Oxyscelio Kieffer

Burks, Roger A., Masner, Lubomir, Johnson, Norman F. & Austin, Andrew D., 2013, Systematics of the parasitic wasp genus Oxyscelio Kieffer (Hymenoptera, Platygastridae s. l.), Part I: Indo-Malayan and Palearctic fauna, ZooKeys 292, pp. 1-263 : 4-12

Oxyscelio Kieffer

Oxyscelio Kieffer, 1907: 310. Original description. Type: Oxyscelio foveatus Kieffer, by monotypy; Brues 1908: 46 (diagnosis, list of species); Kieffer 1910b: 62, 68 (description, key to subgenera, keyed); Kieffer 1913a: 224 (description); Kieffer 1926: 261, 267 (description, keyed, key to species); Dodd 1931: 72 (diagnosis, synonymy, list of species, key to related groups); Mani 1941: 25 (catalog of species of India); Muesebeck and Walkley 1956: 377 (citation of type species); Masner 1976: 22, 25 (description, keys to separate Baryconus Foerster, Bacalba Dodd, Chromoteleia Ashmead, Oxyscelio Kieffer); De Santis 1980: 311 (catalog of species of Brazil); Galloway and Austin 1984: 7, 8, 13 (list of species described from Australia, keyed); Johnson 1992: 451 (catalog of world species); Austin and Field 1997: 18, 68 (structure of ovipositor system, discussion of phylogenetic relationships, genus misplaced in Baryconini ); Lê 2000: 32, 39 (keyed, description); Rajmohana 2006: 116 (keyed); Kononova and Fursov 2007: 61 (description); Kononova and Fursov 2007: 103 (description); Kononova and Kozlov 2008: 21, 190 (description, keyed, key to species of Palearctic region).

Dicroteleia Kieffer, 1908: 92. Original description. Type: Dicroteleia rugosa Kieffer, by monotypy. Synonymized by Dodd (1931); Kieffer 1926: 267, 387 (description, keyed, key to species); Mani 1941: 25 (catalog of species of India); Muesebeck and Walkley 1956: 346 (citation of type species); Baltazar 1966: 179 (catalog of species of the Philippines).

Chromoteleia ( Oxyscelio ): Kieffer 1910a: 312 (key to species, keyed); Kieffer 1910b: 68, 69 (description, list of species, keyed).

Oxyscelio ( Dicroteleia ): Kieffer 1910b: 68 (description, list of species, keyed).

Camptoteleia Kieffer, 1913b: 387. Original description. Type: Camptoteleia carinata Kieffer, designated by Kieffer (1926) (key to species of the Philippines). Synonymized by Dodd (1931); Kieffer 1914: 296 (key to species of the Philippines); Kieffer 1916: 64, 171 (key to new species described from the Philippines); Kieffer 1926: 267, 379 (description, keyed, key to species); Baltazar 1966: 177 (catalog of species of the Philippines).

Xenoteleia Kieffer, 1913b: 390. Original description. Type: Xenoteleia flavipennis Kieffer, by monotypy and original designation. Synonymized by Dodd (1931); Kieffer 1926: 270, 427 (description, keyed); Muesebeck and Walkley 1956: 408 (citation of type species); Baltazar 1966: 181 (catalog of species of the Philippines).

Description.

Body length: 2.6-7.1 mm.

Head shape in dorsal view: weakly transverse, width approximately 1.5x greatest length; subquadrate. Hyperoccipital carina: absent; present. Occipital carina: present, complete medially; present, broadly interrupted medially. Occipital carina sculpture: crenulate. Ocular ocellar line (OOL): OOL <0.5 ocellar diameter (OD). Dorsal area of frons: convex, without frontal shelf. Antennal scrobe shape: present, unmargined; scrobe margined by carina. Frons sculpture: umbilicate-punctate, with transverse carinae within scrobe; scrobe largely smooth, otherwise with transverse carinae. Submedian carina: absent. Orbital carina: absent. Inner orbits: diverging ventrally. Interocular space(IOS)/Eye height (EH): IOS distinctly less than EH. Interantennal process: triangular in lateral view. Central keel: absent. Antennal foramen opening: oriented laterally on interantennal process. Facial striae: present. Malar sulcus: present. Compound eye size: not significantly reduced. Compound eye setation: absent. Gena: weakly convex, receding behind posterior orbit; convex, distinctly produced behind eye. Clypeus shape: narrow, slightly convex medially, lateral corner not produced. Apical margin of clypeus: with small median point. Labrum: not visible. Mandibular teeth: apex with 2, acute, subequal teeth. Arrangement of mandibular teeth: transverse. Number of maxillary palpomeres: 4. Shape of maxillary palpomeres: cylindrical. Number of labial palpomeres: 2.

