Archaeoscelio Brues, 1940

MASNER, LUBOMÍR, JOHNSON, NORMAN F. & POLASZEK, ANDREW D., 2007, Redescription of Archaeoscelio Brues and Description of Three New Genera of Scelionidae (Hymenoptera): A Challenge to the Definition of the Family, American Museum Novitates 3550 (1), pp. 1-24 : 3-6

Archaeoscelio Brues figures 1–12

Archaeoscelio Brues, 1940: 88 . Original description. Type: Archaescelio rugosus Brues , by original designation. For subsequent taxonomic literature, see Johnson (1992).

DISTRIBUTION: Baltic amber.

DESCRIPTION: Length: 1.2–2.2 mm. Body robust, compact; head and metasoma closely appressed to mesosoma. Head moderately transverse ( fig. 5 ); hyperoccipital carina absent ( figs. 4 , 7, 9 ); occipital carina hidden dorsally; vertex and frons coarsely areolaterugose ( figs. 2, 5 , 12 ); lateral ocellus variable in position, equidistant between median ocellus and inner orbit ( fig. 9 ) or separated from inner margin by at most one ocellar diameter ( fig. 4 ); frons convex, without distinct antennal scrobe, medial carina absent; interantennal process weakly produced anteriorly; submedial carina absent; orbital carina absent; cheek above mandible without fanlike striae; eye setae absent or indistinct; interocular space broad, approximately equal to eye height; inner orbits parallel to subparallel, not diverging ventrally; torulus contiguous with upper margin of clypeus, opening ventrally, rim produced dorsally and medially, overhanging antennal articulation; postclypeus strongly transverse, flat; anteclypeus elongate, longer than postclypeus; malar sulcus absent ( A. rugosus , figs. 1–3, 5 ) or present ( A. filicornis , figs. 8, 10, 12 ); gena convex, areolate-rugose, without antennal depression; mandible massive, tridentate; mandibular teeth arrayed transversely, deeply incised, acute; maxillary palpus four-segmented, segment 2 weakly expanded medially; labial palpus not observable; female antenna with 14 antennomeres ( figs. 3, 4 , 10, 12 ), male antenna with 14 antennomeres ( figs. 5 , 7, 9 ); longitudinal axes of radicle and scape nearly perpendicular to one another ( fig. 5 ); scape more or less cylindrical, weakly expanded medially, weakly excavate dorsally for reception of pedicel and base of flagellum; female A3 not distinctly elongate, slightly longer than A2; female antenna with nonabrupt clava composed of 8–10 antennomeres; claval formula 1-2-2-2-2-2-1; male sex segment not apparent.

