CONIFER FOSSIL WOODS FROM THE MID-CRETACEOUS (ALBIAN) KACHAIKE FORMATION, SANTA CRUZ PROVINCE, ARGENTINA

CARLOS GREPPI; PUJANA, ROBERTO; DANIELA RUIZ; COSME ROMBOLÁ; INÉS ARAMENDÍA

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2023

0002-7014

We describe 21 silicified woods from the Kachaike Formation (Albian, mid-Cretaceous), collected in the Tucu Tucu Ranch, west-central Santa Cruz Province, Argentinian Patagonia. The specimens are secondary xylem and the preservation varies among them. Anatomical studies indicate that they are conifers related to the families Araucariaceae and Cheirolepidiaceae, and are placed into two fossil species: Agathoxylon antarcticus and Brachyoxylon patagonicum. All the specimens studied show marked growth rings, indicating annual seasonality. Decay patterns similar to those produced by modern xylophagous fungi are also recognized. The presence of Araucariaceae and Cheirolepidiaceae allows a better understanding of the paleoflora of the Kachaike Formation, based previously only on palynological and fossil leaves studies. In addition, it provides additional information regarding the dominance of the tree canopy by conifers during the Cretaceous from Patagonia.