Male, female, pupa, larva and egg of a new genus and species of Gracillariidae (Gracillariinae), Spinivalva gaucha Moreira and Vargas from southern Brazil are described and illustrated with the aid of optical and scanning electron microscopy. A preliminary analysis of mitochondrial DNA sequences including members of related lineages is also provided. The immature stages are associated with Passiflora actinia, P. misera and P. suberosa (Passifloraceae), and build mines on the adaxial leaf surface. Initially the mines are serpentine in shape, but later in larval ontogeny become a blotch type. Although the larvae are hypermetamorphic as in other Gracillariidae, there is no sap-feeding instar in S. gaucha; the larva feeds on the palisade parenchyma, thus producing granular frass during all instars. Pupation occurs outside the mine; prior to pupating, the larva excretes numerous bubbles that are placed in rows on the lateral margins of the cocoon external surface. This is the second genus of gracillariid moth described for the Atlantic Rain Forest, and the second gracillariid species known to be associated with Passifloraceae.

Male, female and immature stages of Phyllocnistis tethys Moreira & Vargas sp. nov. (Lepidoptera; Gracillariidae) from the Atlantic Rain Forest, coastal mountains of southern Brazil, are described and illustrated, using both optical and scanning electron microscopy. A preliminary analysis of mitochondrial (COI) DNA sequences including putative members of congeneric species is also provided. The immature stages are associated with the passion vine Passiflora organensis (Passifloraceae). The hypermetamorphic, endophyllous larva has four instars; the first, second and third instars are sap-feeders, associated primarily with the spongy parenchyma, and construct a blotch mine in the lower surface of the lamina; the fourth, non-feeding (spinning) instar constructs a flimsy endophyllous cocoon at the end of the mine, where pupation occurs. This is the first species of Phyllocnistis Zeller described from Brazil, and the first leaf-mining gracillariid associated with Passifloraceae.

Gracillariidae (Lepidoptera) are commonly known by the leaf miner habit found in the larval stage of most species. By using worldwide, public databases on species diversity and DNA sequences available for extant gracillariid species, we determined changes in the rate of taxonomic species descriptions through time, mapped their spatial distributions, examined their phylogenetic diversification, and estimated the number of species yet to be described for the family in the Neotropics. We recovered 185 species, a number that is smaller than that found in any other biogeographic region. However, it was estimated that at least 3875 additional species remain to be described in the region. Phylogenetic diversification showed a pattern of expanding diversity. A few entomologists have been involved with gracillariid taxonomy in the Neotropics, having 39% of the species been described by a single taxonomist. In most of such cases, descriptions were based on the adults only. A few species have been described from biomes known to have some of the greatest diversity on earth, such as the Atlantic Forest. Thus, such a scenario results from low sampling and scarce taxonomic activity that has prevailed for this family of moths in the Neotropics. It may also be associated with their small body size and to the fact that gracillariids do not seem to be attracted to light traps as much as other moths, which make their collection and identification by non experts difficult. We also suggested scientific and political actions that could be adopted to overcome such an unfavorable scenario

Gracillariidae leaf miners include 1987 species of poorly studied micromoths for which the majority of the diversity has been described from temperate regions. The Neotropics harbors one of the richest faunas of Gracillariidae, but the rate of taxon descriptions has been slow because of limited sampling and taxonomic activity. In this illustrated catalogue, we provide, for the first time, 476 high resolution illustrations for the 201 species of named gracillariids occurring in the region and revise their classification, newly considering the family-group names Oecophyllembiini stat. nov., Marmarini stat. nov., and Parornichini stat. nov. as tribes of Phyllocnistinae, in the first two cases and Gracillariinae in the last case respectively. Two species, Sauterina hexameris (Meyrick, 1921) comb. nov. and S. phiaropis (Meyrick, 1921) comb. nov., are transferred to Sauterina from Gracillaria. By making taxonomic, distributional, molecular and biological data available in a concise form, we aim to facilitate taxonomic work on Neotropical gracillariids, and in turn to enhance studies in general on poorly studied organisms such as parasitoids from this biogeographical region.