Tanyxiphium Huber

Huber, John T., 2015, World reclassification of the Gonatocerus group of genera (Hymenoptera: Mymaridae), Zootaxa 3967 (1), pp. 1-184 : 57-58

Tanyxiphium Huber , gen. n.

( Figs 248–288)

Type species. Tanyxiphium seychellense Huber , by present designation.

Diagnosis. Within Gonatocerini, the species of Tanyxiphium are distinguished by the following combination of features: female mandible small, shorter than maxilla, with 3 minute teeth ( Figs 258, 264, 273, 276, 281); pronotum entire ( Figs 262, 269, 271, 285); dorsellum rhomboidal ( Figs 252, 262, 269); ovipositor sheaths in Old World species enormously long ( Fig. 248) but in New World species ovipositor sheaths usually much shorter ( Figs 253, 254), slightly to moderately extending beyond apex of gaster. Males have a distinct ‘neck’, pronotum entire but with seeminngly widely separated lateral lobes (due to different colour of median area) ( Figs 272, 275, 284), a wide head, and mandibles of nomal size (crossing each other when closed), with 3 normal teeth ( Figs 255, 280, 282).

Description (based mainly on Old World species). FEMALE. Medium to large, slender specimens, 770– 1230 Μm in length. Colour. Almost entirely dark yellow (except brown flagellum) to almost entirely brown. Fore wings fairly hyaline, often with a faint brown suffusion especially behind and well beyond venation. Head. Head ( Figs 249, 258, 264, 265, 271, 273) about 2.08–2.55 × as wide as long and 1.17–1.28 × as wide as high; in lateral view with anterior surface distinctly angular, above torulus almost flat and vertical and below torulus almost flat and strongly receding to mouth. Face ( Fig. 263) about 0.8–0.9 × as wide as high, widest at level of antennifer, slightly converging above and below; subantennal sulci present and converging ventrally, the distance between them at mouth margin less than half their distance to preorbital sulci; preorbital sulcus fine, appressed against eye at level of torulus, then apparently curving medially around ventral margin of torulus and meeting dorsal apex of subantennal sulcus. Toruli at least half their length from transverse trabecula. Eye in lateral view higher (about 1.2– 1.4 ×) than long, much of its posterior margin extending to back of head or almost so, then at about one third eye height diverging slightly away from back of head. Malar space 0.4–0.6 × eye height; malar sulcus very fine, slightly curved, extending from anteroventral margin of eye to posterolateral angle of mouth. Gena in lateral view narrow or absent behind dorsal two-thirds of eye, narrow ventrally, merging into occiput by rounded angle. Vertex in lateral view strongly oblique and forming a very obtuse angle with face ( Fig. 275) but sometimes almost in same plane as face, posteriorly separated from occiput by fairly sharp angle and a transverse sulcus behind and between ocelli ( Fig. 271). Ocelli with LOL about 0.35–0.45 × POL and OOL about 0.3–0.4 × POL, the lateral ocelli oblique, facing posteriorly and on line with occipital junction, with 4 setae between them. Occiput entire. Mouth opening small, its width about equal to malar space. Labrum with 2 or 3 setae medially and 1 laterally. Mandibles small, at most as long as maxillae barely meeting medially when closed, with 2 or 3 minute teeth ( Figs 249, 258, 264, 276). Antenna. Scape about 5.7 –6.0× as long as wide, with radicle distinct, narrow, about 0.28 × scape length; pedicel about 0.29 × scape length, distinctly longer than fl 1; funicle 8 -segmented, the segments all longer than wide; clava ( Figs 248, 249, 260, 266), at most about 0.45 × funicle length, with 8 mps. Mesosoma. About 1.3–1.5 × as long as wide, 1.6–1.7 × as long as high, and 1.0– 1.2 × wide as high. Pronotum in dorsal view very short, usually just visible medially ( Figs 252, 262, 269), occasionally a little longer and easily visible, apparently entire but with a median area bordered laterally by a paler area so lateral lobes apparently widely separated (somewhat resembling Lymaenon ); in lateral view with median surface separated from vertical lateral surface by sharply rounded angle. Pronotal spiracle in wide shallow depression (somewhat resembling Lymaenon ), slightly larger than propodeal spiracle ( Fig. 269). Propleura normal. Prosternum triangular, divided posteriorly by longitudinal sulcus extending for various lengths. Mesoscutum in dorsal view with fairly wide but shallow (not or barely visible in micrographs), almost straight, slightly diverging notauli. Transscutal articulation almost straight. Scutellum slightly longer than wide. Axilla normal. Prepectus narrowly triangular, widest near dorsal apex. Mesopleuron spindle shaped and truncate at both ends, with very shallow femoral depression and with fine, barely visible line separating narrower mesepimeron from wider mesepisternum. Metanotum with triangular dorsellum, its posterior margin distinctly convex ( Figs 252, 262, 269). Metapleuron triangular, separated from propodeum by thin, slightly curved line.

