The spectacular radiation of insects has produced a stunning diversity of phenotypes. During the past 250 years, research on insect systematics has generated hundreds of terms for naming and comparing them. In its current form, this terminological diversity is presented in natural language and lacks formalization, which prohibits computer-assisted comparison using semantic web technologies. Here we propose a Model for Describing Cuticular Anatomical Structures (MoDCAS) which incorporates structural properties and positional relationships for standardized, consistent, and reproducible descriptions of arthropod phenotypes. We applied the MoDCAS framework in creating the ontology for the Anatomy of the Insect Skeleto-Muscular system (AISM). The AISM is the first general insect ontology that aims to cover all taxa by providing generalized, fully logical, and queryable, definitions for each term. It was built using the Ontology Development Kit (ODK), which maximizes interoperability with Uberon (Uberon multispecies anatomy ontology) and other basic ontologies, enhancing the integration of insect anatomy into the broader biological sciences. A template system for adding new terms, extending, and linking the AISM to additional anatomical, phenotypic, genetic, and chemical ontologies is also introduced. The AISM is proposed as the backbone for taxon-specific insect ontologies and has potential applications spanning systematic biology and biodiversity informatics, allowing users to: 1) use controlled vocabularies and create semiautomated computer-parsable insect morphological descriptions; 2) integrate insect morphology into broader fields of research, including ontology-informed phylogenetic methods, logical homology hypothesis testing, evo-devo studies, and genotype to phenotype mapping; and 3) automate the extraction of morphological data from the literature, enabling the generation of large-scale phenomic data, by facilitating the production and testing of informatic tools able to extract, link, annotate, and process morphological data. This descriptive model and its ontological applications will allow for clear and semantically interoperable integration of arthropod phenotypes in biodiversity studies.

The Caribbean weevil genus Apodrosus Marshall, 1922 is revised, including a redescription of A. argentatus Wolcott, 1924 and A. wolcotti Marshall, 1922 and description of 11 new species: A. adustus, sp.n. (Bahamas), A. andersoni, sp.n. (Dominican Republic), A. artus, sp.n. (Dominican Republic), A. earinusparsus, sp.n. (Dominican Republic), A. empherefasciatus, sp.n. (Bahamas), A. epipolevatus, sp.n. (Puerto Rico), A. eximius, sp.n. (Dominican Republic), A. mammuthus, sp.n. (Mona Island, Turks and Caicos Islands), A. quisqueyanus, sp.n. (Dominican Republic), A. stenoculus, sp.n. (Dominican Republic) and A. viridium, sp.n. (Dominican Republic). A key to the species and illustrations of external and internal structures are provided. Apodrosus is characterized as a monophyletic group by two unreversed synapomorphies – i.e., the presence of a median fovea on the apex of abdominal sternum VII and a J- or Y-shaped spermatheca – and is furthermore differentiated from related taxa by a unique combination of diagnostic features including the presence of premucro, a complete tegminal plate in males, the absence of longitudinal sclerites in the genital chamber of females, and an apical projection on the spermathecal cornu. A phylogenetic reconstruction of 20 taxa (7 outgroup, 13 ingroup) and 25 morphological characters yielded a single most parsimonious cladogram (L=61 steps, CI=42, RI=74) with the ingroup topology (A. artus, (A. andersoni, (A. earinusparsus, (A. epipolevatus, A. wolcotti)))), (A. eximius, ((A. argentatus, A. mammuthus), (A. viridium, (A. stenoculus, (A. quisqueyanus, (A. adustus, A. empherefasciatus)))))). The phylogeny indicates that Anypotactus bicaudatus Champion (Anypotactini Champion) is the sister group to Apodrosus, thereby calling into question the traditional tribal placement of this genus in the Polydrusini. The host plant associations of most species remain uncertain. A reconstruction of the historical biogeography of Apodrosus suggests that post-GAARlandia (Greater Antillean+Aves Ridges land span) vicariance was an important factor in the diversification of the higher-elevation inhabiting A. artus-A. wolcotti clade. Conversely, the species richness of the lower-elevation inhabiting A. eximius-A. empherefasciatus clade is most plausibly explained through a series of independent and likely more recent colonization events from the ancestral source area of southwestern Hispaniola to several smaller western Caribbean islands, or – in the case of Hispaniola – within-island areas of endemism.

