El Guanaco (Miocene of Argentina)

Where: La Pampa, Argentina (37.7° S, 63.5° W: paleocoordinates 37.9° S, 61.8° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Cerro Azul Formation, Messinian (7.2 - 5.3 Ma)

• Schmidt et al. 2018: Figure 2 illustrates the stratigraphic distribution of the locality giving a general age estimate of 5.4-6.1Ma

•Prevosti et al. 2023: Biochronological methods were useful in ordering and estimating the age of the different faunas of the Cerro Azul Formation, ranging from ca. 8 to ca. 5.7 Ma. Some appear to be transitional between Chasicoan and “Huayquerian” faunas (Cerro La Bota, Cerro Patagua, and Algarrobo del Águila), and other three (Barrancas Coloradas, El Guanaco, and Caleufú) cover the latest Miocene, even some of them could have reached the earliest Pliocene.

• formation-level stratigraphic resolution

Environment/lithology: loess; lithified, brown siltstone

• Deposits at Telen, Bajo Giuliani, El Guanaco and Caleufú were interpreted as loess-like deposits with immature palaeosols and little diagenetic alteration (Montalvo et al., 2008, 2016; Verzi et al., 2008).

Size class: macrofossils

Reposited in the MLP

Primary reference: F. J. Goin and C. Montalvo. 1988. Revisión sistemática y reconocimiento de una nueva especie del género Thylatheridium Reig (Marsupialia, Didelphidae). Ameghiniana 25(2):161-167 [C. Jaramillo/J. Carrillo]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 140932: authorized by Carlos Jaramillo, entered by Juan Carrillo on 19.03.2013, edited by Kateryn Pino, Grace Varnham and Miranta Kouvari

Creative Commons license: CC BY (attribution)

Taxonomic list

 Didelphimorphia - Didelphidae
Hyperdidelphys pattersoni2 Reig 1952 opossum
Thylatheridium dolgopolae Reig 1952 opossum
 Polydolopimorphia - Argyrolagidae
"Microtragulus rusconii" = Argyrolagus rusconii2
"Microtragulus rusconii" = Argyrolagus rusconii2 Goin et al. 2000 metatherian
 Sparassodonta - Proborhyaenidae
"Thylacosmilus atrox" = Thylacosmilus atrox4, "Achlysictis cf. lelongi" = Thylacosmilus atrox2
"Thylacosmilus atrox" = Thylacosmilus atrox4 Riggs 1933 metatherian
"Achlysictis cf. lelongi" = Thylacosmilus atrox2 Riggs 1933 metatherian
 Theriamorpha - Dasypodidae
Chorobates villosissimus7 Reig 1958 armadillo
Chorobates cf. villosissimus7 Reig 1958 armadillo
Doellotatus inornatus7 Rovereto 1914 armadillo
Chasicotatus ameghinoi7 Scillato-Yané 1977 armadillo
 Notoungulata - Hegetotheriidae
Paedotherium minor6 Cabrera 1937 notoungulate
 Rodentia - Cricetidae
Sigmodontinae indet.4 Wagner 1843 mouse
 Rodentia - Chinchillidae
Lagostomus telenkechanum3 Rasia and Candela 2017 viscacha
GHUNLPam 131 right mandible with i and p4-3, left with m3, and isolated I, GHUNLPam 22657 palate with left P4-M3 and right broken P4-M2.
Lagostomus pretrichodactyla3 Rovereto 1914 viscacha
GHUNLPam 12958 right mandible with p4-m3, GHUNLPam 14854 palate with left P4-M2 and right M1-3.
 Panameriungulata - Proterotheriidae
Eoauchenia primitiva5 Ameghino 1887 placental
 Tinamiformes - Tinamidae
Nothura sp.1 Wagler 1827 tinamou
GHUNLPam 14861/1, distal portion of left tibiotarsus
"Xenodontomys simpsoni" = Proctenomys simpsoni8
"Xenodontomys simpsoni" = Proctenomys simpsoni8 Kraglievich 1961
GHUNLPam 342 (see also ref 65013)