The species of genus Chasicotatus Scillato-Yané (Eutatini, Dasypodidae)

chasicotatus was originally described as a monotypic genus based on chasicotatus ameghinoi scillato-yané, 1979, from the upper member of arroyo chasicó formation (las barrancas member, late chasicoan). an additional species, chasicotatus peiranoi , was erected by esteban and nasif (1996). this work presents the description of two new species previously recognized but never published by scillato-yané (1982), with a study and description of the osteoderm's internal structure from three of four species of the genus. on this basis, the genus is revised and expanded diagnoses are provided for the previously known taxa, so that the species are clearly differentiated by internal and external osteodermal features. the geographical distribution of the species of genus chasicotatus supports advanced palaeoenvironmental hypotheses previously proposed by different authors.