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 II: the Australian and southwest Pacific fauna, ZooKeys 331, pp. 1-266 : 5-21

Oxyscelio Kieffer

Oxyscelio Kieffer, 1907: 310. Original description. Type: Oxyscelio foveatus Kieffer, by monotypy.

Oxyscelio See Burks et al. (2013) for complete bibliography of the genus.

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 shape: 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 propo deum. 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: protruding anteriorly as short sharp extension of median longitudinal carina. Felt fields: absent. Ovipositor type: Scelio -type ( Austin and Field 1997).

Comments.

The genus is highly diverse and comprises in excess of 200 species worldwide. It has been recorded from Africa, the Indo-Malayan and eastern Palearctic regions ( Burks et al. 2013). Following this study, 80 species are known from Australasia and the southwest Pacific. The genus is found broadly across mainland Australia and Tasmania but not New Zealand. In the southwest Pacific it has been recorded from Papua New Guinea, New Britain, Vanuatu, Fiji, New Caledonia and Lord Howe Island.

Oxyscelio has been collected from a large range of habitats from rainforest, open dry forest, grasslands to more open, dry environments including the malle, semi-arid and arid zones 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 pan traps, even in closed habitats, indicating that many species may be living close to the ground.

Key to Australian and Oceanic species of Oxyscelio

Species groups of Australasian and Oceanic Oxyscelio

These groups are provided here to indicate intuitively perceived structure within the genus, and to provide an aid for identification. They are characterized in the above key and are diagnosed here in a succinct way. Some characters are omitted from certain species group diagnoses because those characters are variable within the group or are otherwise unhelpful for that particular group’s identification. Individual species descriptions can be consulted regarding characters omitted from these diagnoses.

Oxyscelio aciculae species group

Characteristics: Hyperoccipital carina absent or represented by weak rugae. Occipital carina complete or incomplete. Metascutellum nearly flat, subrectangular. Postmarginal vein present, strong. T1 lateral carina not expanded. Metasomal flanges absent. Main body of T6 in females not forming ledge above apical rim. T7 in males small, not or only weakly emarginate.

Comments: The aciculae-group contains long-bodied species with a narrower and flatter metascutellum than similarly-shaped species from Asia. An anterior T1 horn may be present or not. Metasomal depression sculpture, frontal depression depth and sculpture, and the presence of an outlined dorsal area of the occiput can be used to further subdivide these species. Some species in Asia and Africa also have an outlined, dorsally concave area of the occiput, but do not strongly resemble any species in this group in features of the face and metascutellum.

This group resembles the and catenae-group, concoloripes-group, and proceritatis-group in general habitus, but lack distinctive features present in those groups. The aciculae-group may be closely related to the flavipes-group, especially to species such as Oxyscelio tubi , but these groups are kept separate based on differences in the metascutellum.

Included species: Oxyscelio aciculae , Oxyscelio divisionis , Oxyscelio lintris , Oxyscelio pectinis , Oxyscelio productionis , Oxyscelio radii , Oxyscelio sciuri , Oxyscelio sinuationis , Oxyscelio stringerae .

Oxyscelio atricoxa species group

Characteristics: Hyperoccipital carina variable. Occipital carina complete medially. Metascutellum with a broad apical fovea and dorsally projecting posterior corners. Postmarginal vein absent or extremely short. T1 lateral carina expanded, visible from ventral view. Metasomal flanges present, or main body of T6 abruptly elevated above apical rim, in some species.

Comments: The atricoxa-group contains species that have either an expanded lateral T1 carina or a strongly sculptured area in its place (in which case distinct Metasomal flanges are present). While it is not convenient to lump distinctive species such as Oxyscelio mirellus with very generalized species such as Oxyscelio atricoxa , the fine gradient of variation between presence and absence of Metasomal flanges prevents any logical dividing line between these sets of species. No intuitive group containing Oxyscelio atricoxa is monophyletic in our analysis (Fig. 1), but we hypothesize that the presence of Metasomal flanges represents an apomorphic character. The limae-group from Sri Lanka and India resembles this group in body shape, and in that some members have apparent tiny Metasomal flanges, but they do not resemble the atricoxa-group in features of the metascutellum or T1.

