Millerocaulis (Erasmus) ex Tidwell (Osmundales, Filices) de la Formación Carrizal (Triásico Superior) de Marayes, provincia de San Juan, Argentina

• Autores: Rafael Hersbt
• Localización: Revista del Museo Argentino de Ciencias Naturales, ISSN-e 1853-0400, ISSN 1514-5158, Vol. 8, Nº. 2, 2006, págs. 185-193
• Idioma: español
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• Resumen

  • Millerocaulis (Erasmus) ex Tidwell (Osmundales, Filices) from the Carrrizal Formation(Upper Triassic) from Marayes, San Juan province, Argentina. Based on newly found specimens, «Marayealutzi» Herbst 1994, of the Upper Triassic Carrizal Formation, from Marayes (San Juan province , Argentina) isanalyzed. Anatomical characters, specially those from the central cylinder, now defines the species as an ectophloicdictyoxylicsiphonostele (sensu Miller) and shows that it must be changed to Millerocaulis. Thus, Marayeadefined as a siphonostelic genus becomes invalid and an emended diagnosis for the type species is given. Also,from the same locality and age other, rather big specimens, are described. They are not well preserved but theavailable characters allow to incorporate them as Millerocaulis sp. These two species and others formerly describedof this genus, M. herbsti (Archangelsky & de la Sota) Tidwell and M. stipabonettii Herbst, from the LagunaColorada Formation (Santa Cruz province) and Cepeda Formation (San Juan province) respectively from Argentinaalong with M. beardmorensis Schopf and Ashicaulis woolfei Rothwell, Taylor & Taylor, from the FremouwFormation (Antarctica) and the frond Osmunda claytoniites Phipps et. al.,as well as some petioles lacking cellularstructure but undoubtely belonging to Millerocaulis, from the Los Rastros Formation (San Juan province), allfrom the upper Middle to Upper Triassic, show the diversification of the Osmundales as early as this time span,at least in this part of Gondwana