Propodeum in lateral view sloping slightly, in almost same plane as dorsellum or at an obtuse angle, in dorsal view smooth, without carinae and anteriorly abutting metanotum. Propodeal spiracle small, separated by at most its own diameter from metanotum. Wings. Fore wing 3.0– 4.2 × as long as wide, without microtrichia to distinctly beyond apex of venation except for cubital line of microtrichia extending to almost to base of parastigma and up to 3 scattered microtrichia between it and apex of venation ( Figs 251, 261, 268). Venation almost 0.4 × wing length. Submarginal vein with the usual basal setae (1 macrochaeta and 1 hypochaeta) and a hypochaeta near base of parastigma. Remaining venation (parastigma + stigmal vein) about 0.5 × length of submarginal vein, with hypochaeta closer to distal than to proximal macrochaeta, and 1 or 2 shorter setae between the macrochaetae. Stigmal vein with apex slightly oblique (somewhat truncate). Hind wing normal. Venation about 0.4 × wing length. Metasoma. Petiole short, wider than long ( Figs 262, 269, 270). Gaster about 2.1–3.5 × as long as high. Terga without or scarcely with membrane visible between them ( Figs 248, 253, 254, 263, 270). Ovipositor sheaths short and exserted only slightly beyond gaster apex to more than 2.0× gaster length and usually well over entire body length, with its exserted portion often curved dorsally and with 1 subapical seta ( Figs 248, 253, 254).

MALE. Body length 790–1100. Colour. In yellow species where male can be correctly associated with conspecific female, colour more uniform than in female, except pronotum either with narrow longitudinal white submedian bands separated by brown median area or entire median area white. Antenna. Flagellomeres about 2.5– 3.2 × as long as wide, at most with 5 mps, the basal segments each with fewer mps ( Fig. 256); scape about 5.3–5.8 × as long as wide, with radicle about 0.3–0.4 × scape length and not very clearly separated; pedicel about 0.4 × scape length and shorter than fl 1. Head. Head about 3.3 × as wide as long. Mandibles normal, overlapping when closed, with 3 normal teeth ( Figs 255, 280, 282). Mesosoma. Pronotum long and more gradually tapering anteriorly than in female, the head appearing well separated from mesosoma ( Fig. 272) and the propleura appearing widely separated anteriorly. Metasoma. Genitalia with aedeagal apodemes fused at junction with base of aedeagus and not extending anteriorly past apex of apodeme of genital sternum ( Fig. 257).

Discussion. Tanyxiphium is most similar to Gonatocerus but differs as follows: head (especially mandibles) sexually dimorphic, ocellar triange with 4 setae between the lateral ocelli ( Fig. 272), and pronotum entire. Females of the various species are distinguished from one another mainly on different ovipositor sheath lengths. Features to associate males correctly with the corresponding females and to identify the males to species are not clear, though body colour may be useful. Males can be associated by collecting them repeatedly in the same collecting events as the corresponding females. The males of only two of the five species are known and correctly associated with the corresponding females.

Etymology. From Greek “tany-” meaning long, and “xiphos” (diminutive “xiphion”) meaning sword, referring to the long, greatly exserted ovipositor and sheaths in most species. The gender is neuter.

Distribution. Tanyxiphium species occur in the Oriental, Afrotropical, and Neotropical regions. Numerous specimens representing several species were seen, representing both Old World and Neotropical species. Only three are described here. Three specimens collected at 2070 m in Nepal were seen; this is the highest elevation recorded for specimens of the genus. In the Old World the eastern-most specimens came from Malaysia (Sabah) and the western-most from Ivory Coast. In the New World the genus occurs from Costa Rica south to Argentina.

Hosts and habitat. Hosts are unknown. Specimens have been collected in forests; one species on a small island may be in a dry, more open habitat.

Included species:

Tanyxiphium breviovipositor Huber ; holotype ♀ in IAVH. TL: Colombia, Vichada, Parque Nacional Natural

Tuparro.

Tanyxiphium harriet (Zeya) , comb. n. from Gonatocerus . Gonatocerus harriet Zeya, 2015: 87 ; holotype ♀ in

NBAII. TL: India, Kerala, South Andaman, Mt. Harriet .

Tanyxiphium longissimum Huber ; holotype ♀ in QSBG. TL: Thailand: Petchabun Khao Kho National Park. Tanyxiphium perforator (Ogloblin) ; comb. n. from Gonatocerus . Lymaenon perforator Ogloblin 1953: 4 ; holotype

♀ in MLPA (examined). De Santis, 1967: 10, 105 (transferred to Gonatocerus ); Triapitsyn et al., 2010: 34

[questionable placement in Gonatocerus ( Gonatocerus )]. TL: Argentina, Misiones, San Ignacio district, Rio

Yabebirí.

Tanyxiphium seychellense Huber ; holotype ♀ in BMNH. TL: Seychelles, Cousin Island.