The world’s smallest moths in Lepidoptera (Insecta) and the complexity in making such a determination are examined and discussed. The forewing length and wingspan of 650 species were measured and the same data were retrieved from published papers to determine which species and family have the smallest moths in the world. The minimal recorded forewing length was found to be around 1.2–1.3 mm and the wingspan around 2.6–2.8 mm in two families, the Gracillariidae and Nepticulidae. Among Lepidoptera, the following species have the smallest moths globally: the European Johanssoniella acetosae (Stainton), the Peruvian Simplimorpha kailai Stonis & Diškus, the Mexican Stigmella maya Remeikis & Stonis, the Mediterranean S. diniensis (Klimesh), the Mediterranean Parafomoria liguricella (Klimesh) (Nepticulidae), the South East Asian Porphyrosela alternata Kumata, and the Central African P. desmodivora De Prins (Gracillariidae). Additionally, in the Nepticulidae, we provide a measurement update for Stigmella maya Remeikis & Stonis, one of the tiniest species with a forewing length of 1.3 mm and wingspan of 2.8 mm, and describe a new species, Stigmella incaica Diškus & Stonis, sp. nov., with a forewing length of 1.75 to 1.95 mm and a wingspan of 3.8 to 4.3 mm.

For the first time, genera of leaf mining Tischeriidae of the global fauna are reviewed and four new genera are described: Coptotrichoides Diškus & Stonis, gen. nov., trophically associated with Sapindaceae from Central and South America; Rytietia Diškus, Xu & Dai, gen. nov., trophically associated with Annonaceae from East and South East Asia; Pafazaria Diškus & Stonis, gen. nov., trophically associated with Fabaceae and Malvaceae from East and South East Asia; and Gnathitischeria Diškus, gen. nov., trophically associated with Malvaceae and Asteraceae from Central America. In addition to the descriptions of new genera, all previously described genera (Coptotriche Walsingham, 1890; Dishkeya Stonis, 2020; Tischeria Zeller, 1839; Manitischeria Diškus & Stonis, 2021; Neotischeria Diškus & Stonis, 2021; Paratischeria Diškus & Stonis, 2017; and Astrotischeria Puplesis & Diškus, 2003) are characterized and a pictorial identification key for all 11 genera is provided. Morphological and biological characteristics of all genera are supplemented with some molecular data. We described 12 new species: South East Asian Coptotriche sapaensis Diškus & Stonis, sp. nov.; Central American Coptotrichoides sapindoidum Diškus & Stonis, sp. nov. and Tischeria neokristenseni Diškus & Stonis, sp. nov.; South East Asian Rytietia uncinata Diškus, Xu & Dai, sp. nov., East Asian R. chongyiensis Xu & Dai, sp. nov.; South East Asian Pafazaria capitata Diškus & Stonis, sp. nov. and P. faboidica Diškus & Stonis, sp. nov.; Central American Neotischeria antigua Diškus & Remeikis, sp. nov. and N. subantigua Diškus & Remeikis, sp. nov.; South American Astrotischeria incae Diškus & Stonis, sp. nov.; and Central American Gnathitischeria atitlani Diškus & Stonis, sp. nov. and G. arcana Diškus & Stonis, sp. nov. The taxonomic rank of the East Asian subspecies Tischeria decidua siorkionla Kozlov, 1986 is elevated to species rank: T. siorkionla Kozlov (stat. nov.). The male genitalia of holotypes, paratypes, lectotypes or paralectotypes, or non-type specimens of some little-known species are examined for the first time. We provide the first morphological documentation for the following: Tischeria ceanothi lectotype and paralectotype; T. immaculata (stat. restored) paratype; Coptotrichoides deliquescens (Meyrick) lectotype and paralectotype; lectotypes of Coptotriche aenea (Frey & Boll), Astrotischeria plagifera (Meyrick), A. helianthi (Frey & Boll), and A. ephaptis (Meyrick); Coptotriche berberella (De Prins) paratype; and the first photographic documentation of Tischeria lvoskyi Kozlov holotype. Some non-type specimens deposited at NHMUK, including a few previously neglected species, are also examined and documented, including the American Astrotischeria solidagonifoliella (Clemens) and A. omissa (Braun). Nine new combinations are provided: Coptotrichoides deliquescens (Meyrick, 1915), comb. nov.; C. singularis (Stonis & Diškus) comb. nov.; C. suprafasciata (Diškus & Stonis) comb. nov., C. serjaniphaga (Remeikis & Stonis) comb. nov.; C. braziliensis (Diškus & Stonis) comb. nov.; Pafazaria jingdongensis (Xu & Dai), comb. nov.; Neotischeria explosa (Braun) comb. nov.; N. pallidipennella (Braun) comb. nov.; and Astrotischeria heteroterae (Frey & Boll) comb. nov. The synonymization of Tischeria longeciliata Frey & Boll, 1878 with Astrotischeria helianthi (Frey & Boll, 1878) is confirmed. One new species group, the Tischeria ceanothi group, is established. We also report a new distribution record of T. dodonaea Stainton from the Caucasus, Armenia. Three tables and 569 figures of adult external morphology, male and female genitalia, leaf mines, and cladograms based on molecular characters are provided.

