Abstract

AMENABAR, Cecilia R.; DI PASQUO, Mercedes; CARRIZO, Hugo A.  and  AZCUY, Carlos L.. 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. Ameghiniana [online]. 2006, vol.43, n.2, pp.339-375. ISSN 1851-8044.

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. Twelve species are first recorded in the Devonian of South America, such as Pulvinosphaeridium trifidum Kiryanov, Dictyotidium granulatum Playford in Playford and Dring, Dictyotidium venulosum (Playford) Colbath, Orygmahapsis pachyderma Colbath, Polyedryxium leptum Turner, Leiotriletes trivialis Naumova, Granulatisporites muninensis Allen, Dibolisporites varius Tiwari and Schaarschmidt. Other spore species are first recorded in the Lower Carboniferous of South America, amongst them are cited Granulatisporites triconvexus Staplin, Pustulatisporites papillosus (Knox) Potonié and Kremp, Verrucosisporites microtuberosus (Loose) Smith and Butterworth, Dibolisporites medaensis (Playford) Playford, Anapiculatisporites ampullaceus (Hacquebard) Playford, Lophotriletes severus Playford and Satterthwait, Raistrickia gemmifera Playford and Satterthwait and Convolutispora tuberculata (Waltz) Hoffmeister, Staplin and Malloy. Previous worldwide geographic and stratigraphic records of the species studied herein are charted, while those corresponding to South America are cited in the text.

Keywords : Palynology; Chigua and Malimán formations; Middle Devonian and Early Carboniferous; San Juan Province; Argentina.