کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6431333 | 1635157 | 2014 | 14 صفحه PDF | دانلود رایگان |
- Santacrucian fossil localities prospected by Carlos Ameghino in 1887 are identified.
- Four localities at Rio Santa Cruz (Southern Patagonia) are formalized and described.
- The exposures represent the lower levels of the Santa Cruz Formation (Early Miocene).
- The geographic range of the Notohippidian Stage of Ameghino is expanded southwestward.
Between January and September of 1887 Carlos Ameghino carried out his first geologic and paleontological expedition to the RÃo Santa Cruz, Patagonia. Based on the fossils and geologic information compiled, in 1887 and 1889, Florentino Ameghino named more than 120 new species of extinct mammals and his Formación Santacruceña and Piso Santacruceño (Santacrucian stage). Data published by both brothers state that the specimens were collected in outcrops by the RÃo Santa Cruz, between 90 and 200Â km west of its mouth. However, information in the posthumously published letters and Travel Diary of C. Ameghino allows us to recognize a fourth locality, RÃo Bote, at about 50Â km further southwest. In 1900, 1902, F. Ameghino divided the Piso Santacruceño in a younger étage Santacruzienne and older étage Notohippidéen, restricting the geographical distribution of the latter to Kar Aiken locality, northeast of Lago Argentino. However, 15 of the 54 species that F. Ameghino listed as exclusively Notohippidian stage already had been named on specimens collected South to the RÃo Santa Cruz in 1887, two year prior to C. Ameghino's first visit to Kar Aiken. Based on historical information and several expeditions to the RÃo Santa Cruz and its environs, in this contribution we establish the geographical locations of the 1887 localities, formalize their names, evaluate the stratigraphic position of the fossil-bearing levels, and analyze the geographic extension of the Notohippidian, inferring that RÃo Bote is where C. Ameghino first collected species that came to define the Notohippidian.
Journal: Journal of South American Earth Sciences - Volume 52, July 2014, Pages 94-107