Number of antennomeres in female: 12. Number of antennomeres in male: 12. Insertion of radicle into A1: parallel to longitudinal axis of A1. Shape of A1: more or less cylindrical, not flattened. Length of A3 of female: subequal to length of A2; distinctly longer than A2. Number of clavomeres in female antenna: 7; 0. Claval formula of female antenna: A12-A7/1-2-2-2-2-1; A12-A6/1-2-2-2-2-2-2. Arrangement of doubled multiporous plate sensilla on female clava: in longitudinal pairs. Tyloid distribution on male antenna: A5 only. Shape of male flagellum: filiform.

Mesosoma shape in dorsal view: longer than wide. Mesosoma shape in lateral view: longer than high. Medial portion of transverse pronotal carina: weakly indicated laterally; absent. Posterior apex of pronotum in dorsal view: straight, bifid apically to articulate with tegula. Vertical epomial carina: present. Dorsal epomial carina (lateral portion of transverse pronotal carina of Vilhelmsen et al. 2010): present. Anterior face of pronotum: oblique, visible dorsally, short. Lateral face of pronotum: deeply concave below dorsal pronotal superhumeral sulcus. Netrion: present. Netrion shape: open ventrally. Anterior portion of mesoscutum: vertical, flexed ventrally to meet pronotum. Mesoscutum shape: pentagonal in dorsal view, posterolateral corner rounded. Skaphion: absent. Notaulus: present, percurrent. Parapsidal lines: present; absent. Anteroadmedial lines: present. Scutoscutellar sulcus: well-developed, narrow. Shape of mesoscutellum: quadrate to trapezoidal. Armature of mesoscutellum: absent. Surface of mesoscutellum: convex throughout. Median longitudinal furrow on mesoscutellum: absent. Shape of axillula: small, dorsal margin sinuate. Metascutellum: clearly differentiated. Metascutellar armature: produced medially into short, shallowly bidentate process; produced into broad flattened plate; produced into narrow, flat, apically blunt process. Metascutellar setation: absent; present dorsally and ventrally. Extent of metasomal depression of propodeum: percurrent, extending anteriorly to anterior margin of propodeum. Lateral propodeal projection: well-developed, extending clearly beyond anterior margin of T1. Mesopleural carina: present across sclerite; absent or strongly abbreviated, present only near mid coxa. Mesal course of acetabular carina: projecting as small spur anteriorly, not long enough to intercede between fore coxae. Mesopleural pit: absent. Sternaulus: absent. Posterodorsal corner of mesopleuron: rounded anteriorly.

Number of mid tibial spurs: 1. Number of hind tibial spurs: 1. Dorsal surface of hind coxa: smooth. Hind tibia shape: cylindrical, ecarinate. Trochantellus: present.

Wing size of female: macropterous. Wing size of male: macropterous. Tubular veins in fore wing: present. Bulla of fore wing R: absent. Extent of marginal venation of fore wing: R1 reaching and ending at costal margin; distinct marginal or postmarginal veins present. Origin of r-rs in fore wing: arising before (basad of) R/R1 attains costal margin. Structure of basal vein (Rs+M) in fore wing: spectral. Structure of R in hind wing: elongate, extending to costal margin; abbreviated, not attaining costal margin.

