Phytophagy on fossil ferns from Argentina (Palo Pintado Formation, Late Miocene): a review of their fossil record and ichnotaxonomy

Abstract

-Evidence of insect-fern interactions are described for the fi rst time from late Miocene strata of Salta Province, Argentina. Two ichnospecies are defi ned to include fossil traces of surface feeding and hole feeding, located between the secondary veins and adjacent with the primary vein of two species of fossil ferns, Blechnum serrulatiformis Anzótegui & Horn and Thelypteris interrupta (Willd.) Iwatsuki. The fi rst ichnospecies corresponding with surface feeding presents oblong traces and both ends are rounded; occupying the entire intercostal space. This type of phytophagy is found for the fi rst time in the fossil record of ferns. The second ichnospecies is similar in shape and location to the previous ichnotaxon, except that all herbivorized tissues are absent. At last, a review of the fossil record of insect-fern associations is performed.Key words: insect-fern interactions, fossil traces, surface feeding, hole feeding.RESUMO -Descreve-se pela primeira vez evidência de interações inseto-samambaia no Mioceno superior da Província de Salta, Argentina. Duas icnoespecies são propostas para incluir rastros fósseis de alimentação superfi cial e alimentação em orifícios, localizadas entre as veias secundárias e adjacentes à veia primária em duas espécies de samambaias fósseis, Blechnum serrulatiformis Anzótegui & Horn e Thelypteris interrupta (Willd.) Iwatsuki. A primeira espécie corresponde à alimentação superfi cial, apresenta rastros oblongos com ambos os extremos arredondados e ocupa todo o espaço intercostal. Este é o primeiro registro de alimentação superfi cial em samambaias fósseis. A segunda espécie similar na sua forma e localização ao icnotáxon previamente descrito, exceto que todas as camadas de tecido herbivorizado estão ausentes. Finalmente, uma revisão do registro fóssil das associações inseto-samambaia também é realizada.Palavras-chave: interação inseto-samambaia, traços fósseis, alimentação superfi cial, alimentação em orifício.

Eupolypod ferns with dryopteroid/thelypteroid traits from Arroyo Chacay (Huitrera Formation, Eocene), Río Negro Province, Argentina

“…Fossils assigned to Thelypteris interrupta (Willd.) Iwatsuki (Cyclosorus interruptus sensu Almeida et al, 2016) have been reported from the Miocene Palo Pintado Formation, Salta Province, Argentina (Robledo et al, 2015) and are comparable to the material here described.…”

The ghost of the Cretaceous terrestrial revolution in the evolution of fern–sawfly associations

“…However, the observed pattern is consistent with phytophagous "lineage sorting" during the post-Cretaceous-Paleogene recovery of terrestrial habitats. This scenario appears to be more consistent with the fossil record of phytophagous insects (see Donovan et al, 2014;Ding et al, 2015;Robledo et al, 2015). In this context, it is worth stressing that reconstruction of ancestral larval diets suggested eudicots as the ancestral larval diet for nodes that are estimated to be older than the diversification of eudicots (Ronquist et al, 2012).…”

Occurrence of Christella (Thelypteridaceae) in Southwest China and its indications of the paleoenvironment of the Qinghai–Tibetan Plateau and adjacent areas

“…eoproliferus has slightly lobed and nearly entire margins of pinnae and relatively narrow segments with thick mid‐vein. Robledo et al () found the first fern fossil record of Thelypteridaceae in the neotropics, which was clarified as Thelypteris interrupta (Willd.) Iwatsuki from the late Miocene of Argentina.…”