No refugium but a rapid recovery from the end-Cretaceous extinction for plant-insect associations in Patagonia

ARI IGLESIAS; CÚNEO RUBEN; DONOVAN MICHAEL; P WILF; LABANDEIRA CONRAD

Nature ecology and Evolution

Springer Nature

Año: 2016 vol. 1 p. 1 - 6

TheSouthern Hemisphere may have provided biodiversity refugia after the Cretaceous-Paleogene (K-Pg) mass extinction.However, in the terrestrial realm, there havebeen no extinction and recovery studies using well-dated macrofossil sites thatspan the latest Cretaceous (late Maastrichtian) and early Paleocene (Danian)outside Western Interior North America (WINA).Here, we analyze insect-feeding damage on 3646 fossil leaves from the latestMaastrichtian and three time slices ofthe Danian in Chubut, Patagonia, Argentina (paleolatitude ca. 50° S). We testthe southern refugial hypothesis and the broader hypothesis that the extinctionand recovery of insect herbivores, a central component of terrestrial food webs,differed significantly from WINA at locations far south of the Chicxulub,Mexico impact structure. We find greater insect-damagediversity in Patagonia than in WINA during both the Maastrichtian and Danian,indicating a previously unknown insect richness. As in WINA, total diversity ofPatagonian insect damage decreased from the Cretaceous to Paleocene, butrecovery to pre-extinction levels occurred within ca. 4 my, compared with ca. 9my in WINA.As for WINA, there is no convincing evidence for survival of any of the diverse Cretaceous leaf mines in Patagonia,indicating a severe K-Pg extinction of host-specialized insects and norefugium. However, a striking difference from WINA is that diverse, novel leaf mines are present at all Daniansites, demonstrating a considerably more rapid recovery of specializedherbivores and terrestrial food webs. Our results support the emerging idea oflarge-scale geographic heterogeneity in extinction and recovery from theterminal Cretaceous catastrophe.