Number of externally visible terga in female: 6. Number of externally visible sterna in female: 6. Number of externally visible terga in male: 8. Number of externally visible sterna in male: 7. Shape of metasoma: acuminate, widest submedially. Laterotergites: present, narrow. Laterosternites: present. T1 of female: raised medially into low, rectangular or subelliptical platform, laterally depressed. Relative size of metasomal segments: T2 distinctly largest; T2 and T3 distinctly larger, subequal in size. Terga with basal crenulae: T1, T2. Sublateral carinae on tergites: present on T1. Median longitudinal carina on metasomal terga: absent. Shape of female T6: flattened. Shape of posterior margin of male T7: straight; incised medially. Anterior margin of S1: pro truding anteriorly as short sharp extension of median longitudinal carina. Felt fields: absent. Ovipositor type: Scelio -type ( Austin and Field 1997).

Comments. Oxyscelio is a very distinctive genus particularly because of the morphology of the face, vertex and fore wing venation. The genus is highly diverse and comprises in excess of 200 species. It has been collected from a large range of habitats from rainforest, open dry forest, grasslands to more open, dry environments including the malle and semi-arid zone of Australia. Species have been collected using a variety of standard collecting techniques for small parasitic Hymenoptera , but they can be particularly numerous in yellow pantraps, even in closed habitats, indicating that many species may be living close to the ground.

Biology. Although there are a large number of species known from Asia and Australia there are apparently no available rearing records from hosts identified beyond ordinal level (see Kononova and Fursov 2007, for photograph of egg of orthopteran host of Oxyscelio perpensus Kononova). However, given the large size of most species, the diversity of habitats in which they have been collected, and the structure of the ovipositor, we presume that all Oxyscelio species parasitise orthopteran eggs of some type.

Distribution. Oxyscelio has been recorded from Africa (Cameroon, Central African Republic, Democratic Republic of the Congo, Côte d’Ivoire, Gabon, Ghana, Guinea, Kenya, Malawi, Nigeria, Rwanda, Sierra Leone, Somalia, Tanzania, Togo, Uganda), the Indo-Malayan region (Brunei, Christmas Island, India, Indonesia, Laos, Malaysia, Philippines, Singapore, Sri Lanka, Taiwan, Thailand, Vietnam), the eastern Palearctic (mainland China, Japan, Nepal, South Korea), Australasia and the south-west Pacific (mainland Australia, Tasmania, Fiji, Lord Howe Is., New Britain, New Caledonia, Papua New Guinea, Solomon Islands, Vanuatu).

Phylogenetic relationships. Masner (1976) postulated that Oxyscelio is related to Bracalba Dodd, Chromoteleia Ashmead and Baryconus Foerster, and he provided a key to separate them. Based on the structure of the ovipositor system it is unlikely that Baryconus is related to this group of genera given it has a Ceratobaeus -type system, where the other genera all have a Scelio type ovipositor system ( Austin and Fields 1997). The molecular phylogenetic study of Murphy et al. (2007) included three of these genera, Oxyscelio , Chromoteleia and Baryconus , and none showed a sister-group relationship to each other, although the support on the branches that linked these genera were far from robust. Two of us (NFJ and ADA) are currently coordinating a significantly expanded molecular analysis of the Platygastroidea involving additional sequence data and a trebling of taxa, and this should help resolved the relationships among these and other genera.

The species level phylogeny generated as a part of this study (Fig. 1) does not always uphold monophyly of the species groups described below. The authors do not see this as a major problem, as the species groups are informal groupings that are not necessarily meant to be strictly monophyletic. They are meant to be useful for species diagnostics, but can be seen as potentially valid alternatives to the included phylogeny.

Species Groups of Oxyscelio

For the Indo-Malayan and Palearctic fauna of Oxyscelio we recognize 13 species groups. These groups are discussed below to indicate intuitively our perception of the structure within the genus and to serve as an aid in specimen identification.

Oxyscelio carinatus Species Group

Characteristics: Frontal depression flat or nearly so. Hyperoccipital carina complete as a strong ruga, continuous with the anteriormost genal carina, laterally not connected with occipital carina. Occipital carina complete or incomplete, but without strong lateral corners. Metascutellum with a pair of subapical dorsal setae, concave dorsally, slightly emarginate apically with rounded posterolateral lobes. T7 in males with acuminate posterolateral corners.

