First fossil record of the primitive family Acanthopteroctetidae from Myanmar amber (Lepidoptera, Glossata)

In extant Lepidoptera, the phylogenetically most ancient species have a unique character in common: the homoneurous wing venation (= similar venation in both wing pairs). This is a plesiomorphic trait occurring in ten families, which are summarised under the term “primitive Lepidoptera” or “primitive moths”. Species from these families are relicts of a fauna from a distant past reaching back to the Triassic. Taken together the group comprises less than 0.05% of the extant members of the order. Only in recent years, representatives of three of these families were discovered as fossils from Myanmar amber: Agatiphagidae, Heterobathmiidae and Lophocoronidae (Mey et al., 2021; Mey, 2024). Now, a further family can be added: Acanthopteroctetidae. The record is based on a single male, also found in Myanmar amber. Contemporary species of this family are tiny insects, whose larvae are leaf-miners. The fossil species is also a minute insect with a forewing length of about 2 mm. It was assigned tentatively to Acanthopteroctetidae by observing the presence of two diagnostic characters of the family: fusion of M1 with RS in fore- and hindwings and spur formula 0.1.4. of the legs. However, the male genitalia and other characters differ significantly from those of extant species and necessitates the establishment of a new genus, and even of a new subfamily.