Myopias sakaeratensis, Jaitrong & Tasen & Guénard, 2018

Jaitrong, Weeyawat, Tasen, Wattanachai & Guénard, Benoit, 2018, The ant genus Myopias Roger, 1861 (Hymenoptera: Formicidae: Ponerinae) in Thailand, with descriptions of three new species, Zootaxa 4526 (2), pp. 151-174 : 166-168

Myopias sakaeratensis sp. nov.

( Figs. 34–36 )

Etymology. The specific name is after the type locality, Sakaerat Environmental Research Station, Nakhon Ratchasima Province, northeastern Thailand.

Type. Holotype worker (THNHM-I-0 0 291, THNHM), NE Thailand, Nakhon Ratchasima Prov., Wang Nam Kheao Dist., Sakaerat Environmental Research Station ( ERS), Dry evergreen forest, 14.51013900°N, 101.95238900°E, 270 m a.s.l., 7.V.2002, D. Wiwatawitaya leg., colony no. WJT 070502 -1. Two paratype workers (THNHM-I-0 0 292 to THNHM-I-00293), same data as holotype ( THNHM); 1 paratype worker (THNHM-I- 00294), NE Thailand, Nakhon Ratchasima Prov., Sakaerat Environmental Research Station , 12.V.2002, C. Bourmas leg. ( THNHM).

Non-type material examined. THAILAND: one worker, NE Thailand, Chaiyaphum Prov., Phu Kheao , 14.VIII.1998, R. Dickinson leg. (AMK).

Diagnosis of worker. Body 6.55–6.65 mm in total length (medium size). Masticatory margin of mandibles with five teeth, including large basal tooth, large prebasal tooth, minute preapical tooth (denticle), and mediumsized apical tooth; basal margin with an ill-defined protuberance; median clypeal lobe slightly broader than long, subtriangular, widened forward, its anterior margin weakly concave, lateral margin and anterior margin meet so as to form sharp angle; eyes relatively large with 15 ommatidia along the longest axis; frontal lobes high, not passing over anterior clypeal margin; with head in full-face, antennal scapes almost reaching posterior margin of head; in profile, anteroventral corner of head with bluntly angled process; subrectangular, slightly shorter than high; subpetiolar process well developed, subrectangular. Dorsom of head with fine dense punctures; dorsa of mesosoma and petiole with dense macropunctues; mesopleuron and lateral surface of propodeum sculptured (irregularly longitudinally striate); declivity of propodeum recticulate with smooth and shiny interspaces; third and fourth metasomal tergites with dense foveae. Body entirely reddish brown to dark brown.

Worker description

Measurements. Holotype: TL 6.94, HL 1.31, HW 1.31, ED 0.19, SL 0.98, ML 1.13, PW 0.92, MSL 1.93, PL 0.62, PH 0.91, DPW 0.72, CI 100, SI 75, OI 15, MI 86, LPI 147, DPI 115.

Paratype workers (n = 3): TL 6.55–6.65, HL 1.22–1.29, HW 1.19–1.29, SL 0.92–1.01, ED 0.17–0.20, ML 0.92–0.99, PW 0.83–0.92, MSL 1.72–1.78, PL 0.59–0.63, PH 0.79–0.83, DPW 0.66–0.69, CI 95–97, SI 78–82, OI 14–16, MI 74–78, LPI 132–139, DPI 105–117.

Head: In full-face view head rectangular, almost as long as broad, with sides convex and posterior margin feebly concave; posterolateral corners of head roundly convex. Mandibles long and slender, inner margin of mandible with 5 teeth (fig. 7). Median clypeal lobe trapezoidal, shorter than broad; broadest anteriorly, with lateral margins clearly diverging from one another in particular on their anterior half; anterior margin of clypeal lobe weakly concave; lateral margin and anterior margin meet so as to form sharp angle. Eyes relatively large, composed of ca. 15 ommatidia along longest axis, located close to the base of mandibles; distance between mandibular base to anterior margin of eye shorter than half length of eyes. Antennal scapes relatively long, clavate, reaching posterior margin of head; flagella incrassate towards apex, apical segment as long as segments IX, X and XI combined. Frontal lobes low, passing over anterior clypeal margin. Median longitudinal frontal sulcus deep, slightly extending beyond level of posterior margin of eyes. Ventral face of head with bluntly angled process in the middle and close to the anterior margin.