Comments: The carinatus-group is very similar to the cuculli-group, but differs in that the hyperoccipital carina is defined by a ruga and in having a deeper frontal depression. The Oxyscelio mesiodentis -complex within the cuculli-group has a much more densely setose and differently shaped metascutellum than in the carinatus-group. The general trend towards sculptural reduction in Philippine species (a more pronounced reduction occurs in species from the Maluku Islands of Indonesia) leads one to consider the possibility that the carinatus-group could be weakly sculptured species of the cuculli-group. However, it does not seem proper to lump these groups without additional data supporting this hypothesis. Another possibility exists, that the carinatus-group could be closely related to the dasymesos-group, as both groups contain species with a setose metascutellum and nearly flat frontal depression.

Includes: Oxyscelio carinatus , Oxyscelio praecipitis , Oxyscelio spinosiceps , Oxyscelio vittae .

Oxyscelio crateris Species Group

Characteristics: Hyperoccipital carina complete, continuous with the anteriormost genal carina, laterally connected with occipital carina by a distinct longitudinal carina or elevation; area between hyperoccipital and occipital carinae slightly sunken and crater-like. Metascutellum about as long as broad, concave dorsally and with little or no median sculpture, rounded apically. T7 in males without posterolateral spines.

Comments:The crateris-group contains a few species with a crater-like area, between the occipital and hyperoccipital carinae, that is fully outlined by carinae. This area also has distinctive sculpture that is different from that of surrounding areas. Some members of the latitudinis-group may have a similarly weakly concave or partially outlined crater-like area as well, but these species have a very different, broad and strongly sculptured metascutellum.

Includes: Oxyscelio cordis , Oxyscelio crateris , Oxyscelio spinae .

Oxyscelio crebritas Species Group

Characteristics: Hyperoccipital carina absent or weakly indicated by rugae, laterally not connected with occipital carina. Occipital carina complete or incomplete, but without strong lateral corners. Frons without oblique flange; frontal depression without transverse carinae or grooves in ventral half. Metascutellum medially concave and smooth or with transverse carinae. T7 in males usually with sharp posterolateral corners, rarely with short spines or without spines.

Comments:The crebritas-group contains many very similar species differing in subtle ways. Most members of this group have a radicle that is darker than the scape, but this feature is variable in many species. The florus-group differs in having longitudinal metascutellar rugae, instead of transverse carinae. The noduli-group is similar but has a much more strongly sculptured frontal depression.

Includes: Oxyscelio amrichae , Oxyscelio asperi , Oxyscelio brevinervis , Oxyscelio capilli , Oxyscelio capitis , Oxyscelio codae , Oxyscelio consobrinus , Oxyscelio crebritas , Oxyscelio excavatus , Oxyscelio genae , Oxyscelio granuli , Oxyscelio jugi , Oxyscelio kiefferi , Oxyscelio lacunae , Oxyscelio longiventris , Oxyscelio mollitia , Oxyscelio reflectens .

Oxyscelio cuculli Species Group

Characteristics: Hyperoccipital carina complete and strong, continuous with the anteriormost genal carina, laterally not connected with occipital carina. Occipital carina complete or incomplete, but without strong lateral corners. Metascutellum concave dorsally and with little or no median sculpture, incised or slightly emarginate apically. T7 in males variable, some species with strong posterolateral spines.

Comments: The cuculli-group has several distinctive species with a sharp hyperoccipital carina and strongly concave frontal depression that is more or less hood-like. There are some other species that possess these traits in less-developed ways, but which can be linked with this group through transformation series. These species make distinction from the crebritas-group and carinatus-group especially difficult. Because of this, it is useful to divide this group into three species complexes that can be more consistently defined:

Oxyscelio convergens Species Complex: Metascutellum long, weakly emarginate, nearly flat, not setose. Anterior portion of metasomal depression long and exposed dorsally; with long and narrowly separated lateral propodeal carinae, often with a median carina between them. Includes: Oxyscelio aureamediocritas , Oxyscelio bipunctuum , Oxyscelio convergens , Oxyscelio kramatos , Oxyscelio marginalis , Oxyscelio vadorum .

