New floral elements from the cisuralian Arroyo Totoral formation (La Rioja Province, Argentina).

COTUREL, ELIANA P.; GUTIÉRREZ, PEDRO R.

Mendoza

Congreso; 4th International Palaeontological Congress; 2014

The aim of this contribution is to present several new taxa from the Permian Arroyo Totoral Formation fossil flora. This formation crops out in Sierra de los Llanos, La Rioja Province (Argentina), a wellknown Permian locality of the Paganzo Basin. Sedimentological profiles were logged at four localities (PF1, PF2, PF3, and PF5), and nine fossiliferous levels were recognized. A total of 21 taxa were identified: Asterotheca feruglioi, Paracalamites australis, Phyllotheca leptophylla, Botrychiopsis plantiana, Eusphenopteris sp., Arberia cf. minasica, Gangamopteris obovata, Glossopteris occidentalis, Glossopteris wilsonii, Cordaites hislopi, Ferugliocladus riojanum, Genoites sp., Ginkgophyllum sp., Eucerospermum sp., Cornucarpus sp., Samaropsis sp. A, Samaropsis sp. B, including the first mention for this formation of Paracalamites cf. frigidus, Cruciaetheca patagonica, Arberia cf. madagascariensis, and new species of Genoites and Asterotheca. Paracalamites cf. frigidus is different from any other sphenophyta stem known in the formation. Cruciaetheca patagonica is a sphenophyta with rows of sporangiophores and Phyllotheca-like foliage and, in spite of showing fewer rows of sporangiophores, it resembles the type species of the genus. Specimens referred to Arberia cf. madagascariens shows a basal bifurcation and a striated body, however, ovules are lacking. There is also a specimen of Glossopteris wilsonii with a long stalk attached to the petiole, and a polysperm similar to Arberia cf. madagascariensis in the extreme. In other specimen, dispersed polysperms are associated with a stalk. Genoites sp. nov. shows several ovules attached to the branch, axillar to leaves, and two kinds of foliage, different to the type species of this genus, Genoites patagonica. Asterotheca sp. exhibits partly fused pinnulae and a venation comparable to Asterotheca golondrinensis. A specimen referred to Asterotheca feruglioi bears synangia, still undescribed for this species; each sporangium is pyriform and displays a pointed apex; sporangia are fused at the base and free at the apex. The discovery of all these new taxa improves the knowledge of the Arroyo Totoral Formation flora, enhances its paleoecological knowledge, and refines the correlation between the Gangamopteris Biozone of Paganzo and the Gingkoites eximia Biozone of the Tepuel Genoa Basin.