Abstract

ZAMUNER, Alba B.  and  FALASCHI, Paula. Agathoxylon matildense n. sp., araucariacean wood from the cerro Madre e Hija Petrified forest, la Matilde Formation (Middle Jurassic), Santa Cruz province, Argentina. Ameghiniana [online]. 2005, vol.42, n.2, pp.339-346. ISSN 1851-8044.

The anatomy of a specimen from the Middle Jurassic of the cerro Madre e Hija area, La Matilde Formation, Santa Cruz province is presented. The anatomical characteristics observed allowed us to classify this specimen as a new member of the genus Agathoxylon : A . matildense n. sp. Distinct growth rings are observed in transversal sections while radial views show uniseriate tracheid pitting, contiguous and predominantly circular in shape, cross-fields are cupressoid with 4-5 pits irregularly arranged. Rays are homogeneous and very low (1-4 cells hight). Wood characters, its relationships with living related taxa and the associated fossil flora allow us to consider this wood as an Araucariaceae member. Agathoxylon matildense n. sp. probably grew under warm-temperate and humid climate with rainfall seasonality.

Keywords : Wood anatomy; Middle Jurassic; Argentina; Agathoxylon.