Metapone titan, Taylor, Robert W. & Alpert, Gary D., 2016

Taylor, Robert W. & Alpert, Gary D., 2016, The myrmicine ant genus Metapone Forel (Hymenoptera: Formicidae): a global taxonomic review with descriptions of twelve new species, Zootaxa 4105 (6), pp. 501-545 : 525

Key to the Micronesian, Melanesian and Pacific species of Metapone

1. Subpetiolar extension a narrow, hook-like process, its base occupying less-than one-quarter of the subpetiolar edge in lateral view............................................................................................... 2

Subpetiolar extension an expansive triangular or rounded/subrectangular process, its base occupying at least half the subpetiolar edge in lateral view................................................................................. 3

2(1) The largest known Metapone species (gyne HW 2.3–2.5 mm, TL ca. 14–16 mm). Clypeal rostrum relatively very large and broad, projecting ca 0.68x its apical width beyond the lateral sections of the clypeus in frontal view ( Papua New Guinea: New Ireland, gyne only, Figs 111–115 )............................................................... M. titan sp.n.

Smaller species (known HW 1.28mm, TL ca 7.5 mm). Clypeal rostrum smaller, projecting ca 0.44x its apical width beyond the lateral sections of the clypeus in frontal view. (mainland Papua New Guinea, worker only, Figs 101–105 ).. M. philwardi sp.n.

3(1) Clypeus apically rostrate, with a strong proboscis-like median extension projecting well beyond its lateral sections........ 4

Clypeus projecting but barely rostrate, median apical section only slightly advanced beyond lateral sections, anterior border with an apical median, tab-like projection, a little narrower than the body of the sclerite, to which it is stepped on either side...................................................................................................... 6

4(3) Smaller species (HW 0.87mm). ( Solomon Islands: San Cristobal, gyne only, Figs 106–110 )............. M. salomonis sp.n

. Generally larger species HW 0.85–1.22mm ( Micronesia, New Guinea, New Britain)................................ 5

5(4) (In gynes & workers) Frons, cheeks, clypeus, promesonotal dorsum and sides of pronotum and petiole distinctly and regularly longitudinally or diagonally finely striate ( Figs 71 –80). Clypeal projection relatively a little shorter and narrower than in the alternative ( Figs 71, 73 , 76, 78). Petiolar node relatively short and narrow ( Figs 72, 74, 75 , 77, 79, 80). Apex of subpetiolar extension inclined posteriorly, broadly rounded ( Figs 72, 75 , 77, 80) ( Micronesia, mainland New Guinea, New Britain, gyne and worker)...................................................................... M. krombeini M.R. Smith

(In gynes & workers) Striae in relevant areas less-strongly developed and less-regular; partly effaced, especially on frons and cheeks ( Figs 81 –90). Clypeal proboscis relatively short and broad ( Figs 81, 83 , 86, 88). Petiole relatively short in lateral and dorsal view ( Figs 82, 84, 85 , 87,89). Subpetiolar extension similar to alternative, but with its apex acutely pointed ( Figs 82, 85 , 87, 90) (mainland New Guinea, gyne and worker)............................................ M. truki M.R. Smith

6(3) Larger species (HW 1.48 mm, TL ca 8.8mm (N=1). Subpetiolar extension subrectangular, ca twice as long as deep, the outer corners minutely rounded (New Guinea, Gyne only, Figs 91–95 )................................. M. enigmatical sp.n.

Smaller species (HW 1.02–1.09mm, TL ca 7.1–7.4mm). Subpetiolar extension an approximately equilateral triangle, inclined posteriorly ( Fiji: Viti Levu, gyne only, Figs 96–100 ).............................................. M. manni sp.n.

Figures

FIGURES 111 – 115. Metapone titan. holotype gyne, see text for dimensions.

FIGURES 101 – 105. Metapone philwardi, holotype worker, see text for dimensions.

FIGURES 106 – 110. Metapone salomonis. holotype gyne, see text for dimensions.

FIGURES 71 – 75. Metapone krombeini, holotype gyne; FIGURES 76 – 80. Worker, see text for dimensions.

FIGURES 81 – 85. Metapone truki, holotype gyne; FIGURES 86 – 90, worker, see text for dimensions.

FIGURES 91 – 95. Metapone enigmatica, holotype gyne, see text for dimensions.

FIGURES 96 – 100. Metapone manni. holotype gyne, see text for dimensions.