Waidelotus hoffeinsorum gen. et sp. nov. is described from Eocene Baltic amber and assigned to Waidelotinae subfam. nov. within family Pyrochroidae (Coleoptera). The new subfamily differs from the other subfamilies by the following combination of features: penultimate tarsomere of all tarsi deeply bilobed, antepenultimate tarsomere of each pro- and mesothoracic tarsus slightly bilobed, antepenultimate tarsomere of metathoracic tarsi slightly widened apically; pronotum laterally margined in basal half; eyes emarginate; pretarsal claws appendiculate; prosternal intercoxal process incompletely separating prothoracic coxae; pronotum with fine posterior submarginal groove; head without distinct constriction behind eyes; posterior pronotal pits absent; and elytral pubescence homogenous. It is the only authentic species of Pyrochroidae (Coleoptera) from Baltic amber, pending final placement of Palaeopyrochroa crowsoni Abdullah, 1965. Additionally, the available data on stratigraphy of amber-bearing strata on the Sambian peninsula, and the age and location of Eocene amberiferous forests are discussed. A middle Eocene (mostly Bartonian) age is interpreted for the extinct Central European resin-producing forests resulting in the Sambian amber deposits.

The beetle family Ptilodactylidae is recorded for the first time from Rovno amber, Ukraine. Ptilodactyla odnosum Telnov, Perkovsky, Kundrata and Bukejs sp. nov. and a male of P. eocenica Kundrata, Bukejs and Blank, 2021 are described and illustrated using X-ray micro-computed tomography. Our discoveries of two species in Rovno amber together with recently published findings in Baltic amber and Bembridge Marls suggest that ptilodactylids were rather diverse in Eocene Europe. Identification key to Ptilodactylidae described from European Eocene ambers is provided, and relationships of the Baltic and Rovno amber coleopterofaunas are briefly discussed.

Based on two specimens originating from Eocene Rovno and Baltic ambers, Attagenus (Aethriostoma) gedanicissimus sp. nov. is described, illustrated and compared with the related fossil Mesozoic species A. (Aethriostoma) turonianensis Peris et Háva, 2016. The common beetle species for Baltic and Rovno ambers suggests the exceptional temporal and geographical closeness of palaeoecosystems that produced both amber deposits. An updated checklist of Coleoptera known from Rovno amber (57 species belonging to 20 families) is compiled and provided with a bibliography of the original descriptions. The registered Rovno amber beetle assemblage contains only eight species that also occur in Baltic amber (14 %), while the similarity at the generic level is 56 % at the moment. The relationship between the Rovno and Baltic amber deposits and subjectiveness of present-day results of the beetle assemblage research are briefly discussed (urn:lsid:zoobank.org:pub:289B5A43-C57A-4B75-8A15-6E61F4AFCD81).

Based on six relatively well-preserved specimens from Eocene Baltic amber, Crepidodera tertiotertiaria sp. nov. is described. The new species is illustrated and compared with morphologically similar extant and fossil relatives. It is the third described fossil species of Crepidodera Chevrolat. In addition to the new taxon, new fossil records of C. decolorata Nadein & Perkovsky from Baltic and Bitterfeld amber are presented. A key to species of Crepidodera described from fossil resins is provided, and a checklist of Coleoptera described from Bitterfeld amber is compiled.

Acritus sutirca sp. nov. is described and illustrated from Eocene Baltic amber on the basis of one adult male specimen. As the first extinct member of the subfamily Abraeinae (Histeridae) and the smallest known fossil histerid specimen, this material was examined using a combination of light microscopy and X-ray micro-computed tomography (µCT). Internal features of the abdomen are well preserved, allowing us to study sclerotized parts of the aedeagus and illustrate these structures in detail. The current finding expands the range of known Histeridae diversity from the Eocene (48–34 Ma) “amber forests” of Europe. The absolute size limits and the probable average size for Baltic amber coleopteran inclusions are also briefly discussed (urn:lsid:zoobank.org:pub:A2B17479-8628-47C7-A8D4-3E0789BF088B).

A study of Baltic amber revealed a new fossil species of the genus Bacanius LeConte, 1853. Bacanius gorskii sp. nov. differs from the congener described previously from Eocene Rovno amber, B. kirejtshuki Sokolov and Perkovsky, in the shape of meso-metaventral suture, incomplete subhumeral stria, and the impunctate prosternal lobe (urn:lsid:zoobank.org:pub:EE9C6859-607A-4134-9037-8385601CF42F).