Oxyscelio cuculli Species Complex: Metascutellum short, strongly emarginate with dorsally protruding posterolateral corners, not setose. Anterior portion of metasomal depression short and weakly developed, hidden from dorsal view; lateral propodeal carinae short and variably separated anteriorly. Includes: Oxyscelio angustifrons , Oxyscelio cuculli , Oxyscelio granorum , Oxyscelio intermedietas , Oxyscelio nubbin .

Oxyscelio mesiodentis Species Complex: Metascutellum setose dorsally, weakly emarginate and nearly flat. Anterior portion of metasomal depression short, variably sculptured. Includes: Oxyscelio arcus , Oxyscelio brevidentis , Oxyscelio ceylonensis , Oxyscelio crassicornis , Oxyscelio crustum , Oxyscelio doumao , Oxyscelio mesiodentis , Oxyscelio unguis .

Oxyscelio dasymesos Species Group

Characteristics: Hyperoccipital carina incomplete or indicated by poorly defined rugae, laterally not connected with occipital carina. Occipital carina complete or incomplete, but without strong lateral corners. Metasomal depression setose. T7 in males with acuminate posterolateral corners.

Comments:A setose metasomal depression does not occur in any other Asian species of Oxyscelio . The dasymesos-group is otherwise difficult to compare with other Oxyscelio species groups, but it bears some general resemblance to the carinatus-group and crebritas-group.

Includes: Oxyscelio dasymesos , Oxyscelio dasynoton .

Oxyscelio florus Species Group

Characteristics: Hyperoccipital carina absent or indicated by poorly defined rugae, laterally not connected with occipital carina. Occipital carina complete or incomplete, but without strong lateral corners. Frons without oblique flange. Metascutellum with longitudinal rugae and without any strong transverse carinae. T2 without longitudinal depressions or strong curved striae.

Comments:The florus-group contains species that are similar to the crebritas-group in having a dark radicle and uniformly curved occipital carina, but differ in having a rugose metascutellum and a generally longer metasoma. The latitudinis-group is also similar to this group based on most of the above-mentioned features, but differs in having an occipital carina with strong lateral corners.

Includes: Oxyscelio arvi , Oxyscelio dermatoglyphes , Oxyscelio florus , Oxyscelio jaune , Oxyscelio regionis .

Oxyscelio fossarum Species Group

Characteristics: Hyperoccipital carina incomplete or indicated by weak rugae. Occipital carina with sharp protruding lateral corners. T2 with long sublateral depressions.

Comments:The fossarum-group is similar to the foveatus-group, latitudinis-group, and striarum-group, but is distinguished by the T2 depressions that occur in females (and in males of some species). These groups differ in metascutellar form as well, with the fossarum-group having a generally narrower metascutellum. The defining feature of this group can be difficult to discern, but is best verified by finding the strong medial borders of the depressions.

Includes: Oxyscelio aclavae , Oxyscelio acutiventris , Oxyscelio cyrtomesos , Oxyscelio fistulae , Oxyscelio fodiens , Oxyscelio fossarum , Oxyscelio fossularum , Oxyscelio rugosus , Oxyscelio zeuctomesos .

Oxyscelio foveatus Species Group

Characteristics: Hyperoccipital carina incomplete or indicated by weak rugae. Occipital carina with strong lateral corners. Ventral frons with oblique flange. Metascutellum tiny and concave, or broad and convex, or elongate with a smooth channel. T2 without longitudinal depressions or strong curved striae.

Comments:The foveatus-group likely is a non-monophyletic group containing species with an oblique facial flange and an occipital carina with protruding lateral corners, but with none of the defining features of some other species groups. Species with longitudinal T2 depressions, but which would otherwise agree with this group, have been placed in the fossarum-group.Other species with an oblique facial flange occur in the carinatus-group, crateris-group,and cuculli-group, but differ strongly from these species.

Includes: Oxyscelio angustinubbin , Oxyscelio cupularis , Oxyscelio foveatus , Oxyscelio greenacus , Oxyscelio latinubbin , Oxyscelio nasolabii , Oxyscelio operimenti .

