Palynology of the Chigua (Devonian) and Malimán (Carboniferous) formations in the Volcán Range, San Juan Province, Argentina. Part I. Paleomicroplankton and acavate smooth and ornamented spores

AMENÁBAR, CECILIA R., DI PASQUO, MARÍA DE LAS MERCEDES, CARRIZO, HUGO A., AZCUY, CARLOS L.

AMEGHINIANA

Asociación Paleontológica Argentina

Lugar: Ciudad Autónoma de Buenos Aires; Año: 2006 vol. 43 p. 339 - 375

0002-7014

Palynological analysis of the Chigua and Malimán formations of Devonian and Early Carboniferous age respectively, cropping out in the Río Blanco Basin, northwestern Argentina, has yielded diverse paleomicroplankton-spore assemblages. In this first part, 35 species of paleomicroplankton and 68 species of acavate spores from both formations are illustrated. Two new species are proposed: Apiculiretusispora laxa from the Devonian, and Pustulatisporites malimanensis from the Early Carboniferous. Two new combinations are proposed: the spore species Apiculatisporis castanea (Butterworth and Williams) nov. comb., and the paleomicroplankton species, Dictyotidium munificum (Wicander and Wood) nov. comb., based on the discussion of the main characters of the genera Dictyotidium, Muraticavea, Polyedryxium and Cymatiosphaera. The genus Quadrisporites Hennelly ex Potonié and Lele is emended. The following species are first recorded in the Devonian of South America: the acritarchs Micrhystridium sp. cf. M. pentagonale Stockmans and Willière, Pulvinosphaeridium trifidum Kiryanov, Cymatiosphaera sp. cf. C. subtrita Playford in Playford and Dring, Dictyotidium granulatum Playford in Playford and Dring, Dictyotidium venulosum (Playford) Colbath, Orygmahapsis pachyderma Colbath, Polyedryxium leptum Turner, and the spores Leiotriletes trivialis Naumova, Punctatisporites glaber (Naumova) Playford, Punctatisporites planus Hacquebard, Granulatisporites muninensis Allen, Dibolisporites varius Tiwari and Schaarschmidt. Other spore species are first recorded in the Lower Carboniferous of South America, such as Granulatisporites triconvexus Staplin, Pustulatisporites papillosus (Knox) Potonié and Kremp, Verrucosisporites microtuberosus (Loose) Smith and Butterworth, Cyclogranisporites lasius (Waltz) Playford, Dibolisporites medaensis (Playford) Playford, Dibolisporites sp. cf. D. setigerus Playford and Satterthwait, Anapiculatisporites ampullaceus (Hacquebard) Playford, Apiculatisporis castanea (Butterworth and Williams) nov. comb., Lophotriletes severus Playford and Satterthwait, Lophotriletes sp. A Playford and Satterthwait, Verrucosisporites baccatus Staplin, Raistrickia gemmifera Playford and Satterthwait, Raistrickia sp. cf. R. condylosa Higgs, Convolutispora tuberculata (Waltz) Hoffmeister, Staplin and Malloy, Convolutispora sp. cf. C. usitata Playford, Dictyotriletes trivialis Naumova in litt. in Kedo, and Emphanisporites hibernicus Clayton, Higgs and Keegan. Previous worldwide geographic and stratigraphic records of the species studied herein are charted, while those corresponding to South American are cited in the text.