Sigmodontinos (Mammalia: Rodentia) del Pleistoceno tardío del valle de Tafí (Tucumán, Argentina): taxonomía, tafonomía y reconstrucción paleoambiental

ORTIZ, P.; PARDIÑAS, U.F.J.

AMEGHINIANA

Lugar: Buenos Aires; Año: 2001 p. 3 - 26

0002-7014

Abstract.  LATE PLEISTCXBNE  S1CMOTX)NTINES  (MAMMALLA:  RODFNTIA)  FROM  THE  TAFI  VALLEY  (TumhN, AKGENTINA):  TAXONOMY,  TAPHONOMY ANI)  PAIFOFNVIRONMENTAL L<ECC)NSTRUCTION.  An exceptionaliy rich ro- dent assemblage of Lujaninn age (latest Pleistocene) at La  Angostura (26" 55' 30" S,  65"41' 50" W, Taf: va- lley, Tucuman province; 1900 n) above  sea level) provides the first evidence  of sigmodontine rodents  in the fossil  record  of  northwestern  Argentina.  Identified  taxa  are: Abroflrrix  ill~rteirs  Thomas,  Akodo,~  sp., Nrcrori~ys  cf. N. Iilct~ris  (Thomas), Oxynzycter~rs  cf. 0,  pnrariiensis Thomas, Oligoryzornys cf. 0.  fin7rscrric (W;~terIiouse),  Oii~oun/zoniys  cf. 0.  "lor~gicn~rdnl~rs"  (Bennett),  Alrdi~ronrys  ednx Thomas, Cnlorrr!/s  cf. C, /nirc/w- C.  nlrrsarli,rlis, Ncolorrr!/s  ebriosirs Thomas, Plr!/l/olis  sp., Reithrodo~i  airrilirs  (Fischer),  and  tTnJim!/s  poioelli Ortiz  el  nl.  These include  the  first  fossils of  the  genera Neotonr!ys  Thomas and  Andinorrays  Thomas  in Argentina. Taphonomic  analysis  indicates  that  the  assemblage  is  a  fossil  owl  pellet  accumulation. Consequently, it can be assumed to be a  biased representation of  the small mammal fauna of a relatively small area over a relatively brief time span. This association has no modern analogue because today the- se species live at different altitudinal  vegetation belts. The fauna indicates a  community from  the high-al- titude grassland ecotone, with elements of  the Yungas, l'una  and High Andeans. Temperatures may have been lower than today Although the species composition  is similar to  the modern sigmodontine  commu- nity  in the area, quantitative variations in proportional  representation can  be  attributed to Holocene cli- matic conditions and, probably, to tlm  impact of  human populations  in historical times.