Abstract: 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 & Diskus, 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 Diskus & Stonis, sp. nov., with a forewing length of 1.75 to 1.95 mm and a wingspan of 3.8 to 4.3 mm.
TL;DR: A phylogeny of the family in cladistic sense is presented and discussed and current opinions about the phylogenetic position of the Nepticulidae and the division of the Heteroneura are reviewed and discussed.
Abstract: A revised classification of the Holarctic genera of Nepticulidae is provided. Eight genera belonging to the nominal subfamily are recognised and redefined. They are Enteucha Meyrick (= Johanssonia Borkowski, Artaversala Davis, Oligoneura Davis), Stigmella Schrank (including Astigmella Puplesis), Simplimorpha Scoble in the Nepticulini and Acalyptris Meyrick ( = Microcalyptris Braun, Niepeltia Strand), Trifurcula Zeller, Parafomoria Van Nieukerken, Bohemannia Stainton and Ectoedemia Busck in the Trifurculini. Trifurcula is divided into the subgenera Glaucolepis Braun (= Fedalmia Beirne), Levarchama Beirne and Trifurcula s.str. Ectoedemia is divided into the subgenera Etainia Beirne, Fomoria Beirne, Laqueus Scoble, Zimmermannia Hering and Ectoedemia s.str. The genera and subgenera are (re)described and data on biology and distribution are given. The species Simplimorpha promissa (Staudinger) and Acalyptris psammophricta Meyrick are redescribed. A phylogeny of the family in cladistic sense is presented and discussed. The monophyly of Ectoedemia is uncertain, and monophyly of the subgenus Fomoria could not be demonstrated. Current opinions about the phylogenetic position of the Nepticulidae and the division of the Heteroneura are reviewed and discussed. The biogeography and hostplant relationships of the family are reviewed.