Eocenobius praestigitator, Alekseev & Bukejs & Háva & Zahradník, 2023

Alekseev, Vitalii, Bukejs, Andris, Háva, Jiří & Zahradník, Petr, 2023, A new genus and species of Ernobiinae (Coleoptera: Ptinidae) from Eocene Baltic amber of the Sambian Peninsula, Baltic Journal of Coleopterology 23 (1), pp. 51-59 : 51-59

Eocenobius praestigitator sp. nov.

( Figs. 1–2 )

Type material. Holotype: No AWI-165 [ CVIA]; adult, sex unknown. Almost complete beetle (right antenna absent) included in a transparent, yellow, flat amber piece of irregular form with dimensions of 21× 13 mm and a maximum thickness of 4 mm; preserved without supplementary fixation. Syninclusions: several detrital particles, two plant trichomes, two legs of an insect (likely Diptera: Tipuloidea).

Type stratum. Baltic amber; Middle–Late Eocene.

Description. Measurements: body length (from anterior margin of pronotum to elytral apex along midline) 2.43 mm, body maximum width across both elytra 1.36 mm; head length 0.57 mm, head maximum width across eyes 0.69 mm; pronotal length 0.43 mm, pronotal maximum width 1.14 mm; elytral length 2.04mm, elytral maximum width 1.36 mm. Body moderately convex; integument dark brown (as preserved); pubescence conspicuous, long, thin, erect.

Head prognathous, mostly hidden in dorsal view, almost as long as wide (including eyes); finely punctate, with distance between punctures 1.0–1.5× diameter of one puncture. Compound eyes protruding, large, finely facetted, hemispherical, weakly impressed near antennal bases. Ommatidial setae absent. Antennae inserted at inner margin of eyes; antennal insertions widely separated, distance between antennal insertions equal to length of antennomeres 1–5. Antennae 11-segmented, with loose, 3- segmented club; antennae moderately long, reaching abdominal ventrite 1 in ventral position. Antennomere 1 subcylindrical, elongate, 2.0× longer than wide; antennomere 2 subovate, slightly dilated apically, 1.5× longer than wide; antennomere 3 elongate, 2.5× longer than wide; antennomeres 4–8subequal in length, elongate, 1.5–1.8× longer than wide; antennomeres 9–10 elongate, slightly flattened, about 3.3× longer than antennomere8; antennomere 11 spindle-shaped, with acute apex, 3.0× longer than wide. Relative length ratios of antennomeres 1–11 equal to 6:4:5:3:3:3:3:3:10: 10:11. Apical maxillary palpomere short, cylindrical, slightly longer than wide, truncated apically. Apical labial palpomere triangular in outline.

Type locality. Yantarny village (formerly Palmnicken), the Kaliningrad Region, W Russia .

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A new genus and species of Ernobiinae ( Coleoptera : Ptinidae ) from Eocene Baltic amber of the Sambian Peninsula

Pronotum slightly narrower than elytra at base, strongly transverse, 2.65× wider than long, with maximum width at base; lateral sides and anterior edge finely margined. Pronotal punctation fine, denser at base, about as large as punctation of head; distance between punctures equal to 1.0–2.0× diameter of one puncture. Pronotal pubescence fine, erect, comparatively short, with setae inconspicuous on disc and longer laterally. Posterior pronotal angles obtuse, rounded; anterior angles rectangular with rounded apices. Anterior pronotal margin rounded, without excision, and not raised; posterior edge bisinuate; lateral sides almost straight, smooth, reflexed.

Scutellar shield small, semicircular, transverse. Elytra short and oval, moderately convex, with maximum width occurring near mid-length, 1.5× longer than wide, 4.74× as long as pronotal length; humeri rounded, distinct. Elytral punctation irregular, fine, with punctures slightly larger than punctation of pronotum and head; distance between punctures equal to 1.5–2.0× diameter of one puncture. Elytral pubescence fine, semierect and shorter on disc, erect and longer laterally. Epipleura narrow extending to abdominal ventrite 1. Metaventrite with disc convex; covered with coarse, rather dense punctation; posterior margin between metacoxae straight, with small triangular notch in middle. Mesocoxaeoval, separated by distance equal to 1.5× their transverse diameter. Metacoxae strongly transverse, separated by distance equal to their length.

All legs are relatively consistent in shape, and finely punctate. Mesocoxaeoval, transverse; metacoxae strongly transverse,

55 grooved for reception of metatibiae. Metatrochanters large, transverse, angulate. Femora elongate-oval, flattened. Tibiae thin, almost straight, nearly as long as femora. Meso- and metatibiae with one apical spur. Tarsal formula 5-5-5. Tarsi withtarsomeres not lobed; tarsomere 1 the longest; tarsomeres 3–5 widened, short, equal in length. Relative length ratios of metatarsomeres 1–5 equal to 10:5:3:3:3. Pretarsal claws strongly curved, thickened at base.

Abdomen with five visible, freely articulat- ed ventrites, covered with rather densepunctation; ventrite 5 rounded apically. Relative length ratios of ventrites 1–5 equal to 12:15:12:10:13 (measured medially).

Note. Procoxal area and prothorax not visible in type specimen due to head position and milky covering of inclusion within surrounding amber.

Etymology. Specific epithet is Latin word praestigitator , used as noun in apposition and meaning “trickster, juggler, deceiver, impostor”.

Figures

Fig. 1. Eocenobius praestigitator sp. nov., holotype, No AWI-165 [CVIA]: A – habitus, dorsal view; B – habitus, ventro-lateral view. Scale bar = 1 mm.

Fig. 2. Eocenobius praestigitator sp. nov., holotype, No AWI-165 [CVIA]: A – habitus, ventral view; B – antenna (reconstruction).