Segundas Barrancas Blancas (SBB) - Estancia Cordón Alto (ECA1 & ECA2) (Miocene of Argentina)

Where: Santa Cruz, Argentina (50.3° S, 70.3° W: paleocoordinates 50.9° S, 64.7° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Santa Cruz Formation, Santacrucian (17.5 - 16.3 Ma)

• Segundas Barrancas Blancas (SBB; 16.47–15.3 Ma), with three sites, Estancia Cordón Alto1 (ECA), Estancia Cordón Alto2 (ECA2), and Estancia el Tordillo (EET);

• formation-level stratigraphic resolution

Environment/lithology: "floodplain"; lenticular, paleosol/pedogenic, silty sandstone

• Floodplain deposits with paleosols, Sheet flood – crevasse splay deposits and Fluvial channel deposits
• The SCF here in the SBB is composed of fine-grained sediments of FAs 1 and 2, although conspicuous lenticular sandstone bodies of FA3 are observed (Fig. 10). The sections are locally correlated using a tuff layer (CECA-2 tuff; Cuitiño et al., 2016) and tabular, laterally extensive and distinctive yellow beds (Figs. 10 and 11). The CECA-2 tuff layer is about 1 m thick (Fig. 10.3) and was dated at the EET1 Section by Cuitiño et al. (2016) with an age of 16.32 ± 0.62 Ma. This tuff allows the correlation of Section EET1 with Section ECA1 (Fig. 11) 3.5 km away. Conspicuous yellow beds also used for correlation are a package of about 10 m of fine-grained sediments assigned to FA1 that contains two or three layers that contrast in color with the remaining beds of the SCF (Fig. 10). These beds were used to correlate sections EET2, ECA2 and ECA1 (Fig. 11). Although present in Section ECA, the yellow layers are barely visible due to the presence of thick lenticular sandstone deposits that partly erode them (Figs. 10.1 and 11). Finally, due to the lack of guide levels, Section Point 9 was located in the correlation scheme according to its elevation above sea level (Fig. 11).

Size classes: macrofossils, mesofossils

Collected by Fernicola et al 2014 in 2013-2014

• Recent fieldwork carried out between 2013 and 2014 by joint expeditions of the MLP, MACN, and Duke University

Primary reference: M. Arnal, M. G. Vucetich, D. A. Croft, M. S. Bargo, J. C. Fernícola and S. F. Viscaino. 2017. Systematic revision and evolutionary history of Acarechimys Patterson in Kraglievich 1965 (Rodentia, Caviomorpha, Octodontoidea). Ameghiniana 54(3):307-330 [P. Mannion/M. Kouvari]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 210638: authorized by Philip Mannion, entered by Miranta Kouvari on 10.06.2020

Creative Commons license: CC BY (attribution)