We report on fourteen species and four genera of Tischeriidae recorded from Las Cuevas, a single tropical forest locality in Belize, Central America. This is the highest number of species of Tischeriidae recorded from a single locality worldwide, exceeding the species and generic diversity of the entire Tischeriidae fauna of Europe and accounting for about 9% of the documented global fauna for this family. We describe and name six new species: Astrotischeria papilloma Diškus & Stonis sp. nov., mining on Lasianthaea fruticosa (L.) K.M.Becker (Asteraceae); A. scutifera Diškus & Stonis sp. nov., mining on Sida glabra Mill. (Malvaceae); A. basilobata Remeikis & Stonis sp. nov., mining on Lasianthaea fruticosa; Paratischeria robinsoni Diškus & Stonis sp. nov., mining on Otopappus verbesinoides Benth. (Asteraceae); P. tubifex Diškus & Stonis sp. nov., mining on Lasianthaea fruticosa; and P. belizensis Remeikis & Stonis sp. nov. (host plant unknown). Additionally, we review eight previously described species from the same period of collecting at Las Cuevas in 1997–1998: A. selvica Diškus, Carvalho-Filho & Stonis, 2018, mining on Sphagneticola trilobata (L.) Pruski and Synedrella nodiflora (L.) Gaertn. (Asteraceae); A. casila Diškus & Stonis, 2018, mining on Montanoa atriplicifolia (Pers.) Sch.Bip. (Asteraceae); A. furcata Diškus & Stonis, 2018 (host plant unknown); Paratischeria neotropicana (Diškus & Stonis, 2015), mining on Sida L. (Malvaceae), including S. rhombifolia L.; Dishkeya gouaniae (Stonis & Diškus, 2007), mining on Gouania polygama (Jacq.) Urb. (Rhamnaceae); Coptotriche pulverea (Walsingham, 1897), mining on Terminalia amazonia (J.F.Gmel.) Exell (Combretaceae); C. forsteroniae Stonis & Diškus, 2008, mining on Forsteronia myriantha Donn Sm. (Apocynaceae); and C. singularis Stonis & Diškus, 2008 (host plant unknown). All taxa, except for C. singularis, are illustrated with photographs of the adults and their genitalia. We also briefly discuss the discovery of some novel characters for Astrotischeria Puplesis & Diškus, 2003 and Paratischeria Diškus & Stonis, 2017, Tischeriidae, and provide the first photographic documentation of Coptotriche pulverea and C. forsteroniae.