Oxyscelio latitudinis Species Group

Characteristics:Lower frons without oblique flange. Hyperoccipital carina incomplete or indicated by weak rugae. Occipital carina with sharp protruding lateral corners. Metascutellum broad, almost always rugose. T2 without sublateral depressions or strong curved striae.

Comments:The latitudinis-group is essentially negatively defined among Oxyscelio that have strong lateral corners of the occipital carina. The best distinctive feature of this group is the broad, rugose metascutellum of most species, but a few have a narrower metascutellum that more closely approaches that of the fossarum-group. Most members of this group have a metallic green luster, but this is lost in some specimens. Except where noted in species descriptions, color seems to be a highly unreliable character for identification of Oxyscelio .

Includes: Oxyscelio dorsalis , Oxyscelio latitudinis , Oxyscelio naraws , Oxyscelio peludo , Oxyscelio perpensus .

Oxyscelio limae Species Group

Characteristics: Hyperoccipital carina incomplete or weakly indicated by rugae. Occipital carina complete medially, without sharp protruding lateral corners. Mesoscutum anteriorly very steep. Postmarginal vein absent. Metascutellum variable but without dorsally protruding posterolateral corners.

Comments:The limae-group contains species from India and Sri Lanka, all with a strongly elevated and anteriorly steep mesoscutum. These species strongly resemble the crebritas-group, but differ in having very short fore wing venation with no sign of a postmarginal vein. Some Australian species, including Oxyscelio montanus (Dodd) strongly resemble this group, but differ in having a short metascutellum with dorsally protruding posterolateral corners. Tiny but sharp and slightly protruding posterolateral corners of T4 or T5 in females of Oxyscelio limae and Oxyscelio anguli indicate that the limae-group may be the closest relative of an otherwise Australian clade containing Oxyscelio montanus and Oxyscelio mirellus (Dodd).

Includes: Oxyscelio anguli , Oxyscelio flaviventris , Oxyscelio limae .

Oxyscelio noduli Species Group:

Characteristics: Hyperoccipital carina absent or weakly indicated by rugae, laterally not connected with occipital carina. Occipital carina complete, but without strong lateral corners. Frons without oblique flange; frontal depression crossed by many carinae. Metascutellum medially concave and smooth.

Comments:The noduli-group contains some species that are resemble the latitudinis-group in metasomal length and frontal depression sculpture, but which have a small and medially smooth metascutellum and an occipital carina without strong lateral corners. The latter features are similar to those in the crebritas-group, and therefore these species may be phylogenetically intermediate between that group and the latitudinis-group. Alternatively, they may be reduced apomorphic members of the latitudinis-group.

Includes: Oxyscelio chimaerae , Oxyscelio nodorum , Oxyscelio noduli .

Oxyscelio ogive Species Group

Characteristics: Hyperoccipital carina incomplete or indicated by rugae. Occipital carina complete medially, but with sharp lateral corners and concave medial sections that meet at a median peak.

Comments:Members of the ogive-group superficially resemble the crebritas-group, but differs in the sinuate occipital carina with sharp lateral corners. It differs from the latitudinis group in having a sharp and rounded submedian carina.

Includes: Oxyscelio cavinetrion , Oxyscelio flabelli , Oxyscelio labis , Oxyscelio ogive , Oxyscelio sinuum .

Oxyscelio striarum Species Group

Characteristics:Hyperoccipital carina incomplete or indicated by rugae. Occipital carina with sharp lateral corners. Metascutellum rugose. T2 (at least) in females with strong curved longitudinal striae submedially that flank a triangular area without striae.

Comments:The striarum-group is similar to the latitudinis-group, but differs in the strong curved striae of T2 and T3 in females. Males may be difficult to recognize, because those of Oxyscelio caesitas reveal that they do not possess these strong striae. They do have slightly more distinct sublateral striae of S2 and S3, but these striae are straight and do not distinctly differ from those of other species groups.

Includes: Oxyscelio caesitas , Oxyscelio striarum .

Species unplaced to group

Oxyscelio flavipennis , Oxyscelio halmaherae , Oxyscelio magnus , Oxyscelio obsidiani , Oxyscelio planocarinae , Oxyscelio tecti .

Key to Indo-Malayan and eastern Palearctic species of Oxyscelio