Tonco Valley (Miocene of Argentina)

Where: Salta, Argentina (25.4° S, 65.9° W: paleocoordinates 25.6° S, 63.9° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Palo Pintado Formation, Late/Upper Miocene (11.6 - 5.3 Ma)

• The mammalian remains described here come from the lower section of the Palo Pintado Fm. (Fig. 1b). In the Tonco Valley, this unit has a partial thickness of 176m, the basal contact is transitional with the Angastaco Formation and the upper contact is an erosional unconformity with Quaternary sediments.

•Fossiliferous levels= level 0-4 (numbered from bottom to top).

•The age of fossil-bearing levels is approximately between 8 and 7 Ma (Payrola et al. in prep). cor- responding to the late Tortonian or the Messinian/Tortonian boundary (Cohen et al., 2013).

•deposited between 10.29 ± 0.11 Ma (K/Ar) to 5.27 ± 0.28 Ma (206 P b/238U; Coutand et al., 2006; Carrapa et al., 2006; Galli et al., 2008, 2014).

• group of beds-level stratigraphic resolution

Environment/lithology: "floodplain"; fine-grained sandstone and lenticular, medium-grained conglomerate

• The characteristics of the sedimentary deposits suggest an anastomosing fluvial system in which the main channels scours through thick cohesive floodplain (Díaz, 1985, 1987; del Papa et al in prep.).
• It consists of fine to medium conglomerate and fine-grained sandstone to siltstone strata (Fig. 1b). The conglomeratic levels form lenticular to shallow lenticular beds with normal grading and trough e cross stratifica- tion suggesting high energy shallow channels. On the other hand, the fine-grained sediments consist of light brown siltstones to sandy siltstones with mottles, millimeter-scale nodules of gypsum and carbonate, bioturbation features, sporadically interbedded thin layers of medium-coarse sandstones.

•Fossiliferous levels numbered 0, 1, 2, and 3 located within the fine-grained floodplain setting. All findings there were made on flooding plains, and each deposit has an average thickness of 4 m. Level 4 corresponds to a high lenticular conglomeritic channel deposit immediately above level 3 (Fig. 1b)

Size classes: macrofossils, mesofossils

Collection methods: The fossil specimens described below are housed in the Vertebrate Paleontology collections of the Instituto de Bio y Geociencias del NOA (IBIGEO-CONICET), Salta Province, Argentina.

Primary reference: N. Zimicz, P. Payrola, and C. Papa. 2018. New, Late Miocene mammalian assemblage from the Palo Pintado Formation (Northwestern Argentina). Journal of South American Earth Sciences 81:31-44 [P. Mannion/M. Kouvari]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 197784: authorized by Philip Mannion, entered by Miranta Kouvari on 26.11.2018, edited by Kateryn Pino

Creative Commons license: CC BY (attribution)

Taxonomic list

Mammalia
 Notoungulata - Mesotheriidae
cf. Typotheriopsis sp. Cabrera and Kraglievich 1930 notoungulate
 Notoungulata - Interatheriidae
Protypotherium minutum Cabrera and Kraglievich 1931 notoungulate
 Notoungulata - Hegetotheriidae
Paedotherium minor Cabrera 1937 notoungulate
Paedotherium kakai Reguero et al. 2015 notoungulate
 Notoungulata - Toxodontidae
 Rodentia - Chinchillidae
Prolagostomus sp. Ameghino 1887 chinchilid
 Rodentia - Caviidae
cf. Procardiomys sp. Pascual 1961 caviomorph
 Rodentia - Abrocomidae
Protabrocoma sp. Kraglievich 1927 chinchilla rat
 Cingulata - Dasypodidae
Macrochorobates sp. Scillato Yané 1980 armadillo
Euphractinae "gen et sp. indet A" Winge 1923 armadillo
Euphractinae "gen et sp. indet B" Winge 1923 armadillo
Euphractinae "gen et sp. indet C" Winge 1923 armadillo
Chorobates villosissimus Reig 1958 armadillo
Macroeuphractus morenoi Lydekker 1894 armadillo
Vetelia sp. Ameghino 1891 armadillo
Vetelia gandhii Esteban and Nasif 1996 armadillo
Stenolaemata
 Cyclostomata - Cavidae