Upper Cretaceous trace fossils in permineralized plant remains from Patagonia, Argentina

Abstract

Four new ichnogenera and six new ichnospecies are described from permineralized plant remains from an unnamed Upper Cretaceous formation, of northern Patagonia in Argentina. This association of traces is the second ichnocenosis described for permineralized wood. Traces are interpreted as insect borings in wood and fruits. Cycalichnus garciorum n. ichnosp. is the first trace fossil recorded in a cycad stem and the oldest known evidence of a termite nest for the southern hemisphere. Stipitichnus koppae n. ichnosp. is the first trace fossil recorded in a palm stem. Xylonichnus trypetus n. ichnosp. is interpreted as borings of beetles in conifer wood. Carporichnus maximus n. ichnosp., C. bertheorum n. ichnosp., and C. minimus n. ichnosp. represent the first ichnocenosis related with a single species of fruit, and the only known Mesozoic borings in fruits. An historical overview of insect traces in permineralized wood shows that most were described ignoring the ichnological aspects, and this resulted in the absence of a taxonomic classification. In this paper, the main ichnotaxobases to describe insect traces in petrified wood are proposed for the first time.

Key words:

• trace fossils
• insect borings
• permineralized wood
• Cretaceous
• Argentina