Rhexoxylon piatnitzkyi and its ancient adversaries: deciphering plant-beetle interactions and its palaeoecological significance in the Ischigualasto Formation (Upper Triassic, Argentina)

Fossilized evidence from the Ischigualasto Formation reveals ancient interactions between the corystosperm plant Rhexoxylon piatnitzkyi and wood-boring beetles, likely early cerambycids. CT scans and thin sections exposed abundant galleries in branches, targeting secondary phloem and pith, while trunks showed fewer borings. The presence of fungal decay and tracheid fragments in frass suggests the beetle fed on both living and decayed wood. Anatomical features indicate the plant may have deployed defenses against both fungi and insects. This is the first record of insect galleries in corystosperm axes, offering insights into Triassic Gondwanan ecosystems.

Sagasti, A. J., Hernández Del Pino, S., & Bodnar, J. (2024). Rhexoxylon piatnitzkyi and its ancient adversaries: deciphering plant-beetle interactions and its palaeoecological significance in the Ischigualasto Formation (Upper Triassic, Argentina). Historical Biology, 37(4), 1078–1093. https://doi.org/10.1080/08912963.2024.2354962