Metapone

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 : 512

Key to the Asian species of Metapone

This key is of necessity based largely on the characters of gynes. It emphasizes features which we believe will also enable identification of worker specimens. The male-based M. hewitti is not included.

1. All body surfaces smooth, shining, very highly reflective, with at most a few extremely obscure, minute, generally ripple-like apparent vestiges of longitudinal striation ( Figs 34–38 ). Head relatively broad (CI of only known specimen 91); clypeal outline in frontal view broadly semicircular. ( Philippines: Luzon, gyne).................................. M. bakeri Wheeler Dorsal and lateral surfaces of head and mesosoma densely, finely, longitudinally striate. Known CI values less than 76. Clypeus differently structured........................................................................... 2

2(1) Median section of clypeus extended forwards beyond the lateral sections to form a more-or-less proboscis-like structure which lacks median denticles (well-separated denticles at either end of the anterior border may be present)................... 3 Median section of clypeus not protruding forward beyond its lateral sections, the anterior border with a pair of small approximate median denticles.................................................................................. 8

3(2) Head relatively narrow (HW 1.54, CI 68). Petiolar node in dorsal view more than twice as long as wide, with strong posterolateral tooth-like projections. Subpetiolar extension a long, low subrectangular, translucent lamina extending back almost to the subpetiolar angle; the latter acutely spine-like in lateral view. ( Taiwan, gyne only, Figs 28–33 )........... M. sauteri Forel. Species from distant other areas ( Sri Lanka, Philippines, Indonesia). HW usually well less than in the alternative prescription and/or CI with a higher value. Petiolar proportions and subpetiolar configuration clearly dissimilar.................... 4

4(3) Subpetiolar process unusually configured. In lateral view the much-reduced longitudinal, acutely triangular posterior face (which lacks a framing lamella) so strongly inclined forwards that its profile almost aligns with the adjacent subpetiolar edge. The subpetiolar angle extended ventrally as a relatively large, acutely erect spine-like process, well separated from the more anterior, small, vertically tabulate, translucent subpetiolar extension, the posterior apex of which is hook-like, inclined posteriorly ( Indonesia: Java, worker only, Figs 62–65 ).................................................. M. javana sp.n. Petiolar sternite differently constructed: subpetiolar angle usually (not always) distinct, not spinosly extended; subpetiolar extension usually differently constructed: relatively large, or small and triangular................................... 5

5(4) Posterior face of subpetiolar process relatively large, with a translucent framing lamella clearly evident in profile view. Subpetiolar angle distinct, in lateral view slightly extended as a pointed process, partly including the framing lamella. Petiolar node in dorsal view approximately subquadrate..................................................................... 6 Posterior face of subpetiolar process reduced; subpetiolar angle either rounded in lateral view, with the reduced profile of the posterior face grading smoothly into the profile of the subpetiolar edge; or without clear presence of a subpetiolar angle, so that the subpetiolar edge in effect continues directly to the posterior base of the sternite................................. 7

6(5) Subpetiolar extension relatively large, longitudinally subrectangular with minutely rounded corners; its base almost as long as the ventral subpetiolar edge. ( Sri Lanka, gyne & worker—Figs 16–27)............................... M. greeni Forel Subpetiolar extension a small, sub-rectangular, barely translucent plate with its posterolateral corner extended to form a more- or less hook-like structure; its base about half as long as the ventral subpetiolar edge ( Malaysia: Sabah, gyne & worker, Figs 52–55 )........................................................................... M. quadridentata Eguchi

7(5) Anterior border of median clypeal projection subtended by a minute parallel groove bearing a rank of about 6 stout, forwardlydirected pale bristle-like hairs. Outline of anterior clypeal border above the groove shallowly rounded/convex in frontal view, the edge below the groove with a small tooth-like terminal angle on each side. Subpetiolar extension a dependant subrectangular, posteriorly inclined, relatively large tab, more-or-less transversely rectangular in shape. ( Indonesia: Bali, gyne only, Figs 56–61 )................................................................................ M. balinensis sp.n. Anterior border of anteromedian clypeal process a single shallowly concave edge without an accompanying groove or hairline; anterolateral corners subdentate. Subpetiolar extension a small approximately right-angled triangle. ( Indonesia: Lombok, gyne only, Figs 66–70 ).................................................................. M. wallaceana sp.n.

8(2) Larger species, HW of 2 known gynes 1.00– 1.04mm. ( Indonesia: Sumatra, gyne only, Figs 42–46 ).... M. jacobsoni Crawley Smaller species, HW of 2 known gynes 0.95, 0.98mm. ( Philippines: Luzon, Negros, gyne only, Figs 47–51 )................................................................................................... M. gracilis Wheeler

Figures

FIGURES 34 – 38. Metapone bakeri, holotype gyne, see text for dimensions.

FIGURES 28 – 33. Metapone sauteri, holotype gyne, see text for dimensions.

FIGURES 62 – 65. Metapone javana. holotype worker, see text for dimensions.

FIGURES 52 – 55. Metapone quadridentata, paratype worker, HW 1.21, PNW 0.57, MSL 1.42.

FIGURES 56 – 61. Metapone balinensis, holotype gyne, see text for dimensions.

FIGURES 66 – 70. Metapone wallaceana, holotype gyne, see text for dimensions.

FIGURES 42 – 46. Metapone jacobsoni, holotype gyne, see text for dimensions.

FIGURES 47 – 51. Metapone gracilis, holotype gyne, HW 0.95, PNW 0.71, MSL 2.07.