Included species: Oxyscelio atricoxa , Oxyscelio bellariorum , Oxyscelio brevitas , Oxyscelio caudarum , Oxyscelio clivi , Oxyscelio clupei , Oxyscelio conjuncti , Oxyscelio contusionis , Oxyscelio cuspidis , Oxyscelio densitatis , Oxyscelio exiguitatis , Oxyscelio foliorum , Oxyscelio funis , Oxyscelio gressus , Oxyscelio hamorum , Oxyscelio hyalinipennis , Oxyscelio incisurae , Oxyscelio limbi , Oxyscelio liminis , Oxyscelio livens , Oxyscelio magniclava , Oxyscelio mirellus , Oxyscelio montanus , Oxyscelio nigriclava , Oxyscelio nigricoxa , Oxyscelio nitoris , Oxyscelio obturationis , Oxyscelio palati , Oxyscelio pollicis , Oxyscelio rami , Oxyscelio rupturae , Oxyscelio sarcinae , Oxyscelio sarcinae , Oxyscelio scismatis , Oxyscelio scutorum , Oxyscelio sordes , Oxyscelio stipulae , Oxyscelio tenuitatis , Oxyscelio truncationis , Oxyscelio umbonis , Oxyscelio uncinorum , Oxyscelio velamenti , Oxyscelio wa .

Oxyscelio catenae species group

Characteristics: Hyperoccipital carina indicated by rugae. Occipital carina complete, convex. Epomial corner sharp, protruding. Mesoscutum with raised longitudinal smooth area postero-medially. Postmarginal vein present. T1 lateral carina not expanded. Metasomal flanges absent. Main body of T6 in females not forming shelf above apical rim. T7 in males truncate or slightly emarginate apically, without protrusions.

Comments: The catenae-group encompasses two very similar Western Australian species that strongly differ from other Australian Oxyscelio . The distinctive mesoscutum and laterally protruding epomial corners aid in identification of this group.

Included species: Oxyscelio catenae , Oxyscelio valdecatenae .

Oxyscelio concoloripes species group

Characteristics: Hyperoccipital carina indicated by sharp rugae or carinae. Occipital carina variable. Metascutellum deeply concave, with broad posterior fovea. T1 lateral carina not expanded. Postmarginal vein absent or nearly so. Metasomal flanges absent. Main body of T6 not forming ledge above apical rim. T7 in males truncate or nearly so.

Comments: The concoloripes-group contains a pair of species that are somewhat similar to the aciculae-group and flavipes-group, but which do not have a simple hyperoccipital carina and do not have a strongly developed postmarginal vein. Both included species can have mostly or entirely dark brown bodies, but this feature is variable in Oxyscelio verrucae and is present in some other species that are not otherwise similar to these species.

Included species: Oxyscelio concoloripes , Oxyscelio verrucae .

Oxyscelio dasymesos species group

Characteristics: Hyperoccipital carina indicated by rugae. Occipital carina absent medially. Metascutellum concave dorsally. Postmarginal vein present. Metasomal depression setose. T1 lateral carina not expanded. Metasomal flanges absent. Main body of T6 in females not separated from apical rim. T7 in males weakly emarginate.

Comments: The otherwise Asian dasymesos-group has one known Australian species. This group is distinct in having a setose metasomal depression.

Included species: Oxyscelio lenitatis .

Oxyscelio flavipes species group

Characteristics: Hyperoccipital carina sharply indicated (exceptions: Oxyscelio circulorum , Oxyscelio tubi , Oxyscelio viator ). Occipital carina absent medially, but without strong lateral corners. Metascutellum concave dorsally, with broad apical fovea. Postmarginal vein present, well-developed. T1 lateral carina not expanded (exception: some Oxyscelio obliquiatis ). Metasomal flanges absent. Main body of T6 in females not separated from apical rim. T7 in males truncate or weakly emarginate, without projections.

