Micropresbyteria Liu and Engel, 2007

LIU, ZHIWEI, ENGEL, MICHAEL S. & GRIMALDI, DAVID A., 2007, Phylogeny and Geological History of the Cynipoid Wasps (Hymenoptera: Cynipoidea), American Museum Novitates 3583, pp. 1-48 : 14-17

Micropresbyteria Liu and Engel , new genus

TYPE SPECIES: Micropresbyteria caputipressa Liu and Engel , new species.

DIAGNOSIS: F1 of male antenna medially not flattened and not twisted. Head distinctly compressed longitudinally and not impressed posteriorly; lateral occipital carina laterally strongly expanded into a broad lobular structure; lower face glabrate, with a simple, more or less complete median carina. Anterior pronotal flange short; anterior submedian depression open laterally; dorsal pronotal area narrow but distinct; lateral pronotal carina present; lateral pronotal surface without foveate sculpture. Mesoscutum glabrous; median longitudinal impression and lateral notauli distinct; mesoscutellum posteriorly extended into a prominent horizontal process; lower mesopleuron ventrally strongly expanded into a broad lobular structure, posteriorly covering basal part of mesocoxa. Forewing with bulla present in Sc+R 1; Rs+M issuing from close to posterior end of first free abscissa of M (5 basal vein). Mesocoxa inserted almost vertically; metacoxa distinctly dorsomedially swollen and dorsolaterally distinctly depressed. Petiolar annulus low and without longitudinal carina; petiole slightly shorter than wide, with distinct longitudinal carinae.

ETYMOLOGY: The specific epithet is derived from the Greek words mikros (meaning ‘‘little’’ or ‘‘small’’) and presbytrion (meaning ‘‘an assemblage of elders’’). The name is feminine.

COMMENTS: The extensive lobular expansion of the upper part of the lateral occipital carina and massively expanded ventrolateral carina of the mesopectus separate Micropresbyteria from all other cynipoids. The longitudinally distinctly compressed head, the lack of distinct sculpture on the head and mesosoma, the short anterior pronotal flange, and the downward insertion of the meso- and metacoxae strongly indicate that the fossil belongs to the microcynipoids. The presence of an obvious dorsal pronotal area, the position of the proximal end of Rs+M close to the posterior end of the first free abscissa of M (5 basal vein), and the presence of the longitudinal carina dorsolaterally on the metatibia further suggest that the genus belongs to the family Figitidae . Because of a lack of information for female characters, which are more crucial in cynipoid phylogeny, we only provisionally place the genus in Figitidae .

Micropresbyteria caputipressa Liu and Engel , new species figures 9 , 10

DIAGNOSIS: As for the genus (see above).

DESCRIPTION: Male. Body length 1.00 mm; forewing length 0.90 mm. Body mostly black to dark brown; wings hyaline, without any macula or band. Antenna cylindrical, 14- segmented; pedicel almost spherical, one-half as long as scape; F1 medially not flattened and not twisted as in male of most known species of cynipoids, slightly longer than F2 (F2 seven-sixths length of F1) and much thicker than the latter; elongate placodeal sensilla present on all flagellomeres. Head compressed longitudinally, attached high to mesosoma; frons, vertex, gena, and malar space glabrous; compound eye prominent, distinctly produced in front of gena, and vertically much extended; malar space reduced to narrow strip beneath compound eye; gena not expanded behind compound eye. Lateral surface of pronotum glabrous. Mesoscutum curved dorsally in lateral view and glabrous, with sparse pubescence; without transverse costa; median impression and lateral notauli distinct; mesoscutellum flat dorsally and posteriorly projected into a blunt process (an artifact of preservation?); mesopleuron glabrous; lower mesopleuron ventrally expanded; mesosoma across mesopleuron almost as high as long, excluding mesoscutellar process. Mesocoxa inserted almost vertically, not obliquely at posterior area. Propodeum devoid of processes; nucha short and broad in lateral view. Wings entirely hyaline, with sparse pubescence; all wing margins ciliate. Forewing with marginal cell closed, about 2.6 times as long as wide; bulla in Sc+R 1 present, 2r-rs oblique, sloping outward posteriorly; areolet large; Rs+M nebulous, arising from posterior end of first free abscissa of M (5 basal vein). Anterior margin of hind wing with three hamuli. Metabasitarsus shorter than combined lengths of second to fifth metatarsomeres; metacoxa dorsally distinctly depressed; metatibia dorsolaterally with a distinct longitudinal carina; all pretarsal claws simple, without basal lobe. Petiolar annulus relatively long, attached low to propodeum; segmentation of metasoma indistinct owing to imperfect preservation. Female. Unknown.

HOLOTYPE: Male , RTMP 96.9.170, Late Cretaceous (Campanian), Grassy Lake (110 ° 40 9 W, 49 ° 45 9 N), Alberta, Canada; deposited in RTMP.

ETYMOLOGY: The specific epithet is derived from Latin caputa (meaning ‘‘head’’) and pressus (meaning ‘‘pressed’’). The name refers to the longitudinally compressed head.

SUBFAMILY EUCOILINAE THOMSON

DIAGNOSIS: The subfamily is easily distinguished from all other cynipoids by the presence of a mesoscutellar cup or plate with a deep depression centrally or posteriorly. In addition, eucoiline females, except for two of the new fossil genera described below, have the second through fourth metasomal terga (5 abdominal T3–5) fused, a feature shared only with the Pycnostigminae (Figitidae) among cynipoids.

COMMENTS: The presence of the mesoscutellar plate undoubtedly supports the monophyly of the subfamily, a feature exhibited by all three of the taxa treated herein. The new genera Anteucoila and Jerseucoila (see below), however, lack the fusion of metasomal T2–4 and are therefore obviously basal to all other eucoilines, representing a stem group to the subfamily as it is understood based on modern taxa. However, as already noted, Anteucoila and Jerseucoila possess a well-developed mesoscutellar cup, indicative of their placement as eucoilines. The third genus, Syneucoila , is a typical crown-group eucoiline and is, in fact, apparently related to the clade consisting of the Zaeucoila generic group and the core + higher eucoilines ( Fontal-Cazalla et al., 2002; see below).

The Eucoilinae is the most species-rich figitid subfamily, currently with about 80 genera and 1000 species. Where known, eucoilines are restricted to hosts of the cyclorrhaphan Diptera (Ronquist, 1999, and references therein). The other Cretaceous genus, Syneucoila (see below), is more typical of modern Eucoilinae (yet still rather plesiomorphic for its clade), attesting to the antiquity of the lineage.

Figures

Fig. 9. Photomicrograph of holotype male of Micropresbyteria caputipressa Liu and Engel, new genus and species (RTMP-96-9-170).

Fig. 10. Holotype male of Micropresbyteria caputipressa Liu and Engel, new genus and species (RTMP-