The present Catalogue includes all available names, both valid and invalid (synonyms of family group names excepted), of extant beetle taxa described before 1st January 2023 and known to occur in the Palaearctic Region as defined in the Catalogue (see chapter Distribution Information). Taxa described in 2023 are included as far as we were aware of them. Unjustified emendations and names rejected by the Commission are also included, with appropriate indications. Fossil taxa, misspellings, misidentifications and nomina nuda are not included in the body of the Catalogue.

The higher classification follows the Handbook of Zoology (Leschen & Beutel 2014). The families Orsodacnidae and Megalopodidae, traditionally classified “close” to Chrysomelidae, were recently recovered as belonging to the cerambycoid lineage (Haddad et al. 2018) and resolved as either basal to other cerambycoid lineages or forming a clade with Vesperidae sister to Disteniidae+Cerambycidae. We fully concur with this classification, but both families are included here because they were not covered in the first part of Volume 6 of the Catalogue, and it would be superfluous to create a special volume for them especially because they share most of their references with chrysomelids. The higher classification of Megalopodinae follows Rodríguez-Mirón et al. (2021), though a phylogeny based on molecular data is urgently needed to verify their results. Classification of Galerucinae follows Douglas et al. (2023) with modification that the three tribes are treated here as supertribes, i.e. Alticitae, Galerucitae, and Serraticollitae to prevent diminishing the internal tribal classification of true galerucines. Genera transferred from alticines are listed as unassigned to tribes as their tribal position within Galerucitae was not resolved. The classification of Cryptocephalinae follows Gómez-Zurita & Cardoso (2021) who established the tribes Pachybrachini and Mylassini to solve the unsustainable situation of paraphyletic Cryptocephalini. However, the analysis did not include another crucial taxon – Acolastus Gerstaecker, 1855, which share the unique structure of the rectal apparatus with Clytrini. Accordingly, a new subtribe Acolastina of Clytrini is established here.

The present volume covers 761 valid genus-group names and 9498 valid species-group names. The family-group names currently in use are provided with their author and year when published; family synonyms or references to their original descriptions are not included. Type species are given in original combination for all genus-group taxa; in case of synonymy of the type species, the respective valid name is given in parentheses. All genus- and species-group taxa are provided with full reference, i.e. author, year and page where their description appeared. The lowercase prepositions such as French “de” and German “von” are not given with the author’s name in the list of taxa. In cases of descriptions in Chinese/Japanese with English translation, both respective pages where the descriptions appeared are given. Species-group taxa subsequently assigned to other genera are provided with their original genus in parentheses, following the page of publication. For species-group taxa proposed as entities lower than species (i.e. ssp., var., ab., forma, morpha, etc.), the original category is given in parentheses following the page and accompanied with the original combination where applicable. Unavailable and infrasubspecific names are listed alphabetically among other available names but not in italics. We find it useful for the reader to have all the names (both available and unavailable) summarized in one place. Taxa considered incertae sedis and nomina dubia are listed separately at the end of the nearest applicable taxon.

In the past, the same description was occasionally published twice, or even more times, in separate publications. In such cases, the earliest publication is referred to as indicated above, followed by an equals sign (=), and the year and page of the subsequent description(s) given in square brackets. The same style is used in cases where the name was available from the plate and the description appeared later. However, dual descriptions that appeared in the Bulletins of the French Entomological Society are ignored and only the oldest one is cited, for more details see the last paragraph in the Bibliographic Information chapter.

The following abbreviations, all given in square brackets following the page of publication, or the original combination when applicable, are used to provide taxonomic information:

All names that are deemed infrasubspecific based on the content of the work i.e., the same publication contained taxa given the status of subspecies as well as varieties, morphs etc., are infrasubspecific entities by definition (ICZN 1999, Art 45.6.4) and each infrasubspecific taxon is commented on in New Acts to avoid any further confusion or misapplication. However, a special case is Julius Weise’s monumental book on the Chrysomelidae of Germany, published in six consecutive parts (Lieferungen) within the series Naturgeschichte der Insecten Deutschlands (Weise 1881, 1882b, 1884d, 1886a, 1888b, 1893a). There are many varieties established in this book, however, in the third part (Lieferung 3) there is also a subspecies concept applied to the genus Oreina (see pp. 444, 447, 451, 462, 466, 476, 481) thus rendering all varieties as unavailable infrasubspecic taxa. For practical reasons and in the interests of stability, we decided to consider each of these parts as an independent publication for nomenclatural purposes and thus only the varieties published in the third part (pp. 369–568, Weise 1884d) are infrasubspecic, while those that appeared in other parts are available names. We believe that this better serves the stability of nomenclature, particularly considering that some of these variety names are currently used as valid species.

The New Acts chapter contains all the novel information with taxonomic and nomenclatural relevance presented in the Catalogue as well as additional comments. Each comment is numbered and cross-referenced with the respective place in the main text of the Catalogue. The New Acts chapter contains: all taxonomic and nomenclatural changes (new taxa, new substitute names, new synonymies, changes in rank, new combinations, nomina protecta, nomina oblita, type species and lectotype designations, corrections of authorship and spellings), information on infrasubspecific taxa, comments on distribution including new geographic records, and additional general comments when necessary.

The following abbreviations of institutions are used in the section New Nomenclatural and Taxonomic Acts, Comments and Distribution: