally by a longitudinal carina. Sculpture: antennal scape smooth to weakly reticulate; head, mesosoma, petiole, and postpetiole dorsally and laterally reticulate, with smooth interstices; mandibles, metapleuron, propodeal declivity smooth; subpetiolar process finely reticulate; gaster smooth between scalloped foveae that bear long, fine setae; foveae diminishing in size posteriorly from anterior third of tergite. Pilosity: head with short, fine, decumbent, recurved setae arising from interstices of reticulate sculpture; a pair of setae straddle anterior median clypeus; a pair of longer setae extend laterally from lateral margin of head behind eyes; antennal scape with short decumbent hairs; a short, decumbent hair may arise from center of compound eye; mesosoma, except propodeal declivity, with fine, short erect setae; petiole, postpetiole, and gaster with longer fine, erect setae. Color: dark reddish brown with brown appendages.

Queen
(mm): CI 103, EL 0.11, HL 0.50, HW 0.51, ML 0.66, PpH 0.18, PpL 0.13, PpW 0.18, PSL 0.10, PtH 0.18, PtL 0.21, PtW 0.19, PW 0.43, SI 54, SL 0.28.

Larger than worker in all dimensions. In full-face view, head similar to worker except for the presence of ocelli and larger compound eyes. Compound eye with about 50 ommatidia. In lateral view, anterior outline of pronotum precipitous. Dorsal margin of mesosoma moderately flat. Wing scars present. Epimeral sclerite absent. Deep, sinuous suture between posterior margin of pronotum and anterior margin of mesopleuron. Mesopleuron divided by broad, transversely carinate, sulcus. Metanotum dorsally flat, triangular. Propodeal declivity very steep. Propodeal spines triangular. Propodeal spiracle below midlength on sclerite. In dorsal view, mesosoma areolate. Promesonotal suture and metanotal groove impressed. Sculpture, pilosity and color as in worker.

Type Material
Holotype: worker, Philippines: Samar Island, Western Samar, Municipality of Paranas, Barangay San Isidro, Mukalog Creek, N 11° 52' 01.4", E 125° 12' 47.2", 174 meters above sea level (m a.s.l.), 12. - 15.III.2016, leg. P.A.C. Buenavente, (collection code PACB128), PNM13637. Paratypes same data as holotype: 1 worker (collection code PACB157), PNM13627; 4 workers, (collection code PACB131), PNM13628 through PNM13631; 6 workers, (collection code PACB152), PNM13632 through 13636, and PNM13638; Luzon Island, 1 dealate queen, Bataan, Municipality of Samal, Barangay Palili, Sitio Bakyas, site “B”, N 14° 43' 08.3", E 120° 23' 46.4", 836 m a.s.l., 02.II.2015, leg. P.A.C. Buenavente and J. Baroga, (collection code PACB19), PNM10769; 1 worker, Laguna, Mt. Banahaw, Municipality of Majayjay, Barangay Bukal, Sitio Pitonggabi, N 14° 05' 57.3", E 121° 28' 50.2", 793 m a.s.l., 24.III.2015, leg. P.A.C. Buenavente, (collection code PACB102), CASENT0633220, ADMAC DNA voucher, PNM13643; Mindanao Island, 1 worker, Davao Oriental, Municipality of San Isidro, Mt. Hamiguitan, Barangay La Union, Sitio Tumaguite, N 06° 43' 36.6", E 126° 10' 58.8", 1300 m a.s.l., 04. - 06.VII.2016, (D.E.M. General, P.A.C. Buenavente) (collection code PACB165), PNM13642 1 worker and 1 dealate queen, Davao Oriental, Municipality of San Isidro, Mt. Hamiguitan, Barangay La Union, Sitio Tumaguite, N 06° 43' 59.4", E 126° 09' 58.1", 989 m a.s.l., 04. - 06.VII. 2016, leg. D.E.M. General and P.A.C. Buenavente, (collection code PACB169), PNM13641 and (collection code PACB170), PNM13644; 2 workers, Davao Oriental, Municipality of San Isidro, Mt. Hamiguitan, Barangay La Union, Sitio Tumaguite, N 06° 44' 05.1", E 126° 08' 34.1", 396 m a.s.l., 16. - 17.VII.2016, leg. P.A.C. Buenavente, (collection code PACB182), PNM13639 and PNM13640. All specimens are deposited in, with accession numbers that start with “PNM”.

Etymology
The specific epithet refers to the bidentate anterior clypeal margin of this species.