Platyscelio

PlatyscelioKieffer 1905 :11 Original description. Type: Platyscelio pulchricornis Kieffer, by monotypy. Brues 1908 : 27, 40 (diagnosis, list of species, keyed); Kieffer 1908 : 113 (keyed); Kieffer 1910 : 62, 66 (description, list of species, keyed); Dodd 1913 : 130 (keyed); Kieffer 1913 : 222 (description); Brues 1922 : 21 (diagnosis, figure); Kieffer 1926 : 265, 553 (description, keyed, key to species); Mani 1941 : 29 (catalog of species of India); Muesebeck and Walkley 1956 : 386 (citation of type species); Baltazar 1966 : 186 (catalog of species of the Philippines); Masner 1976 : 10, 55 (description, keyed); Mani and Sharma 1982 : 190 (description); Galloway and Austin 1984 : 9, 75 (diagnosis, keyed); Johnson 1992 : 461 (catalog of world species); Austin and Field 1997 : 34, 68 (structure of ovipositor system, discussion of phylogenetic relationships); Lê 2000 : 31 (keyed); Rajmohana K. 2006 : 117, 128 (description, keyed); Kononova and Kozlov 2008 : 25, 319 (description, keyed).

Diagnosis.

Platyscelio is distinguished from most other genera of Scelioninae sensu Masner (1976) by the strongly dorsoventrally depressed, flat, and foliaceous body. A small number of other groups, such as Aradophagus Ashmead and Synoditella Muesebeck, are also more or less strongly depressed. Platyscelio may be distinguished from them by the absence of a netrion; the mandibles are tridentate, with the middle tooth small; the postmarginal vein is very short or absent, clearly shorter than the stigmal vein; and vein R in the hind wing is complete, extending to the hamuli on the costal margin of the wing.

Description.

Moderate-sized, length 3.0-5.6 mm; head prognathous, flattened anteroposteriorly, mesosoma and metasoma strongly dorsoventrally depressed; body black; macropterous.

Head:

Head in dorsal view strongly transverse; vertex laterad of posterior ocellus smooth or with few faint striae, between posterior ocelli finely longitudinally striate; hyperoccipital carina present as fine ridge on vertex between compound eyes; occipital carina absent; posterior ocellus distinctly separated from inner orbit of compound eyes, OOL> diameter of ocellus; compound eye large, appearing glabrous; frons without depression, shallowly convex, with median longitudinal sulcus bifurcating dorsally near median ocellus and ventrally near toruli; interantennal process well-developed, narrow; torular triangle present; submedian carina sometimes present; orbital carina sometimes present; lower frons, including cheek, with weak fanlike striae arising from mandibular condyle; shortest distance on frons between eyes less than eye height; inner orbits weakly diverging ventrally; postclypeus strongly projecting above anteclypeus, subtriangular, anteclypeus short, longest medially, lateral corners not produced; malar sulcus present; gena variably expanded, smooth to longitudinally striate or with few faint striae; labrum hidden by clypeus; mandible short, apex tridentate, middle tooth distinctly shortest, teeth arranged transversely; maxillary palpus 2-segmented, all segments cylindrical; labial palpus 1-segmented, very short; antenna 12-merous in both sexes; radicle very broad, inserted into ventral apex of A1, nearly parallel to longitudinal axis of A1, with small lateral spine; A1 almost triangular and expanded outwardly into spine, particularly in female; A2 distinctly shorter than A3; gustatory sensilla on female antenna arranged in longitudinal pairs on apical antennomeres; clava laterally compressed, claval formula A12-A8: 1-2-2-2-1; male antenna with tyloid on A5.

Mesosoma :

Mesosoma in dorsal view longer than wide, in lateral view much longer than high; pronotum in dorsal view strongly narrowed laterally, anterolateral corner weakly angulate; transverse pronotal carina absent; vertical epomial carina absent; dorsal epomial carina absent; lateral face of pronotum concave; netrion absent; anterior margin of mesoscutum strongly flexed ventrally to meet pronotum; mesoscutum semicircular in outline, posterolateral corner rounded; parapsidal line variably developed; notaulus variably developed: absent, nearly percurrent or percurrent, mesoscutum sometimes with strong sublateral carina paralleling notaulus; skaphion absent; prespecular sulcus and posterior mesepimeral sulcus present; speculum smooth, rarely longitudinally striate ( Platyscelio arcuatus ) transscutal articulation well developed; mesoscutellum rectangular in outline, truncate posteriorly, sculpture smooth to longitudinally striate; axilla small; posterior scutellar sulcus interrupted medially or complete; metanotum narrow, metascutellum clearly differentiated, size of metascutellum variable; dorsal surface of propodeum variable, weakly setose posteriorly; median propodeal sulcus present; plicae well developed; propodeal projections reduced; sternaulus absent; metapleural pit reduced; metapleural sulcus present dividing metapleuron into dorsal and ventral areas; setation of posterior half of ventral metapleural area variable; legs elongate; posterior surface of hind coxa smooth, glabrous to densely setose; trochantellus present; tibial spur formula 1-1-1; tarsal formula 5-5-5; tarsomeres cylindrical, broadening apically; pretarsal claw simple; apex of fore wing extending to or slightly beyond apex of S5 in female and S6 in male, hyaline or infuscate; R straight, extending slightly beyond basal half of length of wing, without strong, elongate bristles, gradually approaching costal margin apically, contiguous with costal margin for distance clearly exceeding length of r-rs (i.e., marginal vein elongate); r-rs straight; R1 usually absent, reduced, stumplike in some species ( Platyscelio arcuatus and Platyscelio mzantsi ) (i.e., postmarginal vein absent); bulla absent; Rs+M (basal vein) weakly to clearly indicated, nebulous; hind wing with R extending from base of wing to hamuli; three hamuli present.

