Otozamites ornatus sp nov., a new bennettitalean leaf species from Patagonia, Argentina

Leaves of Otozamites ornatus sp. nov., belonging to the order Bennettitales, have been studied using light microscopy and scanning and transmission electron microscopy of their cuticles. The leaves occur in the Baquero Formation (Lower Cretaceous) of Santa Cruz Province, Argentina. Cuticular analysis of the leaves has determined the presence of a very ornamented abaxial epidermis with an alveolar ultrastructure in its lower sub-layer and sunken stomata protected by papillate subsidiary cells. The presence of these complicated epidermal structures are directly or indirectly associated with water stress, such as hot, dry, exposed sites that developed in this region of Patagonia towards the end of the Mesozoic. (C) 1999 Academic Press.