Tettagalma striata Menon

Menon, Federica, 2005, New record of Tettigarctidae (Insecta, Hemiptera, Cicadoidea) from the Lower Cretaceous of Brazil, Zootaxa 1087, pp. 53-58 : 54-56

Tettagalma striata Menon , new species

Figs 1–2

Diagnosis. As for genus.

Description. Adult in ventral aspect, with right forewing almost complete and left forewing largely missing; hind wings not preserved ( Fig. 1 ).

Body. Head and thorax partly obscured by thin film of sediment. Head small, 1 mm long, 3 mm wide, bearing small, lateral eyes; antennae short, inserted before the eyes. Rostrum and most of cuticle not preserved. Thorax 8 mm long, 9 mm wide; legs not preserved. Abdomen 14 mm long robust, elongated, pointed posteriorly; abdomen composed of nine visible segments of slightly different size ( Fig. 1 ): second segment 1 mm long, 9 mm wide; last segment 1.5 mm long, 2.5 mm wide.

Forewings. 25 mm long, elongated, with rounded apex, highly sclerotized, covered by thin layer of sediment, at least over basal area. Costal margin prominent, indented at nodus and thinning toward apex. Costal space slightly wider basally. Nodus situated 12 mm from wing base. Sc+R origin at wing base, straight, prominent, bifurcating at approximately a quarter of wing length (6 mm from wing base); R simple, almost parallel to costal margin, with slight indentation at nodal line, reaching the margin anteriorly to apex. Rs with three branches, basally straight, slightly sigmoidal distally, first two branches reaching margin anterior to apex ( Fig. 2 ). Crossvein rs­ma straight, simple, situated on distal half of wing, with anterior tip tilted toward wing base. M+CuA origin apparently from R, near wing base, straight, bifurcating at intersection with cross vein scp+r­m+cua; the latter long, vertical, strongly prominent; M branches, MA and MP, originating before nodal line; MA forking well after nodal line; MA slightly indented at level of ma­mp1 crossvein; MP slightly sigmoid, with two apical branches. CuA simple, initially straight, curving anteriorly near nodal line, deflected abruptly along nodal line and curving posterorly to margin. Crossveins mp­cua long, prominent, distally placed. CuP apparently straight and anal area not visible, obscured by body. Cross venation between the main longitudinal veins forming eight closed apical cells and four closed ante­apical cells ( Fig. 2 ). Marginal membrane relatively wide, 0.40. 6 mm, bearing prominent striation. Striae equidistant, approximately 0.2 mm. Hairs and setae have left an impression basally on wing costal area. Original colour pattern across radial, medial, and cubital systems preserved as a dark brown coloration.

Holotype. SMNS 65507, deposited in the Staatlisches Museum für Naturkunde Stuttgart, Germany.

Etymology. From the Latin striata , in reference to the parallel striae in the marginal membrane.

Remarks. This genus and species is most similar to the extant Tettigarcta and to Liassotectigarcta from the Liassic of Germany. It differs from the Recent genus by having more branches of MA, the fork of M being placed more distally, closer to nodal line, and by the basal venation with the origin of M closer to the base. The most noticeable difference from Liassotectigarcta is the wing length (42.7 mm in Liassotettigarcta). Furthermore, the new species differs also from this species mainly by the forewings being wider with rounded apex, and by having a wider marginal membrane. CuA in Liassotettigarcta is not deflected anteriorly at the nodal line as in Tettagalma; this may be caused by the nodal line being more distally placed in Liassotettigarcta.

Figures

FIGURE 1. Tettagalma striata Menon, new genus and species; photograph of the holotype SMNS 65507. Scale bar represents 10 mm.

FIGURE 2. Tettagalma striata Menon, new genus and species; in line drawing of the holotype SMNS 65507. Scale bar represents 5 mm.