Megalyra truncata, Perrichot, 2009

Fuente, Ricardo Pérez-De La, Perrichot, Vincent, Ortega-Blanco, Jaime, Delclòs, Xavier & Engel, Michael S., 2012, Description of the male of Megalava truncata Perrichot (Hymenoptera: Megalyridae) in Early Cretaceous amber from El Soplao (Spain), Zootaxa 3274, pp. 29-35 : 30-33

Megalava truncata Perrichot, 2009

( Figs 1−2 )

Material. Male, CES 391.2, from Early Cretaceous (Albian) El Soplao amber (Cantabria, Spain). The specimen is almost complete, missing only the distal parts of some legs. Its preservation is generally good but the head and the anterior part of mesosoma are surrounded by cracks, rendering it difficult to observe the longitudinal median sulcus of vertex, the clypeus shape, and mandibular teeth. In addition, the piece of amber also contains abundant syninclusions: two coiled charcoalified plant fibers ( Fig. 1 A; see Najarro et al. 2010: fig. 7.1) in contact with the right antenna of the megalyrid, a new genus and species of snakefly (Pérez-de la Fuente et al. in prep.), two coleopterans, another hymenopteran, one immature aphid, a cluster of trichomes, and some other indeterminate organic remains. The syninclusions prevent polishing from either side of the preparation and limit the dorsal observation of the megalyrid, so the hind wing venation is not discernible and measurements of the width of the body are not possible.

Description. Head. Shorter than wide and shorter than high, likely broader than mesosoma. Compound eyes higher than long, not pubescent; postorbital margin without groove, foveae, or carina. Relative distance between lateral ocelli not visible, lateral ocelli almost aligned with the posterior margin of compound eyes. Occipital carina foveate. Antenna elongate; toruli closer to each other than to compound eyes; pedicel half as long as scape, scarcely longer than broad; flagellomeres cylindrical; FIX–XII shortest, scarcely twice as long as thick; FI, FV–VIII about three times as long as thick; FII–IV longest, about four times as long thick. Right mandible as visible with one small basal tooth and two larger apical teeth; left mandible with one large apical tooth visible.

Mesosoma ( Fig. 1 B). Anteromedial part of pronotum only slightly visible dorsally; presence of notch on hind lateral margin of pronotum not clear. Mesoscutum abruptly truncate anteriorly, with strong anterolateral carina, and with posterior margin not straight dorsally; median mesoscutal sulcus distinct, not crenulate; parapsidal lines well impressed, widely separated from median mesoscutal sulcus and running nearly parallel to it. Axillae large, slightly meeting at medial angles anteriorly, with scutoscutellar sulcus broadly crenulate. Mesoscutellum acute posteriorly, without a transversal sulcus. Mesometapectal sulcus (sensu Vilhemsen et al. 2010b) foveolate. Posterior margin of metapleuron foveolate. Propodeum with sharp angle between dorsum and almost vertical posterior surface.

Wings ( Fig. 2 B). Membrane hyaline, with microtrichia. Forewing exceeding posteriorly the tip of the metasoma; pterostigma relatively elongate (slightly longer than medial cell); vein R1 long, almost reaching wing apex; Rs present between r-rs and Rs+M forming a large submarginal cell, apical segment of Rs straight and tubular, reaching wing margin; M+Cu tubular, aligned with Rs+M; marginal and submarginal cells closed by tubular veins, marginal cell narrow and elongate; medial cell subrectangular, very small, entirely closed by tubular veins, with 1m-cu very short and slightly oblique; distal parts of M and Cu tubular, almost reaching wing margin.

Legs. Foreleg with preening brush of stiff, short setae visible on inner margin of tarsomeres; hind leg stout, with large coxa; metafemur swollen, without comb-like spines along inner margin; metatibia with two short apical spurs, without comb-like spines along inner margin; pretarsal claws small, simple, with an almost equally sized arolium.

Metasoma. Ovoid, not especially elongate (less than half the body length). Tip of genitalia with tergite 9/10 visible, bearing two well-developed spatulate structures interpreted as cerci and some long and very fine setae; volsellae visible, bearing a few minute, short setae; parameres straight, poorly developed, ending at same level as T9/ 10 ( Fig. 2 C).

Measurements (in mm). Body length 2.30; head length 0.35, height 0.67; antenna length 1.88; mesosoma length 0.80; forewing length 1.65; metasoma length 1.02.

Figures

FIGURE 1. Photomicrographs of Megalava truncata Perrichot, 2009, new specimen CES 391.2 from El Soplao amber, male. A, lateral habitus; B, detail of mesosoma. Scale bars: A = 1 mm, B = 0.5 mm.

FIGURE 2. Line drawings of Megalava truncata Perrichot, 2009, new specimen CES 391.2 from El Soplao amber, male. A, camera lucida drawing, lateral habitus; B, diagrammatic illustration of forewing reconstruction; wing width has been estimated; C, camera lucida drawing of the genitalia in lateral view. Scale bars: A, B = 1 mm, C = 0.1 mm.