Anfiteatro (Miocene of Argentina)

Where: Santa Cruz, Argentina (51.1° S, 69.1° W: paleocoordinates 51.7° S, 63.4° W)

• coordinate stated in text

• outcrop-level geographic resolution

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

• The new localities come from the lowest part of the

•Santa Cruz Formation exposed on the Atlantic coast

• group of beds-level stratigraphic resolution

Environment/lithology: terrestrial; tuffaceous, silty claystone

• The fossil bed is a water-deposited tuffaceous silty clay.

•The bed varies in thickness up to a maximum of 2 m. When dry, its weathered surfaces are grayish-white to tan, but it is greenish-white in the unweathered state. Deposition must have been rapid, as a number of fossils were observed to extend up to 20 cm into the rock. Neither cross-bedding nor root casts are visible; the fossils lack obvious surface weathering at the time of deposition and often are found in a partially articulated state. It appears that this tuffa- ceous horizon was buried soon after deposition and before a paleosol could be established.

Size classes: macrofossils, mesofossils

Reposited in the MLP

Primary reference: R. F. Kay, S.F. Vizcaino, M. S. Bargo, J. M. G. Perry, F. J. Prevosti and J. C. Fernicola. 2008. Two new fossil vertebrate localities in the Santa Cruz Formation (late early – early middle Miocene, Argentina), ~ 51° South latitude. Journal of South American Earth Sciences 25:187-195 [P. Mannion/M. Kouvari]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 176578: authorized by Jelle Zijlstra, entered by Jelle Zijlstra on 17.02.2016, edited by Miranta Kouvari

Creative Commons license: CC BY (attribution)

Taxonomic list

 Sparassodonta - Borhyaenidae
Borhyaena tuberata5 Ameghino 1887 metatherian
MPM-PV 4324
 Sparassodonta - Hathlyacynidae
"Hathlyacynidae indet." = Hathlyacininae
"Hathlyacynidae indet." = Hathlyacininae Ameghino 1894 metatherian
small species
 Sparassodonta -
Cladosictis patagonica5 Ameghino 1887 metatherian
MPM-PV 3645, 4326, 4325, 4327, 4329
 Paucituberculata - Palaeothentidae
"Acdestis owenii" = Acdestis oweni4
"Acdestis owenii" = Acdestis oweni4 Ameghino 1887 marsupial
 Primates - Homunculidae
cf. Homunculus sp. Ameghino 1891 monkey
 Rodentia -
Neoreomys sp. Ameghino 1887 caviomorph
Neoreomys australis1 Ameghino 1887 caviomorph
MPM-PV 3513, skull, atlas, axis, proximal femur; 3515, skull and dentary; 3516, partial femur; 3517, dentary, astragalus, calcaneum; 3518, rostrum, pelvis, femur fragments and tibia; 3519, skull, dentaries, postcrania; 3520, dentary and humerus; 3521, skull fragment, postcrania; 3522, skull and femur; 3523, skull and proximal femur
Eocardia sp. Ameghino 1887 caviomorph
 Rodentia - Octodontidae
Sciamys sp.4 Ameghino 1887 caviomorph
 Rodentia -
Spaniomys modestus Ameghino 1887 caviomorph
 Panameriungulata - Proterotheriidae
"Diadiaphorus sp." = Proterotherium
"Diadiaphorus sp." = Proterotherium Ameghino 1883 placental
 Notoungulata - Hegetotheriidae
Hegetotherium sp. Ameghino 1887 notoungulate
 Notoungulata - Interatheriidae
Interatherium sp., "Interatherium robustum" = Interatherium extensus2
Interatherium sp. Ameghino 1887 notoungulate
"Interatherium robustum" = Interatherium extensus2 Fernández et al. 2023 notoungulate
MPM-PV 3471, cranium, mandible, humerus; 3527, cranium, mandible, humerus, ulna, femur, tibia; 3528, mandible; 3539, tibia
 Notoungulata - Toxodontidae
Adinotherium sp. Ameghino 1887 notoungulate
Adinotherium ovinum2 Owen 1846 notoungulate
MPM-PV 3542, humerus, ulna, tibia
Nesodon sp. Owen 1846 notoungulate
Nesodon imbricatus Owen 1846 notoungulate
 Astrapotheria - Astrapotheriidae
Astrapotherium sp. Burmeister 1879 placental
Astrapotherium magnum4 Owen 1853 placental
 Cingulata - Peltephilidae
Peltephilus pumilus6 Ameghino 1887 edentate
MPM-PV 3433, skull and postcrania; MPM-PV 3643, skull and mandible
Peltephilus cf. pumilus Ameghino 1887 edentate
 Cingulata - Chlamyphoridae
Proeutatus sp., "Proeutatus oenophorus" = Proeutatus oenophorum6
Proeutatus sp. Ameghino 1891 edentate
"Proeutatus oenophorus" = Proeutatus oenophorum6 Ameghino 1887 edentate
MPM-PV 3435, osteoderms
 Cingulata - Propalaehoplophoridae
Propalaehoplophorus sp. Ameghino 1887 edentate
Cochlops muricatus6 Ameghino 1889 edentate
MPM-PV 3432, skull, carapace fragment
Aves indet. Linnaeus 1758 bird
 Gruiformes - Phorusrhacidae
Psilopterus lemoinei3 Moreno and Mercerat 1891 terror bird
MPM-PV 4240, left tibiotarsus