NEW ASTEROTHECACEAE FERNS FROM THE LA GOLONDRINA FORMATION (PERMIAN), SANTA CRUZ, ARGENTINA

CARIGLINO, B

Rio de Janeiro

Simposio; XIV Simposio Brasileiro de Paleobotanica e Palinologia; 2013

The La Golondrina Formation (Santa Cruz Province, Argentina) is known for bearing a rich Permian flora. Among its many elements, ferns (Division Pteridophyta) represent a large portion in both species number and abundance, accounting for a total of 16 species of 3 families (Asterothecaceae, Marattiaceae, Osmundaceae). Here, three new species of ferns assigned to the Asterothecaceae are presented. Asterotheca sp. 1 presents pinnas with smooth rachises. Contiguous pinnules (sub) oppositely attach to the rachis at approximately 90°. Pinnules are long, oblong, with straight parallel margins and rounded apex, with a length/width ratio of 3. Strong midvein runs straight from the base to almost the apex of pinnule, where it spreads in several apical veins. Secondary veins emerge from the midvein at 45° angle, and sometimes bifurcate once close to the midvein. Fertile pinnules have up to 10 small, circular synangia in a row at each side of the midvein without completely covering the underside of the pinnule. Asterotheca sp. 2 fronds are at least bi-pinnate, main rachis smooth or longitudinally striated. Pinnas attached alternately at angles between 65° to almost 90°. Apex of pinnas is slightly pointed, rachis smooth, sometimes punctuated. Pinnules are (sub) oppositely to alternately arranged at 60-70° to the rachis; they are small, wide at the base and short in length, with a rounded apex. Straight midvein runs up to the apex of the pinnule. Secondary veins emerge from the midvein at 45°, and reach the margin without dichotomizing. Fertile pinnules with 2 or 3 circular synangia at each side of the midvein (rarely 6 at each side observed), with 4 sporangia. Asterotheca sp. 3 fronds are at least bi-pinnate, main rachis smooth, sometimes striated or punctuated. Pinnas attached oppositely to sub-oppositely to the main rachis, at angles >50°. Pinnules attach oppositely at approximately 90° to the rachis; they are small and falcate. Midvein runs straight almost reaching to the apex. Secondary veins divide at least once. Fertile pinnules have up to 7-8 circular synangia at each side of the midvein, covering the entire underside of the pinnule. So far, comparisons with other Asterotheca previously recognized elsewhere in the world show that these species differ in their sterile and fertile characteristics. Provisional assignations are preferred until a greater detailed studio adding newly collected material is done, to ensure their allocations as new species. In case the three species are proved correct, this finding would increase the number of ferns known at La Golondrina Formation, as well as adding new species to the world list.