The genus Lachnopus Schoenherr (Coleoptera : Curculionidae : Entiminae : Geonemini Gistel), with 66 species described to date, is the largest and most widespread entimine weevil genus in the Caribbean region. The monophyly and internal phylogenetic composition of Lachnopus are tested, using a cladistic analysis of 61 adult morphological characters of 31 ingroup species and five outgroup taxa representing the genera Diaprepes Schoenherr, Exophthalmus Schoenherr, Pachnaeus Schoenherr (all Eustylini), Ischionoplus Chevrolat (Geonemini) and Apodrosus Marshall (Polydrusini). The analysis produced two most parsimonious cladograms with a length of 167 steps, a consistency index of 36 and a retention index of 73. According to the strict consensus and preferred character state optimisations, the examined species of Lachnopus do not form a monophyletic entity, even though most species are placed in a major L. coffeae–L. guerinii ingroup clade, which stands in sister relationship to Ischionoplus. This major clade is constituted by at least three well-recognisable subgroups, each associated with a particular geographic range in the Caribbean region: (1) a widely distributed L. coffeae–L. lineicollis ‘grade’; (2) the Hispaniolan L. proteus–L. mercator clade; (3) and the L. hispidus–L. guerinii clade with species from Cuba, Florida and Jamaica. This study provides a sound phylogenetic basis for future revisions of Lachnopus and related geonemine genera.

The cosmopolitan subfamily Acidocerinae (Coleoptera: Hydrophilidae) is one of the largest and most taxonomically challenging lineages of water scavenger beetles. Recent phylogenetic studies have substantially advanced our understanding of acidocerine relationships but also illuminated the twin challenges of poorly delineated generic concepts and a classification broadly incompatible with the phylogeny. Here, these two challenges are addressed by providing a comprehensive synthesis and taxonomic tools for the Acidocerinae, including (1) a brief history and the current state of acidocerine classification, (2) a review of acidocerine ecology and collection methods, (3) the current knowledge of larval and fossil acidocerines, (4) a morphological primer on characters of taxonomic and systematic importance within the lineage, (5) a key to the world genera of Acidocerinae, (6) diagnoses, habitus, and aedeagal images, distribution maps, and summary of knowledge for each of the 23 extant genera in the subfamily, and (7) a complete annotated taxonomic catalog including the published distributions, synonyms, and references for all described 541 acidocerine species recognized as of 1 April 2021. The following nomenclatural acts are proposed to bring the phylogeny and classification into alignment: Colossocharesgen. nov. is established to accommodate two African species previously described as Helochares (s. str.); Novocharesgen. nov. is newly established to accommodate 15 Neotropical species previously included in Helochares (s. str.); the remaining Helochares subgenera Helocharimorphus Kuwert syn. nov. and Hydrobaticus MacLeay syn. nov. are synonymized with Helochares Mulsant. Peltochares Régimbart sensu nov. is redefined to include eight Old World species previously included in Helochares (s. str.). A lectotype is designated for Peltochares conspicuus Régimbart, the type species of the genus. The taxonomic and morphological circumscription of Helocharessensu nov. is narrowed and redefined.

Tok‐tokkies are one of the most iconic lineages within Tenebrionidae. In addition to containing some of the largest darkling beetles, this tribe is recognized for its remarkable form of sexual communication known as substrate tapping. Nevertheless, the phylogenetic relationships within the group remain poorly understood. This study investigates the usefulness of female terminalia morphology for delimiting Sepidiini and reconstructing relationships among it. Data on the structure of the ovipositors, genital tubes and spicula ventrali have been generated for >200 species representing 28 Pimeliinae tribes. This dataset was used in a comparative analysis at the subfamilial level, which resulted in recognition of several unique features of tok‐tokkie terminalia. Additionally, new features linking phenotypically challenging tribes also were recovered (Cryptochilini + Idisiini + Pimeliini). Secondly, 23 characters linked to the structure of female terminalia were defined for tok‐tok beetles. Cladistic analysis demonstrates the nonmonophyletic nature of most of the recognized subtribes. The morphological dataset was analysed separately and in combination with available molecular data (CAD, Wg, cox1, cox2, 28S). All obtained topologies were largely congruent, supporting the following changes: Palpomodina Kamiński & Gearner subtr.n. is erected to accommodate the genera Namibomodes and Palpomodes; Argenticrinis and Bombocnodulus are transferred from Hypomelina to Molurina; 153 species and subspecies previously classified within Psammodes are distributed over three separate genera (Mariazofia Kamiński nom.n., Piesomera stat.r., Psammodes sens.n.). Psammodes sklodowskae Kamiński & Gearner sp.n. is described. Preliminary investigation of the ovipositor of Mariazofia basuto (Koch) comb.n. was carried out with the application of microcomputed tomography, illuminating the muscular system as a reliable reference point for recognizing homologous elements in highly modified ovipositors.