Mesosoma: Stout, in profile view pronotum weakly convex dorsal outline; promesonotal suture and metanotal groove distinct, narrow; upper portion of metapleura shallowly impressed; in dorsal view pronotum clearly broader than mesonotum and propodeum; mesonotum short, rectangular, about 1/3 length of pronotum in dorsal view.

Metasoma: Dorsum of propodeum weakly convex, rounded into declivity of propodeum; the latter shallowly concave. Petiole in profile subrectangular, distinctly shorter than high, its anterior face vertical with weakly convex, dorsal outline convex, posterior face flat vertical; in dorsal view, petiolar node trapezoidal and slightly shorter than broad (DPI 105–117), anterior margin convex, but posterior margin flat; subpetiolar process well developed, subrectangular. Metasoma segments III–IX elongate; in dorsal view, metasoma segment III about halflength of metasoma segment IV. Sting long, sharp and upcurved.

Dorsum of head with dense punctures, with area between punctures smooth and shiny; ventral surface of head smooth and shiny; scape with dense punctures but shiny; mandible largely smooth and shiny with a few small punctures; dorsa of mesosoma and petiole with dense macropunctures, areas between punctures smooth and shiny; lateral surface of propodeum irregularly longitudinally striate; declivity of propodeum reticulate; third and fourth metasomal tergites with dense foveae.

Head and body with dense erect and suberect hairs mixed with dense decumbent pubescence. Antennal scape with sparse suberect hairs and dense decumbent pubescence. Entire body reddish brown or dark brown; hairs and pubescence reddish brown.

Habitat. The type series was collected from a rotten log on the forest floor in a lowland dry evergreen forest. One specimen from Phu Kheao wildlife sanctuary was collected using a pitfall trap in a dry dipterocarp forest.

Distribution. Thailand (Nakhon Ratchasima and Chiyaphum Provinces, fig. 52).

Comparative notes. M. sakaeratensis is most similar to M. conicara Xu, 1998 in general appearance and with low frontal lobes (figs. 36 and 46). This species can be distinguished from M. conicara by the following characteristics: smaller size (TL 6.55–6.94 in M. sakaeratensis ; TL 7.20–8.30 in M. conicara ); head with sparse punctures, partly smooth and shiny (dense punctures all over head in M. conicara , see figs. 36 and 46 for comparison); petiole more rectangular, shorter than high and subpetiolar process well developed (petiole more squared and subpetiolar process low, its ventral outline weakly concave in M. conicara ); in dorsal view petiole slightly shorter than broad (clearly longer than broad in M. conicara ); clypeal lobe not as large as in M. conicara (see fig. 36 and fig. 46 for comparison); antennal scapes reaching posterior margin of head (slightly extending beyond posterior margin of head in M. conicara ). Myopias sakaeratensis is similar to M. crawleyi but can be easily separated from the latter by the following characteristics: frontal lobes low, passing over anterior clypeal margin (high and not passing over anterior clypeal margin in M. crawleyi ); mesopleron and lateral face of propodeum sculptured (smooth and shiny in M. crawleyi ); propodeal declivity reticulate with smooth and shiny interspaces (entirely smooth and shiny in M. crawleyi ); posterior ¾ of subpetiolar process rectangular, its ventral outline weakly convex (posterior ¾ of subpetiolar process triangular, its ventral outline almost straight in M. crawleyi ); slightly larger size (HW 1.19–1.29 mm in M. sakaeratensis ; HW 0.96–0.99 mm in M. crawleyi ).

Figures

FIGURES 34–36. Myopias sakaeratensis sp. nov. (holotype worker, THNHM-I-00291); 34, Body in profile view; 35, body in dorsal view; 36, head in full-face view.