Metasoma:

Metasoma elongate, parallel-sided, strongly flattened dorsoventrally; female with six visible terga and sterna, male with seven visible terga and sterna; second to fifth segments equal in length, third and fourth widest, subequal to each other in size; submarginal ridge developed, defined by narrow laterotergites to form deep submarginal rim; sublateral carina well developed on tergites, rarely absent ( Platyscelio striga ); no spiracles visible; sculpture on T1-T4 variable; S1 not laterally compressed; felt field absent.

Link to distribution map.

27 The genus Platyscelio is a widespread group throughout the Old World tropics, extending from West Africa to Queensland. Four species have relatively restricted distributions: Platyscelio arcuatus and Platyscelio striga (Western Australia), Platyscelio mysterium (Zimbabwe, Botswana, South Africa), and Platyscelio mzantsi (South Africa). Two species are widespread: Platyscelio africanus occurs in the Afrotropical realm from Senegal east to Yemen and south to South Africa; and Platyscelio pulchricornis is found in India and Southeast Asia east to Papua New Guinea and eastern Australia.

Key to species of Platyscelio

1Striae within ocellar triangle sparse (fewer than 20); distance between anterior ocellus and posterior ocellar line in frontal view greater than or equal to 0.5x POL (Figs. 17, 71)2-Striae within ocellar triangle dense (more than 20); distance between anterior ocellus and posterior ocellar line in frontal view less than 0.5x POL (Figs. 5, 11, 35, 41, 47, 59, 65)32Sculpture on T1 longitudinally striate, interstices with coriaceous microsculpture (Fig. 18); postmarginal vein absent (Fig. 16); notaulus with mesal margin arched, lateral margin straight (Fig. 15); legs beyond coxae yellow (Figs. 13, 14); female outer lateral apex of scape sharply pointed (Fig. 17) (Western Australia)Platyscelio arcuatus Taekul & Johnson, sp. n. -Sculpture on T1 longitudinally striate throughout (Fig. 72); postmarginal vein present, stumplike (Fig. 70); notaulus with both mesal and lateral margins arched (Fig. 69); legs beyond coxae brown (Figs. 67, 68); female outer lateral apex of scape bluntly rounded (Fig. 71) (South Africa)Platyscelio mzantsi Taekul & Johnson, sp. n. 3Frontal sculpture between inner orbit and central keel longitudinally striate, striae either extending through most of length of frons, or with few (4-5) striae restricted to upper half of frons (Figs. 23, 65)4-Frons between inner orbit and central keel smooth (Figs. 5, 11, 29, 35, 41, 47)54Mesoscutum with one lateral carina; notaulus absent (Fig. 21); sculpture on T1 longitudinally striate laterally, uniformly setigerous punctate medially (Fig. 22) (Botswana, South Africa, Zimbabwe)Platyscelio mysterium Taekul & Johnson, sp. n. -Mesoscutum with two lateral carinae; notaulus present (Fig. 63); sculpture on T1 longitudinally striate throughout (Fig. 64) (Western Australia)Platyscelio striga Taekul & Johnson, sp. n. 5Posterior scutellar sulcus complete (Figs. 3, 6, 9, 12); margin of propodeum longitudinally striate laterally, rugulose posteriorly (Figs. 6, 12); vertex between inner orbit and posterior ocellus densely striate (Figs. 5, 11) (sub-Saharan Africa, Yemen)Platyscelio africanus Risbec -Posterior scutellar sulcus interrupted medially (Figs. 27, 33, 39, 45, 57); margin of propodeum smooth laterally, longitudinally striate to rugulose posteriorly (Figs. 27, 33, 40, 48, 53, 57); vertex between inner orbit and posterior ocellus smooth (Figs. 29, 35, 41, 47, 51, 59) (India east to Guam, Solomon Islands, Vanuatu, eastern Australia)Platyscelio pulchricornis Kieffer