Mesosoma ( figs. 25, 26 , 31, 32 ) short, squat, about as high as wide, viewed from above nearly quadrate; pronotum, in dorsal view, abruptly truncate anteriorly, anterolateral corners sharply pointed, not protruding anteriorly; transverse pronotal carina present ( figs. 1, 4 ); pronotal humeral carina present; dorsal surface of pronotum coarsely areolate; anterior face of pronotum nearly vertical; lateral surface of pronotum convex above, coarsely areolate, deeply concave below, longitudinally costate; epomial carina present, extending ventrally to forecoxa; netrion/epicnemium linear ( figs. 2 , 12 ); pronotal–mesoscutal suture concave laterally ( figs. 4 , 9 ), exposing large dorsal surface of pronotal humeri; anterior margin of mesoscutum meeting pronotum dorsally ( figs. 4 , 7 ); mesoscutum trapezoidal, moderately convex, anteriormost point broadly separated from transverse pronotal carina; skaphion absent; notauli and parapsidal lines absent; mesoscutum coarsely areolate; transscutal articulation very broad, deep; scutellum triangular, strongly convex, coarsely areolate, medially elongate, apex weakly bidentate ( figs. 4, 6 , 11 ), anterior margin with deep lacunae; axilla clearly defined; dorsellum in form of simple, central swelling; propodeum not visible dorsally, posterior surface vertical, setation not observable; mesopleuron not narrowed, mesepisternum and mesepimeron not differentiated by suture or line of foveae; mesopleural depression shallow, mesopleural pit absent; mesopleural carina present, flanked on both sides by large areolae; upper mesepisternum coarsely areolate rugose; sternaulus not developed; anterior margin of ventral portion of mesepisternum strongly extended anteriorly between forecoxae ( fig. 2 ); posterodorsal corner of mesopleuron rounded; mesopleuron and metapleuron separated by distinct suture ( figs. 1, 3 , 12 ); metapleuron large, rectangular, posterior margin straight, sparsely setose throughout; metapleural pit absent; upper angles of posterior margin of metapleuron weakly produced; propodeum with anterodorsal face setose; posterolateral corners of propodeum strongly produced posteriorly ( figs. 3 , 12 ); legs relatively slender; posterior surface of hindcoxa smooth; trochantellus present on all legs; hindfemur weakly enlarged apically, without lamellae flanking base of tibia; tibial spur formula 1-1-1; tarsi 5-5-5, tarsomeres gradually tapering in width toward apex; pretarsal claws small, simple; forewing ( figs. 6 , 9–11 ) very broad, marginal cilia short; R (submarginal vein) tubular, pigmented, rather short, not extending beyond basal half of wing, distinctly remote from costal margin, width of cell gradually expanding apically; no bulla in R basad of apical fork; R 1 very short, not reaching wing margin as tubular vein; r-rs longer but ending blindly as tubular vein; Rs extending beyond apical fork as nearly straight nebulous vein to costal margin; first free segment of M (basal vein) present as nebulous vein, arising perpendicular to R; hindwing shape not clearly observable in available specimens; R tubular, not observable basally, apically gradually fusing with margin, without distinct angle, marginal vein short; with three hamuli at wing margin.

Metasoma robust, moderately elongate, broadly sessile, laterally without sharp edge or submarginal groove; female ( figs. 3 , 10, 12 ) with six visible terga, five sterna; male ( figs. 1 , 8 ) with seven visible terga, six sterna; laterotergites, laterosternites absent ( figs. 1, 3 , 10, 12 ); terga moderately convex; sterna strongly convex; lateral margins of terga slightly overlapping over upper margins of sterna; terga 1–4 with strongly raised sublateral keels, coarsely sculptured; terga and sterna with basal margins crenulate; T1 moderately transverse, longer than other terga; T2 transverse, coarsely areolate; T6 details not observable; terga beyond T6 not observable; S1 ( figs. 2 , 10, 12 ) very deep, strongly convex, anteromedial portion with sharp median keel extending anteriorly between hindcoxa, coxae fitting into basal depressions in sternite; anterior margin of S2 straight; metasomatic felt fields absent; S5 not observed; ovipositor not observable.

DIAGNOSIS: Antenna 14-segmented; tibial spur formula 1-1-1; clava 7-merous, claval formula 1-2-2-2-2-2-1; male A5 not visibly modified; submarginal vein elongate, tubular, apically forked, but not reaching costal margin.

RELATIONSHIPS: Archaeoscelio generally has not been included in discussions of scelionid relationships, except to note that the 14-segmented antennae are a plesiomorphic feature. In his original description, Brues (1940) expressed doubts as to whether Archaeoscelio was correctly placed within the Scelionidae . He noted a similarity in habitus and the structure of the mandibles with Chalcidoidea, but stated that ‘‘the wing venation is not in close conformity with that of any group known to me’’ ( Brues, 1940: 90). The similarity in the mouthparts is, presumably, the fact that the mandibles are large, fairly robust, and bear sharply pointed apical teeth. However, the number and shape of mandibular teeth are extremely variable in both superfamilies, and these characters are commonly used to distinguish among closely related species.

