Cactivalva nebularia, gen. et sp. nov. (Lepidoptera: Gracillariidae): a new Weinmannia leaf miner from southern Brazil

Male, female, pupa, larva and egg of a new genus and species of Gracillariidae (Ornixolinae), Cactivalva nebularia Moreira & Vargas gen. et sp. nov., 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 Weinmannia paulliniifolia Pohl ex Ser. (Cunoniaceae) in high altitude cloud forest of northeast Rio Grande do Sul state. During the first two sap-feeding instars, the larva forms a serpentine mine in the lowest layer of the spongy parenchyma of a leaflet. After moulting to the third instar, it moves to another leaflet, forming a blotch mine within which the last three tissue-feeding instars complete development, feeding upon both spongy and palisade parenchyma. Pupation occurs outside the mine, within a cocoon built on the leaf surface. This is the third genus of gracillariid moths described from the Atlantic Forest, and the first gracillariid species ever known to be associated with the Cunoniaceae.