Our investigation centered on the tropical dry forests along the Pacific coast of Honduras, aiming to elucidate the presence and abundance of minuscule grey moths during the dry season. Through specimen dissections and the taxonomic identification of the collected material, we have described three new species: Acalyptris podenasi sp. nov., A. palpiformis sp. nov., and A. tortoris sp. nov. Additionally, we documented two species previously known from neighboring countries, A. lascuevella Puplesis & Robinson and A. basicornis Remeikis & Stonis. The females of A. lascuevella were previously unknown and are documented here for the first time. Morphological examinations were complemented by DNA barcoding, particularly highlighting variation in A. lascuevella. The paper’s primary significance lies not only in the description of new species but also in uncovering their taxonomic, morphological, and molecular importance. We found that these species are unique and indicative of the previously unstudied dry forests as a distinct ecosystem. Our findings revealed several novel atypical morphological traits within the studied Nepticulidae, including unusually large signum cells in the female genitalia, a dorso-ventrally divided uncus, and asymmetrical valvae in the male genitalia. These discoveries underscore the morphological diversity of Acalyptris Meyrick and their significance in evolutionary biology. Consequently, the paper addresses a previously unknown phenomenon of the occurrence and astonishing abundance of minuscule plant-mining micromoths in dry deciduous forests during the peak of the dry season. We hope that this paper will encourage Lepidoptera taxonomists to explore micromoths in other tropical dry forests, which, while limited in distribution, hold global importance. The paper is extensively illustrated with photographs of Acalyptris adults and their genitalia, along with maps, habitats, and molecular phylogenetic trees.

We review eighteen species of Nepticulidae (Lepidoptera: Nepticuloidea) from Asia and describe eleven new species from Central Asia and the western Himalaya: Stigmella ziziphifolia Rocienė & Stonis, sp. nov., S. damocles Remeikis, sp. nov., S. pyramidata Diškus & Navickaitė, sp. nov., S. alilediella Diškus & Navickaitė, sp. nov., S. longa Remeikis & Stonis, sp. nov., S. latilobata Diškus & Navickaitė, sp. nov., S. paniculata Diškus & Navickaitė, sp. nov., Ectoedemia orbiculata Diškus, Remeikis & Stonis, sp. nov., Acalyptris brunipexus Stonis, Diškus & Remeikis, sp. nov., A. noctilucus Rocienė & Stonis, sp. nov., and A. nasutus Diškus & Navickaitė, sp. nov. The new taxa are illustrated with photographs of the adults, their genitalia, and, if available, leaf mines. We also provide the first photographic documentation of adults and male genitalia of some Asiatic species. We synonymize E. petrosa Puplesis with E. spinosella (de Joannis), and E. rosiphila Puplesis with E. ingloria Puplesis.

This publication describes Dvidulopsis Stonis & Diškus, gen. nov., and a new species, D. diviantis Stonis & Remeikis, sp. nov., along with new distribution data for D. latipennata (Puplesis & Robinson) from Honduras. The study identifies Dvidulopsis gen. nov. as a distinct taxon, characterized by notable characters of the male genitalia, including a typically divided uncus and gnathos, and three elongated apical carinae of the phallus. Molecular evidence from new mtDNA COI-5’ sequences further supports the genus description. The new genus, comprising eight species, is endemic to lowland tropical humid forests, typically found at elevations of 10–400 m. Half of the known species inhabit equatorial regions, specifically the humid forests of the Amazon Basin, while the other half are found in the humid forests of Central America. The study also summarizes distribution data on Nepticulidae from the conservation-priority lowland tropical humid forests of the Neotropics, currently encompassing 57 species, representing approximately 30% of the described Nepticulidae fauna in the Neotropical region (sensu stricto). The article is illustrated with a chart depicting Nepticulidae occurrence in the lowland tropical humid forests of the Americas, a species distribution map, photographs of Dvidulopsis adults and male genitalia, and two molecular NJ trees distinguishing the new genus from similar taxa, such as Acalyptris Meyrick, 1921; Fomoria Beirne, 1945; and other Nepticulidae.