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

Abstract. Palynological analysis of the Chigua and Maliman formations of Devonian and Early Carboniferous age respectively, cropping out in the Rio 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: Apiculiretusisporalaxa from the Devonian, and Pustulatisporitesmalimanensis from the Early Carboniferous. Two new combinations are proposed: the spore species Apiculatisporiscastanea (Butterworth and Williams) nov. comb., and the paleomicroplankton species, Dictyotidiummunificum (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 Potonie and Lele is emended. Twelve species are first recorded in the Devonian of South America, such as Pulvinosphaeridiumtrifidum Kiryanov, Dictyotidiumgranulatum Playford in Playford and Dring, Dictyotidiumvenulosum (Playford) Colbath, Orygmahapsispachyderma Colbath, Polyedryxiumleptum Turner, Leiotriletestrivialis Naumova, Granulatisporitesmuninensis Allen, Dibolisporitesvarius Tiwari and Schaarschmidt. Other spore species are first recorded in the Lower Carboniferous of South America, amongst them are cited Granulatisporitestriconvexus Staplin, Pustulatisporitespapillosus (Knox) Potonie and Kremp, Verrucosisporitesmicrotuberosus (Loose) Smith and Butterworth, Dibolisporitesmedaensis (Playford) Playford, Anapiculatisporitesampullaceus (Hacquebard) Playford, Lophotriletesseverus Playford and Satterthwait, Raistrickiagemmifera Playford and Satterthwait and Convolutisporatuberculata (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. Resumen. PALINOLOGIA DE LAS FORMACIONES CHIGUA (DEVONICO) Y MALIMAN (CARBONIFERO) EN LA SIERRA DEL VOLCAN,PROVINCIA DE SAN JUAN, ARGENTINA. PARTE I. PALEOMICROPLANCTON Y ESPORAS ACAVADAS LISAS Y ORNAMENTADAS. Se presenta el analisis sistematico de las asociaciones palinologicas obtenidas de sedimentitas de las formaciones Chigua y Maliman, del Devonico y Carbonifero Inferior respectivamente, aflorantes en la cuenca Rio Blanco. En esta primera parte se ilustran 35 especies de paleomicroplancton y 68 especies de esporas acavadas presentes en ambas formaciones. Se proponen dos nuevas especies de esporas, una del Devonico denominada Apiculiretusisporalaxa sp. nov. y la otra del Carbonifero Temprano, Pustulatisporitesmalimanensis. Se proponen tambien dos nuevas combinaciones, la espora Apiculatisporiscastanea (Butterworth y Williams) nov. comb., y una especie de paleomicroplancton, Dictyotidiummunificum (Wicander y Wood) nov. comb. basada en la discusion de los caracteres diagnosticos que permiten distinguir los generos Dictyotidium, Muraticavea, Polyedryxium y Cymatiosphaera entre si. El genero Quadrisporites Hennelly ex Potonie y Lele es enmendado. Doce especies son registradas por primera vez en el Devonico de America del Sur, entre ellas Pulvinosphaeridiumtrifidum Kiryanov, Dictyotidiumgranulatum Playford en Playford y Dring, Dictyotidiumvenulosum (Playford) Colbath, Orygmahapsis pachyderma Colbath, Polyedryxiumleptum Turner, Leiotriletestrivialis Naumova, Granulatisporitesmuninensis Allen, Dibolisporitesvarius Tiwari y Schaarschmidt. En tanto otras son registradas por primera vez en el Carbonifero Inferior de America del Sur, entre ellas Granulatisporitestriconvexus Staplin, Pustulatisporitespapillosus (Knox) Potonie y Kremp, Verrucosisporitesmicrotuberosus (Loose) Smith y Butterworth, Dibolisporitesmedaensis (Playford) Playford, Anapiculatisporitesampullaceus (Hacquebard) Playford, Lophotriletesseverus Playford y Satterthwait, Raistrickiagemmifera Playford y Satterthwait y Convolutisporatuberculata (Waltz) Hoffmeister, Staplin y Malloy. Los registros geograficos y estratigraficos previos mundiales de las especies aqui tratadas son reunidos en un cuadro mientras que solo los correspondientes a America del Sur figuran en el texto.