Alicodoxa rasnitsyni, Emeljanov, Alexander F. & Shcherbakov, Dmitry E., 2011

Emeljanov, Alexander F. & Shcherbakov, Dmitry E., 2011, A new genus and species of Dictyopharidae (Homoptera) from Rovno and Baltic amber based on nymphs, ZooKeys 130, pp. 175-184 : 177-179

Alicodoxa rasnitsyni sp. n. Figs 15

Material.

Holotype, 4th instar nymph, SIZK K-3719, Klesov, Rovno amber, Ukraine; Late Eocene. Syninclusions: Mycetophilidae , Sciaroidea , Symphypleona, Acari, stellate hairs. Petaloid blind fissures arising all around lateral margins of the nymph and directed nearly laterad completely separate its dorsal and ventral sides so that only parts of its mid and hind legs are visible from above. The ventral aspect is mostly masked with variously directed fissures and in some places with milky impurities.

Description.

Nymph dark brown, ovoid, moderately elongate, 4.1 mm long, 2.2 mm wide; head projecting forwards beyond oval contour; dorsum finely transversely shagreened. Coryphe somewhat longer than wide; its lateral and anterior margins forming regular parabola; its posterior margin very shallowly concave, situated at about eye midlength in dorsal aspect. All carinae of coryphe, including posterior one and medial one, well developed. Metope (only partly visible) with medial areas somewhat widened at head apex; lateral areas with two rows of sensory pits, with an additional row of four smaller pits in between the two rows. Rostrum reaching beyond hind coxae, apical segment shorter than subapical one.

Pronotal disc strongly projecting forwards (2/3 of its median length situated anterior to level of posterior eye margins), its anterior margin truncate, almost straight, anterolateral angles rounded, lateral margins moderately diverging backwards. Posterior margin of pronotum with deep right-angled emargination reaching almost 1/3 of pronotal disc length. Pronotal disc slightly narrower and 1/4 shorter along midline than coryphe, bordered with distinct carinae along all free margins, medial carina also distinct, but posterolateral carinae undeveloped, and boundary between disc and lateral lobes traceable only as flexure of surface plane (posterior ends of these flexures close to points where lateral carinae of mesonotal disc approach pronotal margin). Sensory pits of pronotal disc and paradiscal areas forming one entity: disc with row of 4 large pits along lateral margin and 3 smaller pits in second, more medial row; paradiscal area with 6 large pits in marginal row (indistinctly subdivided into two groups, each with 3 pits) and 8-10 smaller pits in second row. Humeral area with 3 pits in main row and 1 additional pit; pectoral group of pits (about 7 in two tangled rows) situated as is usual in the family near posterior margin of paranotal lobe. Lateral and collateral carinae distinct. Mesonotal disc arrow-shaped anteriorly (its lateral carinae anteriorly converging at nearly acute angle, running parallel to posterior pronotal margin). Group of 6-7 pits (3 medial pits larger) situated laterad of lateral carinae. Fore wing pads mediad of subcostal carina with 3 pits (in triangle) in middle part and 1 pit near apex, and in costal area with 2 pits in middle part (against group of 3 pits). Posterior margins of fore and hind wing pads subparallel, directed obliquely posterolaterad. Metanotal disc rectangular, about 1.3 times as wide as long, with all carinae distinct. Medial group of pits laterad of disc similar to that on mesonotum; hind wing pad subapically with 2 pits in oblique row subparallel to posterior pad margin. Fore legs slightly widened, as long as mid legs. Fore femora without subapical tooth on posteroventral carina. Fore tibiae slightly flattened, lanceolate, widest about midlength. Mid tibiae not widened, relatively slender. Hind tibiae with 5 lateral spines including knee spine; apical teeth not possible to count. Hind tarsus three-segmented.

Abdomen with well developed middorsal carina, indistinct intermediate carinae on tergites IV–V, without sublateral carinae. Tergites I–III without pits; tergites IV–V with long (complete) rows of 8-10 pits, 5th or 6th pit (from body midline) displaced anteriad (sometimes there are 2 such pits, forming rudimentary second row anteriorly - see Fig. 1). Lateral areas of tergites IV–V with 3-4 pits in row or group. Tergites VI–VIII with several pits displaced medially (2 pits on VI, 2 pits on VII, 0-1 pit on VIII - absent at one side) and several pits laterally (ventrally: 3 pits on VI, 2 pits on VII, 1 pit on VIII). Lateral area with 3 pits on tergite VI, 2 pits on tergite VII, and 1 pit on tergite VIII. Tergite IX ventrally with pair of pits (1 pit at each side).

Wax plates situated in subtriangular posterolateral areas of tergites VI–VIII, separated from rest of tergite by carina and facing posteriad. Wax plates of uniform structure: large rounded lower (lateral) plate with discernible circular wax gland pores and small adjacent upper (medial) plate. Small upper wax plate on tergite VII subdivided, crossed by narrow chitinous bridge nearly perpendicular to body sagittal plane.

Remarks.

The three-segmented hind tarsus in the holotype of Alicodoxa rasnitsyni sp. n. indicates the 4th or 5th instar, while the fore wing pads not nearly reaching the apices of hind wing pads suggest the 4th instar (or 5th instar of a brachypterous planthopper, but the latter is not consistent with the presence of well developed abdominal wax plates).

In the nymphs of Dictyopharinae posterolateral carinae of the pronotal disc are usually absent, as in the new genus, and sensory pits of the second row are arranged more or less evenly across the imaginary boundary between pronotal disc and paradiscal area, though their number is not the same at the left and right sides.

The 3rd instar nymph from Baltic amber illustrated by Weitschat and Wichard (1998: pl. 46a) agrees with the holotype of Alicodoxa rasnitsyni sp. n. in all diagnostic characters. The original drawing of the 3rd instar nymph of " Pseudophana reticulata" ( Germar and Berendt 1856: pl. II, fig. 4a) is inaccurate, e.g. the legs are shown too short and the sensory pits on the fore wing pad too numerous. Nevertheless, several salient features allow recognizing it as conspecific with the holotype of the new species. Therefore, Alicodoxa rasnitsyni sp. n. is recorded from both Baltic and Rovno amber.