Apechthis cantika Watanabe & Takasuka

Watanabe, Kyohei & Takasuka, Keizo, 2013, Description of Apechthis cantika sp. n. from Sulawesi Is., Indonesia with redescription of the holotype of A. taiwana Uchida (Hymenoptera, Ichneumonidae, Pimplinae), Journal of Hymenoptera Research 31, pp. 105-117 : 106-110

Apechthis cantika Watanabe & Takasuka sp. n. Figs 1-16, 18-22

Diagnosis.

Propodeum largely smooth medially, without median longitudinal carinae (Figs 3, 14); metasomal tergite I with pair of strongly convex keels and strongly angulate in lateral view (Figs 1, 15); all tarsal claws with basal tooth (Figs 10-12); male flagellum with longitudinal ridge on flagellomere VI to basal half of IX (Fig. 6); metasoma entirely yellow (Figs 1, 3).

Description.

Female: body 10.0-12.0 (HT: 12.0) mm long, fore wing 10.0-12.0 (HT: 12.0) mm long. Head polished, punctate, 0.5 times as long as wide in dorsal view; clypeus 0.6 times as long as wide, flat, smooth, finely punctate along apical margin and supraclypeal suture; face 0.7 times as long as wide, finely punctate, medially with weak longitudinal convexity (Fig. 5); frons smooth, weakly concave above antennal sockets; malar space 0.2 times as long as basal width of mandible; basal portion of mandible flat; vertex and gena minutely and finely punctate; OOL/OD 0.7; POL/OD 1.0; antenna with 25-27 (HT: 27) flagellomeres, terminal segment with columnar projections (Figs 7, 8); flagellomere I 1.3 times as long as flagellomere II.

Mesosoma polished, sparsely punctate; pronotum laterally largely smooth; mesoscutum finely, densely punctate; anterior half of mesopleuron strongly convex; upper end of epicnemial carina reaching lower apex of pronotum (Fig. 9); episternal scrobe large; lower division of metapleuron largely smooth excluding along pleural carina; propodeum smooth medially, sparsely punctate laterally, with pleural carina and posterior part of lateral longitudinal carina (Figs 3, 14, 15); lateromedian longitudinal carina present only as basal tubercle (Figs 3, 14); other carinae absent.

Legs: claws of all legs with basal tooth (Figs 10-12); hind femur 3.5 times as long as deep.

Wings: fore wing with vein Cu-a distad to vein Rs+M by 0.4-0.5 (HT: 0.5) times length of vein Cu-a, with rectangular areolet receiving vein 2m-cu near apical 1/3 (Fig. 13); hind wing with distal abscissa of vein Cu1 much closer to vein 1A than to vein M, basal abscissa of vein Cu1 0.5 times length of vein cu-a; 9 (left) or 11 (right) distal hamuli.

Metasoma polished, punctate; tergite I 1.1-1.2 (HT: 1.1) times as long as maximum width, smooth, with pair of strong median convexities (Figs 1, 3, 14, 15), con vexity nearly angulate in lateral view (Figs 1, 15); tergite II 0.8 times as long as maximum width, anterior 1/5, gastrocoeli and posterior margin smooth (Figs 3, 14); tergites III to VII punctate excluding posterior margin; lower valve of ovipositor with 13 teeth (Fig. 16); ovipositor sheath 0.8 times as long as hind tibia.

Colour (Figs 1-4). Body yellow, except for: apex of mandible, dorsal surfaces of scape and pedicel, flagellomere I and II, small median spot on mesoscutum, pair of small spots on posterior margin of propodeum, apices of claws (including teeth) of legs, base of hind femur, wing veins including stigma, ovipositor, ovipositor sheath excluding apex black; posterior part of vertex, scuto-scutellar groove, apex of hind tibia, hind tarsus excluding base of first segment blackish-brown; above antennal socket on frons, ocellar area, three longitudinal stripes on mesoscutum (these stripes sometimes darkened), small areas near epicnemial carina, epistomal scrobe, subalar prominence brown; wings yellowish-hyaline.

Male: similar to female, except following characters: body 8.0-9.0 mm long, fore wing 8.0-8.5 mm long; clypeus 0.5-0.6 times as long as wide; face slightly wider, 0.7-0.8 times as long as wide; OOL/OD 1.0; POL/OD 0.7; flagellum with longitudinal ridge on flagellomere VI to basal half of IX (Fig. 6); tergite I 1.2-1.3 times as long as maximum width; tergite II 1.0 times as long as maximum width; and 8 (left) or 9 (right) distal hamuli.

Male terminalia: subgenital plate elongate, with acute apex, apico-lateral area without setae (Fig. 18); paramere with membranous inner surface, apex covered with dense setae and ventral margin with very dense, long setae near apex (Figs 19-21); apical margin of paramere sharp, apex not projecting beyond apex of aedeagus (Figs 19, 20); aedeagus weakly widened apically, with basal apodeme slightly shorter than penis valve (Fig. 22).

Colourationsimilar to female but brown areas somewhat darker.

Type series.

Holotype: Female, Mt. Lompobatang, Gunung, South Sulawesi Prov., INDONESIA, 1977m alt., 14. xii– 21. i.2011, Keizo Takasuka leg. (Malaise trap, 5°23'26.74"S, 119°56'1.14"E) (LIPI). Paratypes: 1 female and 2 males, same data as holotype (1 male in LIPI; 1 female and 1 male in EUM).

Distribution.

Indonesia (Sulawesi).

Etymology.

The specific name is derived from the Indonesian word “cantik”, meaning “beautiful”.

Remarks.

This species can easily be distinguished from most other Apechthis species by its yellow body without dark areas on the metasomal tergites (Figs 1-4), and from all yellow Neotropical species by the keel on the first metasomal tergite being strongly angulate in lateral view (Figs 1, 15 arrow) (weaker or not angulate in the Neotropical species). Although this species morphologically much resembles Apechthis taiwana , it can be distinguished by the upper end of the epicnemial carina reaching the lower apex of the pronotum (Fig. 9) (in taiwana it extends dorsally, reaching the middle of the pronotum: Fig. 17), smoother metasomal tergites I and II (Figs 3, 14) (taiwana relatively densely punctate: Fig. 24), and the entirely yellow metasoma (Figs 1, 3) (taiwana with conspicuous black or brown areas: Figs 23, 24). This species is also the southernmost representative of Apechthis in the Oriental region.

Although the columnar projections on the terminal antennal segment of females (Figs 7, 8) was pointed out as a synapomorphy in Pimplini ( Gauld et al. 2002), relating to host-searching behaviour ( Broad and Quicke 2000), it is also shared with the male of Apechthis cantika sp. n. and thus this structure may serve other functions.

Asymmetric numbers of hamuli in “left” and “right” wings were observed in two Oriental species, Apechthis cantika sp. n. (L<R: 2 females and 2 males, asymmetry at a rate of 100%) with stable numbers of hamuli and Apechthis taiwana (L>R: 1 female, holotype, asymmetry at a rate of 100%, see following description). But in two Palaearctic species collected from Japan, Apechthis capulifera (Kriechbaumer, 1887) (19 females and 9 males deposited in KPMNH, asymmetry at a rate of ca. 47%) and Apechthis rufata (Gmelin, 1790) (18 females and 12 males deposited in KPMNH, asymmetry at a rate of ca. 47%), although asymmetric hamuli numbers are also found in approximately half of specimens, both the side of asymmetry and numbers of hamuli are unstable, not supporting the apparently stable asymmetry trend observed in the Oriental species, but based on small numbers of specimens.