Equisetites pusillus sp. nov. from the Aptian of Patagonia, Argentina

Abstract

Compressions of fertile equisetacean branches belonging to the new species Equisetites pusillus are described using light microscopy. The specimens were collected at the Estancia Bajo Tigre locality in strata referred to the Anfiteatro de Ticó Formation, Baqueró Group (Aptian) from the Santa Cruz province, Argentina. The fertile stems bear an oval and solitary terminal cone with spores. The spores are alete, circular and without elaters. Equisetites pusillus sp. nov . is compared with other fossil equisetacean taxa from Argentina and elsewhere. The spores are compared with those of two extant Equisetum species from Argentina, and also with other mesozoic taxa. The compressions were found in sediments rich in organic matter, deposited in shallow waters surrounded by environments colonized by sphenophytes, ferns and bryophytes. This type of landscape was frequent during the Aptian originating a common type of deposit (lenticular) in the Anfiteatro de Ticó Formation.