It is indeed difficult to understand the venation on the basis of Brues’s published drawings. One problem is that the illustrations fail to distinguish between folds, simple lines of pigmentation (nebulous veins), tubular veins, and artifacts. The veins are also a bit distorted and appear more angular than they are in the fossils or in living scelionids. The true venation is striking in that the submarginal vein does not reach the costal margin of the wing and has an apical bifurcation. A similar configuration, although with the apical branches very much shorter, may be seen in basal platygastrid genera such as Proplatygaster Kieffer ( fig. 41 ) and Metaclisis Förster ( Masner and Huggert, 1989), as well as in the new genera Huddlestonium ( fig. 39 ) and Cobaloscelio ( fig. 18 ).

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Figures

Figs. 1–6. Archaeoscelio rugosus Brues. 1, Holotype male, lateral habitus. 2, Holotype male, ventral view. 3, Lateral habitus, female (OSUC 67887). 4, Head and mesosoma, female, dorsolateral view (OSUC 67073). 5, Head, male, frontal view (OSUC 90315). 6, Scutellum and forewing, dorsal view (OSUC 83620). Scale bars in millimeters.

Figs. 7–12. Archaeoscelio filicornis Brues. 7, Holotype male, dorsolateral view. 8, Holotype male, ventrolateral view. 9, Lateral habitus, male (OSUC 67821). 10, Lateral habitus, female (OSUC 67397). 11, Forewing, female, dorsal view (OSUC 67821). 12, Ventrolateral view, female (OSUC 64198). Scale bars in millimeters.

Figs. 25–30. Plaumannion fritzi Masner and Johnson, n.sp. 25, Holotype female, lateral habitus (OSUC 146569). 26, Holotype female, dorsal habitus. 27, Holotype female, head, frontal view. 28, Forewing. 29, Metasoma, paratype female, frontal view (OSUC 146570). 30, Metasoma, paratype female, dorsal view. Scale bars in millimeters.

Figs. 31–34. Plaumannion yepezi García, n.sp., holotype female (OSUC 146571). 31, Mesosoma and metasoma, lateral view. The angulate profile of mesoscutum is an artifact. 32, Mesosoma and metasoma, dorsal view. 33, Head, frontal view. 34, Head, lateral view. Scale bars in millimeters.

Figs. 41–49. Detail of forewing venation; apex of wing to right. 41, Proplatygaster sp. (Platygastridae). 42, Nixonia watshami Johnson and Masner (Scelionidae: Nixoniini). 43, Sceliomorpha sp. (Scelionidae: Sparasionini). 44, Neuroscelio doddi Galloway, Masner, and Austin (Scelionidae: putatively Gryonini). 45, Heptascelio sp. (Scelionidae: Scelionini). 46, Oxyscelio sp. (Scelionidae: Baryconini). 47, Chromoteleia sp. (Scelionidae: Baryconini). 48, Phasgonophora sp. (Chalcidoidea: Chalcididae). 49, Liopteron sp. (Cynipoidea: Liopteridae). m, marginal vein; pm, postmarginal vein; sm, submarginal vein; st, stigmal vein. Scale bars in millimeters.

Figs. 35–40. Huddlestonium exu Polaszek and Johnson, n.sp. 35, Holotype female, lateral habitus (OSUC 148692). 36, Paratype female, dorsal habitus (OSUC 148693). 37, Holotype female, head, frontal view. 38, Antenna, lateral view. 39, Wings. 40, Ovipositor, lateral (top) and ventral view (bottom). gp, gonoplacs. Scale bars in millimeters.

Figs. 13–18. Cobaloscelio cuspidatus Johnson and Masner, n.sp. 13, Holotype male, lateral habitus (OSUC 83643). 14, Holotype male, frontolateral view. 15, Holotype male, metasoma, lateral view. 16, Paratype female, lateral view (OSUC 83621). 17, Female, ventral view (OSUC 83621). 18, Female, dorsal view of scutellum, forewing (OSUC 83621). Scale bars in millimeters.