Phyllocnistis furcata sp. nov.: a new species of leaf-miner associated with Baccharis (Asteraceae) from Southern Peru (Lepidoptera, Gracillariidae)

Oldest leaf mine trace fossil from East Asia provides insight into ancient nutritional flow in a plant-herbivore interaction

The Late Triassic saw a flourish of plant–arthropod interactions. By the Late Triassic, insects had developed all distinct strategies of herbivory, notably including some of the earliest occurrences of leaf-mining. Herein we describe exceptionally well-preserved leaf-mine trace fossils on a Cladophlebis Brongniart fern pinnule from the Momonoki Formation, Mine Group, Japan (Middle Carnian), representing the oldest unequivocal leaf-mines from East Asia. The mines all display a distinctive frass trail—a continuous meandering line, which later becomes a broad band containing spheroidal particles—demonstrating larval development. Although the shapes of the frass trails are generally comparable to those of Lepidoptera or Coleoptera, they cannot be unequivocally assigned to a specific extant leaf-mining taxon. Furthermore, elemental analyses by X-ray fluorescence (XRF) reveals that the frass trail comprises phosphate coprolites. The quantitative variations in P, S, and Si between coprolites and leaf veins may reflect physiological processes (e.g., consumption, absorption, and excretion) mediated by plant chemicals. Our findings reinforce the idea that leaf-mining had become a pervasive feeding strategy of herbivorous insects by the Late Triassic.

A contribution to the knowledge of leaf-mining Phyllocnistis Zeller, 1848 associated with Baccharis (Asteraceae), with description of two new species from Peru (Lepidoptera: Gracillariidae)

We provide new information on Neotropical Phyllocnistis Zeller (Gracillariidae) associated with Baccharis (Asteraceae) in the Andes region. Two new species are described, P. canta Cerdeña & Farfán, n. sp. and P. elongata Cerdeña & Farfán, n. sp., from the western slopes of the Andes of Peru between 2,000 and 3,000 m elevation, both associated with Baccharis latifolia (R.&P.) Pers. The type locality of P. baccharidis Hering is confirmed; immature stages were found at 1,300 m feeding on Baccharis tucumanensis Hook. & Arn. in Quebrada las Higueras (Tucumán, Argentina). Four new locality records for P. furcata Vargas & Cerdeña are provided, extending its distribution by 450 km to the north of the type locality.