Podocarpaceae woods (Coniferales) from middle Jurassic La Matilde formation, Santa Cruz province, Argentina

Abstract

The anatomy of Podocarpaceae petrified woods (Coniferales) from La Matilde Formation (Middle Jurassic), that crop out in the Gran Bajo de San Julián area, of Santa Cruz province, Argentina are studied. The following species are described: Podocarpoxylon feruglioi nov. sp., Podocarpoxylon austroamericanum nov. sp.; Circoporoxylon sanjuliense nov. sp. and Circoporopitys argentinum nov. gen. et. sp.. The first two morphogenera correspond to specimens based on their secondary xylem (tracheid pitting, cross-fields and ray characters), while Circoporopitys is defined considering features of the pith, primary and secondary xylem. Also, a new combination, Circoporopitys shanense (Sahni) is proposed. Comparisons are made with other Podocarpaceae species from Gondwana. Podocarpoxylon Gothan and Circoporoxylon Kräusel are recorded for the first time for the Argentine Jurassic. The growth ring information of the woods suggest that they developed under very favorable environmental conditions, with a warm and humid paleoclimate.