Abstract
Millerocaulis (Erasmus) ex Tidwell (Osmundales, Filices) from the Carrrizal Formation (Upper Triassic) from Marayes, San Juan province, Argentina. Based on newly found specimens, «Marayea lutzi» Herbst 1994, of the Upper Triassic Carrizal Formation, from Marayes (San Juan province , Argentina) is analyzed. Anatomical characters, specially those from the central cylinder, now defines the species as an ectophloicdictyoxylic siphonostele (sensu Miller) and shows that it must be changed to Millerocaulis. Thus, Marayea defined 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 the available characters allow to incorporate them as Millerocaulis sp. These two species and others formerly described of this genus, M. herbsti (Archangelsky & de la Sota) Tidwell and M. stipabonettii Herbst, from the Laguna Colorada Formation (Santa Cruz province) and Cepeda Formation (San Juan province) respectively from Argentina along with M. beardmorensis Schopf and Ashicaulis woolfei Rothwell, Taylor & Taylor, from the Fremouw Formation (Antarctica) and the frond Osmunda claytoniites Phipps et. al.,as well as some petioles lacking cellular structure but undoubtely belonging to Millerocaulis, from the Los Rastros Formation (San Juan province), all from 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
Highlights
En esta contribución se establece la real filiación genérica de la planta descripta como Marayea lutzi Herbst (1994) que fuera diagnosticada como un estípite con estructura anatómica sifonostélica pero que, con el hallazgo de nuevos materiales demuestra pertenecer al género Millerocaulis (Erasmus) ex Tidwell
that it must be changed to Millerocaulis
Marayea defined as a siphonostelic genus becomes invalid
Summary
En esta contribución se establece la real filiación genérica de la planta descripta como Marayea lutzi Herbst (1994) que fuera diagnosticada como un estípite con estructura anatómica sifonostélica pero que, con el hallazgo de nuevos materiales demuestra pertenecer al género Millerocaulis (Erasmus) ex Tidwell. Los pecíolos densamente empaquetados no tienen expansiones estipulares; están constituidos por haces xilemáticos con forma de C y C-elongada, de 1-3 filas de células de ancho, en una masa de células parenquimáticas en la que se encuentran pequeños grupos de esclerénquima, irregularmente distribuidos.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
