Revision of Two Spinicaudatan Species from the Cañadón Asfalto Formation (Jurassic), Patagonia Argentina.Re-examination under a scanning electron microscope (SEM) of the type material of the species described by Tasch and Volkheimer (1970) and Vallati (1986) was applied, as well as, new materials collected from different localities of the Las Chacritas Member from Cañadón Asfalto Formation (Argentina).  Morphological description and new SEM images of the ornamentation pattern revealed features on carapaces that had not been recognized previously. 
SEM
Revision of Two Spinicaudatan Species from the Cañadón Asfalto Formation (Jurassic), Patagonia Argentina.Re-examination under a scanning electron microscope (SEM) of the type material of the species described by Tasch and Volkheimer (1970) and Vallati (1986) was applied, as well as, new materials collected from different localities of the Las Chacritas Member from Cañadón Asfalto Formation (Argentina).  Morphological description and new SEM images of the ornamentation pattern revealed features on carapaces that had not been recognized previously. 
SEM