Taxonomic list

 Astrapotheria - Astrapotheriidae
Astrapotherium sp.6 Burmeister 1879 placental
 Notoungulata - Hegetotheriidae
Hegetotherium mirabile6 Ameghino 1887 notoungulate
Pachyrukhos moyani6 Ameghino 1885 notoungulate
 Notoungulata - Interatheriidae
Protypotherium sp.6, "Protypotherium praerutilum" = Protypotherium praerutilum5, "Protypotherium attenuatum" = Protypotherium praerutilum6, Protypotherium australe6, Interatherium sp.6
Protypotherium sp.6 Ameghino 1882 notoungulate
"Protypotherium praerutilum" = Protypotherium praerutilum5 Ameghino 1887 notoungulate
MPM-PV 19642, MPM-PV 19639
"Protypotherium attenuatum" = Protypotherium praerutilum6 Ameghino 1887 notoungulate
Protypotherium australe6 Moreno 1882 notoungulate
Interatherium sp.6 Ameghino 1887 notoungulate
 Notoungulata - Homalodotheriidae
Homalodotherium sp.6 Huxley 1870 notoungulate
 Notoungulata - Toxodontidae
Adinotherium sp.6 Ameghino 1887 notoungulate
Adinotherium ovinum6 Owen 1846 notoungulate
Nesodon sp.6 Owen 1846 notoungulate
 Megatherioidea -
Schismotherium cf. fractum2 Ameghino 1887 edentate
 Megatherioidea - Megalonychidae
Hapalops cf. elongatus2 Ameghino 1891 edentate
 Megatherioidea - Megatheriidae
Planopinae indet.2 Ameghino 1887 edentate
 Megatherioidea - Nothrotheriidae
Xyophorus atlanticus2 Ameghino 1891 edentate
  - Mylodontidae
Nematherium longirostris2 Ameghino 1891 edentate
 Placentalia -
Rodentia indet.1 Bowdich 1821 rodent
 Rodentia -
Caviomorpha indet.1 caviomorph
Eocardia sp.1 Ameghino 1887 caviomorph
Eocardia montana1 Ameghino 1887 caviomorph
Eocardia excavata1 Ameghino 1891 caviomorph
“Eocardia” excavata
Neoreomys sp.1 Ameghino 1887 caviomorph
cf. Neoreomys sp.1 Ameghino 1887 caviomorph
Neoreomys australis1 Ameghino 1887 caviomorph
 Rodentia - Eocardiidae
Phanomys sp.1 Ameghino 1887 caviomorph
 Rodentia - Chinchillidae
Prolagostomus sp.1 Ameghino 1887 chinchilid
cf. Prolagostomus sp.1 Ameghino 1887 chinchilid
Prolagostomus pusillus1 Ameghino 1887 chinchilid
cf. Pliolagostomus sp.1 Ameghino 1887 chinchilid
Pliolagostomus sp.1 Ameghino 1887 chinchilid
Pliolagostomus notatus1 Ameghino 1887 chinchilid
 Rodentia -
Octodontoidea indet.1 Waterhouse 1839 caviomorph
Stichomys sp.1 Ameghino 1887 caviomorph
cf. Stichomys sp.1 Ameghino 1887 caviomorph
Stichomys/ Adelphomys
Stichomys regularis1 Ameghino 1887 caviomorph
 Rodentia - Acaremyidae
Acaremyidae indet.1 Wood 1949 caviomorph
Acaremys murinus1 Ameghino 1887 caviomorph
 Rodentia - Abrocomidae
"Acarechimys constans" = Ameghinomys constans
"Acarechimys constans" = Ameghinomys constans Ameghino 1887 chinchilla rat
MPM-PV 15091 MPM-PV 15092 MPM-PV 15093 MPM-PV 15094 MPM-PV 15095 MPM-PV 15096 MPM-PV 15097
 Rodentia -
Spaniomys sp.1 Ameghino 1877 caviomorph
Spaniomys riparius1 Ameghino 1887 caviomorph
Acarechimys sp.1 Patterson 1965 caviomorph
Acarechimys minutus1 Patterson and Pascual 1967 caviomorph
Acarechimys minutissimus Ameghino 1887 caviomorph
MPM-PV 15098 MPM-PV 15099 MPM-PV 15100 MPM-PV 15101 MPM-PV 15102 MPM-PV 17426 MPM-PV 17427
cf. Acarechimys minutissimus1 Ameghino 1887 caviomorph
Acarechimys gracilis Ameghino 1891 caviomorph
MPM-PV 17430 MPM-PV 17431 MPM-PV 17432 MPM-PV 17433 MPM-PV 17434
Prospaniomys "sp. nov.?"1 Ameghino 1902 caviomorph
MPM-PV 20560
 Rodentia - Octodontidae
Sciamys sp.1 Ameghino 1887 caviomorph
Sciamys latidens1 caviomorph
Sciamys principalis1 Ameghino 1887 caviomorph
 Rodentia -
Dudumus "sp. nov.?"1 Arnal et al. 2014 caviomorph
MPM-PV 20561
Chinchilloidea indet.1 Bennett 1833 caviomorph
 Rodentia - Neoepiblemidae
Perimys sp.1 Ameghino 1887 caviomorph
Perimys erutus1 Ameghino 1887 caviomorph
Perimys onustus1 Ameghino 1887 caviomorph
 Rodentia - Dinomyidae
Scleromys sp.1 Ameghino 1887 caviomorph
cf. Scleromys sp.1 Ameghino 1887 caviomorph
 Rodentia -
Steiromys sp.1 Ameghino 1887 caviomorph
Steiromys detentus1 Ameghino 1887 caviomorph
Steiromys duplicatus1 Ameghino 1887 caviomorph
 Panameriungulata - Proterotheriidae
Anisolophus floweri7 Ameghino 1887 placental
Diadiaphorus majusculus7 Ameghino 1887 placental
Thoatherium minusculum7 Ameghino 1887 placental
Tetramerorhinus lucarius7 Ameghino 1894 placental
Tetramerorhinus cingulatum7 Ameghino 1891 placental
 Panameriungulata - Macraucheniidae
Theosodon sp.7 Ameghino 1887 placental
 Sparassodonta -
Cladosictis patagonica3 Ameghino 1887 metatherian
Perathereutes pungens3 Ameghino 1891 metatherian
Sipalocyon gracilis3 Ameghino 1887 metatherian
 Sparassodonta - Borhyaenidae
Borhyaena tuberata3 Ameghino 1887 metatherian
 Microbiotheria - Microbiotheriidae
Microbiotherium tehuelchum3 Ameghino 1887 marsupial
 Paucituberculata - Abderitidae
Abderites meridionalis3 Ameghino 1887 marsupial
 Paucituberculata - Palaeothentidae
Acdestis oweni3 Ameghino 1887 marsupial
Palaeothentes lemoinei3 Ameghino 1887 marsupial
Palaeothentes intermedius3 Ameghino 1887 marsupial
Palaeothentes minutus3 Ameghino 1887 marsupial
 Gruiformes - Phorusrhacidae
Psilopterus sp.4 Moreno and Mercerat 1891 terror bird
MPM-PV 18902