Nosodendron ( Dendrodipnis ) andrushchenkoi, Alekseev & Bukejs, 2025

Nosodendron ( Dendrodipnis) andrushchenkoi sp. nov.

( Figs 1–6 View FIGURES 1–2 View FIGURES 3–4 View FIGURES 5–8 )

Type material. Holotype: No. KAM 9302 [KRAM]; “* Holotype / Nosodendron / ( Dendrodipnis ) / andrushchenkoi sp. nov. / Alekseev et Bukejs des. 2025” [red handwritten label]; adult, sex unknown. The specimen is a complete beetle included in a transparent yellow amber piece, which measures 18× 9 mm with a maximum thickness of 3 mm and is preserved without supplementary fixation. Syninclusions: one stellate Fagaceae trichome attached to right humerus of the inclusion, several minute detrital particles, one mite specimen attached to the right posterior part of the beetle metasternum.

Type locality. Yantarny settlement (formerly Palmnicken), Sambian (Samland) Peninsula, Kaliningrad Oblast (region), Russia .

Type horizon. Baltic amber, middle-late Eocene.

Description. Measurements: body length (from anterior margin of clypeus to elytral apex along midline) 3.25 mm, body maximum width (across elytra) 2.38 mm; pronotum length 0.65 mm, pronotum maximum width 1.8 mm; elytra length 2.25 mm, elytra maximum width 2.38 mm. Body widely oval, strongly convex dorsally, flattened ventrally ( Figs 1–3 View FIGURES 1–2 View FIGURES 3–4 ); integument unicolorous black (as preserved); dorsum finely punctate, glabrous, without setation.

Head prognathous, partially inserted into prothorax, broadest at eyes, densely and finely punctate, punctures separated by 1.0–1.2× puncture diameter. Frontoclypeal suture absent; anterior edge of clypeus semicircular; frons wide, weakly convex. Compound eyes small, gently prominent, visible from above, finely facetted, without interfacetal setation. Mentum subparallel-sided, weakly transverse; without median concavity, sulcus or impression; covered with fine punctation, distance between punctures slightly larger than puncture diameter. Antennal insertions concealed from above. Antenna 11-segmented, with loose 3-segmented club and antennomere 3 longest ( Fig. 6 View FIGURES 5–8 ). Antennomere 1 rounded, about as long as wide; antennomeres 2 and 4–8 subcylindrical, slightly dilated apically, weakly elongate; antennomere 3 cylindrical, distinctly elongate, about 3.0× as long as wide and 1.7× as long as antennomeres 1–2 combined; antennomeres 9–11 transverse; relative length ratios of antennomeres 1–11 equal to 10:10:35:10:13:10:10:10:13:10:6.

Pronotum widest at base, narrowed anteriad, broadly transverse, about 2.8× as wide as long, with weakly convex disc, densely covered with fine irregular punctures separated by 1.0–2.0× puncture diameter, interspaces between punctures shiny, glabrous. Anterior pronotal margin emarginate, posterior margin and lateral sides widely arcuate, smooth. Anterior pronotal angles protruding, triangular, pointed; posterior angles obtuse, broadly rounded. Prosternum in front of coxae shorter than half length of prosternal process; lateral portions of prosternum completely separated from medial portion and distinctly lowered for reception of protrochanters and femora. Prosternal process long, tapering posteriad, narrowly rounded apically, extending to mesoventrite. Hypomeron excavated for reception of antennae and prothoracic legs. Procoxal cavities transverse, broadly open posteriorly, separated by about 0.5× of their maximum diameter.

Scutellar shield equilaterally triangular, finely punctate.

Elytra widely oval, widest near middle, microsculptured by fine rounded cells (discernible at elytral base) and punctate by two types of punctures, large and small ( Fig. 5 View FIGURES 5–8 ). Large punctures form 11 almost regular rows in elytron; each row consisting of 15–18 punctures separated by distance 3.0–4.0× as wide as diameter of one puncture; distance between rows 4.0–5.0× as wide as one puncture diameter; large punctation discernible in anterior seveneighths of elytral length, erased apically. Small elytral punctation fine; with diameter about 0.2× as large as diameter of one large puncture; arranged in short irregular and wriggling rows consisting of 10 and less punctures; as large as punctation on head and pronotum and about as large as rounded cells of elytral microsculpture. Elytra surface lacking tufts and separate scale-like setae. Epipleura wide, broadest basally, reaching to abdominal ventrite 4.

Mesothorax ( Fig. 4 View FIGURES 3–4 ) short, as long as diameter of mesocoxae, with deep and wide notch anteromedially for reception of prosternal process. Mesocoxae transverse, widely separated by distance corresponding about to 1.5× their maximum width. Thorax anterolaterally of the mesocoxae depressed for reception of mesothoracic legs. Metaventrite wide, with weakly convex disc; covered with small punctures; punctation sparse and fine in median part, separated by 3.0–4.0× puncture diameter; punctation enlarged and condensed posteriolaterally, being separated by 0.5× diameter of one puncture in posterior part of metaventrite. Metacoxae transverse, narrowly separated by narrowly rounded anterior process of abdominal ventrite 1.

Legs short and rather flat. Trochanters subtriangular. Femora simple, about as long as tibiae, punctate, flattened, broadest medially and narrowed apically, with groove on inner margin for the reception of tibiae. Metacoxal plates developed, knife-shaped, punctate. Tibiae elongate, almost straight, slightly widened apically; meso- and metatibiae with recumbent setae and denticles along outer edges. Protibia with broad semicircular preapical emargination on outer edge for reception of protarsus. Tarsi slender, about 0.55× as long as tibiae; tarsal formula 5-5-5; tarsomeres 1–4 simple, equal in length; apical tarsomere longest. Claws simple, 0.4× as long as apical tarsomere, equal in size and shape.

Abdomen with five ventrites; ventrites 1–4 with elongate lateral depressions for reception of metathoracic legs ( Fig. 2 View FIGURES 1–2 ). Punctation of ventrites denser medially and sparse in impressed parts. Short longitudinal sulci in anterior margins of ventrites absent. Ventrite 1 with narrowly rounded intercoxal process; ventrite 5 with widely rounded posterior margin; relative length ratios of abdominal ventrites 1–5 equal to 5:2:2:2:3 (measured medially).

Differential diagnosis. The new extinct species, Nosodendron andrushchenkoi sp. nov., differs from extant congeners by the following combination of characters: (1) antennomere 3 clearly longer than antennomeres 1–2 combined, pronotum and elytra without distinct setal patches, mentum subparallel-sided (subgeneric characters for placement within Dendrodipnis ); (2) mentum lacking sulcus or impression (a character corresponding to the Asian ‘ Nosodendron ( Dendrodipnis) species group 3’ sensu Yoshitomi (2023) and also present in some Neotropical species, e.g., those of the ‘ angelum group’); (3) elytra with rows of large punctures, as well with rather irregular fine punctation and cell-like microsculpture; (4) dorsal and ventral body setation completely absent (fine punctures of dorsum and venter often bear suberect bristles or recumbent setae in many extant species); (5) abdominal ventrites simples, without longitudinal sulci in anterior margins; and (6) comparatively small body size ( 3.25 mm in the single known specimen).

Etymology. The species is named in honor of Mr. Konstantin V.Andrushchenko ( Kaliningrad), a great enthusiast in collecting Baltic amber insect inclusions, who generously donated the type specimen from his private collection to KRAM.