Bárbara Cariglino

The lycophytes of the La Golondrina Formation (Permian), Santa Cruz Province, Argentina: systematic revision, biostratigraphy and palaeoecology

Cariglino, B., Coturel, E.P. & Gutiérrez, P.R., iFirst article, 2012. The lycophytes of the La Golondrina Formation (Permian), Santa Cruz Province, Argentina: systematic revision, biostratigraphy and palaeoecology. Alcheringa 36, 427–449. ISSN 0311-5518. The Permian lycophytes of the La Golondrina Formation (Santa Cruz province, Argentina) have remained unstudied for almost 50 years. This study reviews material described by Archangelsky in 1960 and increases the representation of specimens via new collections from the lower and middle members of the formation. The lycophytes, previously assigned to typical Laurasian genera, are re-analyzed and re-assigned to Gondwanan genera where appropiate. Two new lycophyte taxa, Bumbudendron patagonicum comb. nov. and Cyclodendron golondrinensis sp. nov. are proposed, and two specimens are retained under open nomenclature until better preserved material becomes available. Based on this study, the biostratigraphic range of Bumbudendron is extended to the Permian, whereas Cyclodendron remains a useful Permian stratigraphic index as previously suggested. Palaeoecological inferences derived from growth habit, floristic association and sedimentary facies indicate that these plants developed under micro- to meso-thermal, humid conditions.

The Paleobotanical Record of the Triassic Cerro de las Cabras Formation at Its Type Locality, Potrerillos, Mendoza (Uspallata Group): An Historical Account and First Record of Fossil Flora

Abstract. The first fossil macroflora assemblage from the Cerro de Las Cabras Formation at its type locality, in the Potrerillos area, is presented. The area is tectonically altered, which is why there have been several different interpretations about the real thickness and boundaries of the formation. A detailed analysis of the bibliography showed that previous fossil plant taxa referred to the Cerro de Las Cabras Formation belonged to the overlying Potrerillos Formation. However, the recent discovery of a plant-bearing level in stratigraphically constrained sediments of the Cerro de Las Cabras Formation allows the identification of a flora composed of Corystospermales —Dicroidium odontopteroides (Morris) Gothan; D. lancifolium (Morris) Gothan; D. crassum (Menéndez) Petriella; Zuberia zuberi (Szajnocha) Frengüelli; Z. sp. cf. Z. barrealensis Frengüelli—, Peltaspermales —Scytophyllum sp. cf. S. neuburgianum Dobruskina; Pachydermophyllum sp.; Peltaspermum sp.—, putative Gnetales — Gontriglossa sp.—, Osmundales —Cladophlebis mendozaensis (Geinitz) Frengüelli—, Equisetales, and two taxa of uncertain affinities. Although low in diversity, this assemblage is comparable to coeval assemblages in other basins, particularly the floras from the Agua de los Pajaritos, Barreal and Ischichuca formations, reinforcing the Middle Triassic age assigned by the vertebrate, microfloristic and radiometric dating.

The Palynology of the La Deheza Formation (Carboniferous—Permian; Upper Palaeozoic), Paganzo Basin, San Juan Province, Argentina

We present the first palynological study of the La Deheza Formation in Paganzo Basin, San Juan Province, Argentina. A total of 18 samples were studied and 116 palynomorph species were recorded. A multivariate statistical (R) analysis confirmed the occurrence of three associations. Assemblages 1 (240 m), 2 (230 m) and 3 (220 m) were referred to biozones already registered in the Paganzo Basin, i.e. Raistrickia densa—Convolutispora muriornata (DM), Pakhapites fusus—Vittatina subsaccata (FS) and Lueckisporites—Weylandites (LW) biozones. These assemblages can be assigned a Pennsylvanian—Cisularian age based on previous stratigraphic records of the identified species.

Permian glossopterid scale leaves from the La Golondrina Formation (Santa Cruz, Argentina): the neglected members of Glossopteris floras

Se describen y analizan escamas foliares de glossopterideas provenientes de la Formacion La Golondrina. Se reconocen tres tipos diferentes sobre la base de sus diferencias morfologicas y patrones de venacion. Las escamas foliares Tipo A presentan forma triangular; las venas centrales corren desde la base hasta el apice, con las venas laterales dicotomizandose una o dos veces antes de llegar a los bordes. Las escamas foliares tipo B tienen variadas formas; las venas centrales marchan en linea recta hacia el apice, dividiendose y anastomosandose varias veces, mientras que las venas laterales se arquean hacia los margenes, formando poligonos que se vuelven mas cortos y numerosos al llegar a los bordes. Por ultimo, las escamas foliares Tipo C presentan formas triangulares, romboidales o subcirculares, son escamas convexas, surcadas por venas rectas sub-paralelas que surgen desde la base y alcanzan el margen distal, ocasionalmente dicotomizandose cerca de los margenes. La parte media-inferior de estas escamas esta cubierta por un puntuado de origen incierto. La clasificacion artificial aqui propuesta es unicamente con el proposito de identificacion de estos elementos, y no implica necesariamente relaciones filogeneticas. Los diferentes tipos de escamas podrian haber actuado como proteccion de los brotes y/o partes fertiles o como dispersor de estas, una vez que estaban maduras