New evidence of plant-insect interactions in the Lower Permian from Western Gondwana

Abstract

A new record of insect damages-containing glossopterid leaves is recovered from the Rio da Estiva outcrop, Itaiópolis country, northernmost Santa Catarina State, southern Brazil. The plant fossil-bearing strata are situated, stratigraphically, from the basal to middle part of the Rio Bonito Formation, a unit of the Lower Permian sequence of the Paraná Basin. This plant assemblage is characterized as “pure Glossopteris Flora”, and contains remains of glossopterid leaves (Glossopteris spp. and Gangamopteris sp.), seeds (Samaropsis sp. and Cordaicarpus sp.) and fructification (Ottokaria sp.). We analyzed 102 samples, of which only ten showed evidence of insect damages. Three types of leaf feeding traces are observed: leaf margin feeding traces, hole feeding traces and trench feeding traces. The damages occurred in leaves of Glossopteris sp., Glossopteris communis, Glossopteris occidentalis and Gangamopteris obovata. The evidence of consumption of foliar tissues indicated that glossopterids hosted a functional feeding group of predominantly chewing and sucking type of insects. The differences found in the patterns and frequencies of consumption in different localities of equivalent ages suggested that herbivory was more intensive in some plant communities than in others. Besides this, the present study expanded geographically the distribution of records of plant-insect interactions in “Glossopteris flora” through the central portion of the eastern rim of Paraná Basin.