Danae sembanata, Alekseev & Tomaszewska, 2025

Danae sembanata sp. nov.

( Figs 1–8 View FIGURES 1–2 View FIGURES 3–5 View FIGURES 6–8 )

Material examined. Holotype: No KAM 5726/6 [KRAM]; “* Holotype / Danae sembanata / sp. nov. / Alekseev et Tomaszewska / des. 2025” [red handwritten label]; adult, sex unknown (probably female). Almost complete beetle (right fore and middle leg are missing) included in a small, transparent, yellow amber piece with dimensions of 17 × 13 × 6 mm and weight about 1.2 g; preserved without supplementary fixation. The specimen is covered with white opaque cloud on ventral surfaces of body and appendages, so-called ‘Verlumung’ i.e. nontransparent, milky coloured amber with a high density of microscopic vesicles, caused by gas or liquid emulsion in non-hardened resin before polymerisation. Syninclusions: one specimen of Nematocera (Diptera), two specimens of Symphypleona (Collembola), one specimen of Acari (Arachnida) nymph, and several fagacean trichomes.

Type locality. Southeastern Baltic Sea coast ( Kaliningrad Region) .

Type horizon. Baltic amber, most probable from the Eocene amber-bearing layers of Blaue Erde (Blue Earth) within the Prussian Formation; estimated age: middle-late Eocene.

Description. Measurements: total body length 3.37 mm, body maximum width 1.71 mm; pronotum length 0.79 mm, pronotum maximum width 1.36 mm; elytra length 2.29 mm, elytra maximum combined width 1.71 mm; head length 0.29 mm, head width (including eyes) 0.71 mm; antenna length 1.57 mm. Body shape elongate oval in dorsal outline, convex dorsally; integument uniformly dark brown (as preserved); dorsum covered with appressed dense setation.

Head prognathous, not retracted into prothorax, slightly declined; sparsely covered with fine punctation, distance between punctures distinctly larger than diameter of one puncture. Vertex evenly convex. Compound eyes oval, vertical diameter 1.5× as horizontal diameter, prominent, entire, coarsely facetted, without interfacetal setae. Fronto-clypeal suture present, almost straight. Clypeus transverse, with widely arcuate anterior margin. Antennae composed of 11 antennomeres, clubbed, extending at least to elytral base, covered with appressed fine setation; scape and pedicel cylindrical, elongate, about 2.0× as long as wide; antennomeres 3–8 at least weakly elongate, slightly dilated apically, subequal in shape and size, about 1.8–2.0× as long as wide; antennomeres 9–11 enlarged, forming distinct loose antennal club; antennomeres 9 and 10 weakly flattened, distinctly dilated apically, about 1.5× as long as wide; antennomere 11 symmetrical, largest, ovoid, with appressed fine setae and longer sparse erect hairs, with rounded apex, about 1.5× as long as wide. Maxillary palpi 4-segmented, palpomere 4 elongate, conical, with truncate apex, about as long as palpomeres 1–3 combined.

Pronotum transverse, 1.7× as wide as long, widest in anterior one-third, slightly narrowed posteriad. Pronotal disc weakly convex, with lateral margins as wide as antennomere 3 and weakly raised, with paired arcuate longitudinal lateral sulci extending almost to pronotal mid-length and distinct transverse basal sulcus. Pronotal punctation coarse and dense, distance between punctures distinctly smaller than diameter of one puncture. Pronotal pubescence fine, appressed. Posterior pronotal margin weakly bisinuate; lateral pronotal edges smooth, not crenulate, widely rounded in anterior portion and almost straight in posterior portion, widely bordered; anterior pronotal margin deeply emarginate. Posterior pronotal angles triangular, weakly acute; anterior angles widely rounded, weakly projecting anteriad.

Scutellar shield rounded, strongly transverse, 2.0× wider than long, covered with fine punctation. Elytra elongate, 1.3× as long as wide, convex, completely covering abdomen, widest before middle; with base slightly wider than pronotal posterior margin; lateral sides gently rounded; 2.9× as long as pronotal length; with weak humeral calli; densely covered with short, fine, inconspicuous setation. Elytral punctation irregular, coarse and dense (as pronotal punctation), laterally rugose; distance between punctures distinctly smaller than diameter of one puncture. Sutural stria indistinct in anterior one-third of elytral length, very fine and barely visible in posterior twothirds. Mesometaventral junction arcuate. Metaventrite with convex disc, transverse; discrimen not apparent.

Legs rather short, finely punctate and pubescent. Mesocoxae hemispherical, separated by mesoventral process distinctly narrower than mesocoxal cavity diameter; metacoxae transverse, widely separated by trapezoidal process of abdominal ventrite 1. Trochantero-femoral join oblique. Femora subclavate. Tibiae thin, weakly widened apically, simple (without angulations or projections), with very short apical spines; pro- and mesotibiae straight, metatibiae weakly curved. Tarsi short, about 0.4× as long as tibiae length; tarsal formula 4-4-4; tarsi pseudotrimerous; tarsomere 1 ventrally pubescent, with narrow elongate triangular lobe; tarsomere 2 about as long as tarsomere 1, ventrally pubescent, with wide triangular lobe; tarsomere 3 very small, hidden in a lobe of tarsomere 2, as long as wide; tarsomere 4 longest, cylindrical, curved. Tarsal claws curved, narrow, simple.

Abdomen with seemingly six ventrites, slightly convex. Abdominal ventrite 1 longest. Relative length ratios of ventrites 1–6 (medially):?3-?1.5-?1-?1-?1-?1.

Differential diagnosis. The new species, Danae sembanata sp. nov., can be distinguished from the other representatives of the genus based upon the following combination of characters: dense and coarse punctation on elytral disc whereas elytral sides are rugosely punctate, antennomeres 9-11 distinctly elongate, subequal in length, with rather narrow antennomere 11, and well developed and comparatively long lateral sulci on the pronotum. Moreover, from the most similar, ‘putatively’ closest Danae testacea (Ziegler) , the new species differs by having less elongate, more oval body, the hind angles of the pronotum weakly acute (vs strongly acute in D. testacea ), sutural stria on each elytron present along at least 2/3 of elytral length (present at most along 1/3 of elytral length in D. testacea ), and antennomeres 9–11 distinctly elongate and subequal in length (vs antennomeres 9 and 10 shorter than terminal antennomere, and more transverse in D. testacea ; additionally, despite a lack of strong dimorphism displayed in antennal club in D. testacea , antennomere 9 in male is weakly larger (longer and wider) than antennomere 10).

Etymology. The specific epithet sembanata is toponymic, a compound adjective derived from Semba (also Sambia or Samland, the historical area in the west part of the present-day Kaliningrad Region) and the Latin natus, -a, -um (born).

Note on the presumed palaeoecology of the fossil. The ecology of modern species of Danae has not been studied in detail. The widely distributed in the eastern US, the northernmost species of the genus, Danae testacea , occurs largely as a relict species in old-growth hardwoods and is associated with subcortical fungi in hardwoods and softer species of Polyporaceae ( Majka 2007) . For the fossil species, a similar biology, i.e. a mycophagous diet and dendrophilous mode of life in lower layer of the forest, can be assumed.