Myrmicaria chapmani, Zettel & Laciny & Balàka & General, 2018

Zettel, Herbert, Laciny, Alice, Balàka, Pia & General, David Emmanuel M., 2018, On the taxonomy of Myrmicaria Saunders, 1842 (Hymenoptera: Formicidae) in the Philippines, Raffles Bulletin of Zoology 66, pp. 610-623 : 616-618

Myrmicaria chapmani new species

( Figs. 9–12 , 19 )

Etymology. Named after James Wittenmyer Chapman (1880–1964), myrmecologist at Silliman University, Dumaguete, Negros Oriental, and at Harvard University, to honour his passionate dedication to science and his sense of social responsibility.

Material examined. Holotype (worker) ( NMNH) from Negros Island, Negros Oriental Province, Sibulan, Lake Balinsasayao – Lake Danao area, 28–30 October.

Paratypes: 19 workers ( NHMW, CZW) from the same sample ; 1 worker ( MCZ), Negros Island, Negros Oriental Province, Dumaguete , “Lake Bell’s cabin”, coll. J.W. Chapman, 22 May 1940 ; 6 workers ( MCZ), Dumaguete , coll. J.W. Chapman, 29 March 1924 ; 5 workers ( MCZ), same locality and collector ; 9 workers ( MCZ), same locality and collector, except 1,000 –1,500 ft. a.s.l. ; 5 workers ( MCZ), same locality and collector, except 1,500 ft. a.s.l. ; 3 workers ( MCZ) same locality and collector, except 2,000 ft.

Diagnosis (worker). In exact full-face view, eyes not touching outline of head. Scape relatively short, SI = 92–100. Sides of mesonotum weakly bulging; posterior surface with longitudinal rugae. Medial carina of mesonotum extended onto base of propodeum. Propodeal spines moderately long, slightly directed dorsocaudally, not continuing dorsal outline of propodeum. Peduncle of petiole moderately long. Base of gaster tergite 1 without striation. Gaster usually infuscated except anterior part of tergite 1.

Description (worker). Measurements of holotype: HW 1.40; HL 1.36; SL 1.35; SW 0.14; TL 6.20; Pmin 0.16; PW 0.40; PPW 0.41; SpD 0.42; PrL 0.87; FeL 1.92; ML 1.79; PnW 1.01; CI 103; SI 96; FeI 137.

Measurements of paratypes: min-max (n = 31): HW 1.25–1.51; HL 1.22–1.49; SL 1.24–1.43; SW 0.12–0.16; TL 5.35–6.85; Pmin 0.13–0.21; PW 0.35–0.42; PPW 0.36–0.45; SpD 0.36–0.46; PrL 0.77–1.01; FeL 1.73–2.09; ML 1.57– 1.99; PnW 0.85–1.14; CI 99–110; SI 92–100; FeI 125–143.

Structures: Head ( Fig. 11 ) roundish to slightly transverse; posteriorly with strong piliferous punctures; most areas dorsally and laterally with relatively strong longitudinal rugae. Temples slightly swollen; eyes not touching outline of head in exact full-face view. Clypeus with distinct, complete median carina and few longitudinal rugae. Mandible with sharp longitudinal rugae; apical margin with four teeth. Entire mesosoma, dorsally and laterally, with predominantly longitudinal rugae, with very few transverse elements, except for the strong transverse ridge at midline of mesonotum and a second (often complete) ridge near its anterior margin. A strong median carina from anterior margin of pronotum onto base of propodeum. Pronotum with relatively short, rather ventrally directed teeth that are weakly protruding laterally. Sides of mesonotum slightly bulging. Metanotal groove narrow and deep, in dorsolateral view lateral margin forming a very obtuse angle. On propodeum, the area between bases of spines moderately concave. Propodeal spines moderately long, directed strongly upwards, slightly diverging. Nodes of petiole and postpetiole rounded; peduncle of petiole comparatively short. Gaster with piliferous punctures; base of gaster tergite 1 without striation.

Setae abundant on trunk and appendages. Dorsal setiferation composed of two types of setae; short setae about half as long as long ones (but somewhat longer on gaster). On head dorsum, petiole and postpetiole all setae suberect. Short setae abundant on mesosoma sides, but scarce on its dorsum. On gaster, long setae suberect, short setae subdecumbent anteriorly, suberect posteriorly.

Colour of trunk yellowish brown, except gaster more strongly infuscated. In many paratypes, trunk yellow, obviously faded from previous storage in ethanol. All appendages yellow. All setae pale yellow.

Comparative notes. Myrmicaria chapmani new species is so far the only species known from Negros. The combination of a long median carina on the mesosoma that reaches the base of propodeum ( Fig. 19 ) and the non-striate base of gaster ( Fig. 12 ) distinguishes it clearly from Philippine congeners. Due to slightly swollen temples, the eyes are not touching the outline of the head in full-face view ( Fig. 11 ). This character is almost unique among Philippine Myrmicaria species (seen also in two aberrant specimens of an undescribed species from Luzon).

Distribution. Myrmicaria chapmani new species is known from a few localities in the south-eastern part of Negros Island. No other Myrmicaria species are known from Negros.

Figures

Figs. 9–10. Holotype worker of Myrmicaria chapmani new species in lateral (9) and dorsal (10) view.

Figs. 11–12. Holotype worker of Myrmicaria chapmani new species: (11) head in full-face view; (12) postpetiole and base of gaster tergite 1 in dorsal view.

Figs. 17–20. Mesosoma in dorsal view: (17) Myrmicaria aphidicola from Bukidnon; (18) M. buenaventei new species (holotype); (19) M. chapmani new species (holotype); (20) M. transversa new species (holotype).