Comments: The flavipes-group is a major group that is limited to Australia and the Pacific Islands. In having a strong hyperoccipital carina, it resembles the Asian cuculli-group, but differs from it in having an incomplete occipital carina in which the lateral branches closely approach the hyperoccipital carina dorsally. These two groups otherwise resemble each other in having a relatively fusiform metasoma. Some species in this group, especially Oxyscelio tubi , resemble some in the aciculae-group, but are placed here because of metascutellar features.

Included species: Oxyscelio bicoloripedis , Oxyscelio circulorum , Oxyscelio croci , Oxyscelio flavipes , Oxyscelio fluctuum , Oxyscelio obliquiatis , Oxyscelio oblongiclypei , Oxyscelio oculi , Oxyscelio rugulosus , Oxyscelio sepisessor , Oxyscelio tubi , Oxyscelio viator .

Oxyscelio fossarum species group

Characteristics:Hyperoccipital carina absent or represented by weak rugae. Occipital carina incomplete medially, with strong lateral corners. Metascutellum nearly flat. Postmarginal vein present. T1 lateral carina not expanded. Metasomal flanges absent. T2 with sublateral depressions, set off by carinae medially. Main body of T6 in females not separated from apical rim. T7 in males weakly emarginate apically.

Comments: The mostly Asian fossarum-group has one known Australian species. This group is very different from most other Australian Oxyscelio , only resembling some members of the aciculae-group and proceritatis-group.

Included species: Oxyscelio solitarius .

Oxyscelio foveatus species group

Characteristics: Hyperoccipital carina absent or represented by weak rugae. Occipital carina incomplete medially, with strong lateral corners. Lower face, between antennal insertion and eye, with oblique flange-like expansion. Metascutellum nearly flat. Postmarginal vein present. T1 lateral carina not expanded. Metasomal flanges absent. Main body of T6 in females not separated from apical rim.

Comments: Most known species of the foveatus-group occur in Asia. This group may not be monophyletic, being united mainly by the presence of the oblique facial flange and a long body, but splitting it would result in many small species groups that would ultimately be no better supported. The Philippine species Oxyscelio cupularis (Kieffer) is very similar to the three species discussed here.

Included species: Oxyscelio anfractus , Oxyscelio linguae , Oxyscelio mystacis .

Oxyscelio proceritatis species group

Characteristics: Hyperoccipital carina indicated by weak rugae. Occipital carina absent medially. Gena posteroventrally smooth and glossy. Lower face without oblique flange between antennal insertion and eye. Metascutellum very broad, rugose. Postmarginal vein present. T1 lateral carina not expanded. T2 without sublateral depressions. Metasomal flanges absent. Main body of T6 in females not separated from apical rim. T7 in males weakly emarginate apically.

Comments: These two species resemble the Asian latitudinis-group in having a broad, rugose metascutellum and a long body. They differ in having a weakly sculptured head, including the posteroventrally smooth gena. They are kept separate from the latitudinis-group because of these differences.

Included species: Oxyscelio corrugationis , Oxyscelio proceritatis .

Species not placed to group

Included species: Oxyscelio dissimulationis , Oxyscelio grandis , Oxyscelio nasi , Oxyscelio shakespearei , Oxyscelio spatulae .

Comments: Oxyscelio dissimulationis and Oxyscelio shakespearei possess features of both the atricoxa-group and flavipes-group, and are therefore problematic. Oxyscelio nasi is somewhat similar to the flavipes-group, but lacks all distinctive features of that group. Oxyscelio spatulae is similar to some species of the foveatus-group, but lacks oblique facial flanges.The holotype of Oxyscelio grandis is incomplete, and does not provide enough information to place it into a species group.