Arroyo Chasicó (Miocene of Argentina)

Where: Buenos Aires, Argentina (38.6° S, 63.0° W: paleocoordinates 38.8° S, 60.1° W)

• coordinate estimated from map

• local area-level geographic resolution

When: Arroyo Chasicó Formation, Chasicoan (10.0 - 9.0 Ma)

• A recent interpretation of radiometric and paleomagnetic data of the ACF supports an age between at least 9.43 and 8.7 Ma (Zarate et al., 2007).

• formation-level stratigraphic resolution

Environment/lithology: "floodplain"; sandstone

• The beginning of Chasicoan sedimentation was placed after the general withdrawal of the mid-Miocene transgression (Pascual et al., 1996). According to Ramos (1999b), the transgression extended across most of eastern South America, covering the Pampas, Chaco region, and Patagonia up to the Andean foothill and reaching areas near the central and northern Andes of Argentina. The regional regression that followed was thought to be synchronous with the 10.5 Ma global sea level fall cited by Haq et al. (1987) (see Verzi, 1999, Pascual et al., 1996).
• an extensive plateau capped by a thick calcrete crust, which in turn is covered by a thin apron of late Pleistocene–Holocene eolian deposits.

Size class: macrofossils

Preservation: permineralized

Collection methods: Gonzalez-Ruiz, et al. 2012: their Material was collected during a field trip organized by the Facultad de Ciencias Naturales y Museo de La Plata (Argentina) and Duke University (USA).

•Cerdeno 2000: material from the Museo "J. C. Moyana" de Mendoza. Recolección efectuadas por J.R. Contreras, Mones-Aivarado y Ripa-Alvara- do entre 1967 y 1969, según figura en las etiqueta encontradas junto a los fósiles.

Primary reference: M. A. Zárate, P. H. Schultz, A. Blasi, C. Heil, J. King and W. Hames. 2007. Geology and geochronology of type Chasicoan (late Miocene) mammal-bearing deposits of Buenos Aires (Argentina). Journal of South American Earth Sciences 23:81-90 [D. Croft/D. Croft]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 79180: authorized by Darin Croft, entered by Darin Croft on 27.02.2008, edited by Bettina Kaphingst, Juan Carrillo, Jelle Zijlstra, Miranta Kouvari, Grace Varnham, Evangelos Vlachos and Kateryn Pino

Creative Commons license: CC BY (attribution)

Taxonomic list

• Rasia & Canela 2017: Arroyo Chasico area, southwest of Buenos Aires Province, Argentina, MLP-Pv 55-IV- 28-43 and MLP-Pv 55-IV-28-44 come from in front of Rado- vitzki farm; MLP-Pv 55-IV-28-42 comes from in front of Torres and Stefanazzi farms; MLP-Pv 60-VI-18-101 comes from the left margin of Stefanazzi farm; MLP-Pv 76-VI-12-47 comes from the left bank of Arroyo Chasic?o, 400 m upstream from Bajada de los Toros; MLP-Pv 60-VI-18-100, MLP-Pv 60-VI-18-107, MLP-Pv 92-XI-19-1, and MLP-Pv 92-XI-19-2 come from the Arroyo Chasic?o area, without more precise geographic provenance.
Amphibia
 Salientia -
Anura indet.1 frog
leg bone
Aves
 Gruiformes - Phorusrhacidae
Psilopterus colzecus1 Tonni and Tambussi 1988 terror bird
Reptilia
 Squamata -
"Carlesia cf. pendolai" = Dicarlesia1
"Carlesia cf. pendolai" = Dicarlesia1 lizard
one partial skeleton
 Testudines - Testudinidae
Testudinidae indet.7 Batsch 1788 turtle
osteoderms
Mammalia
 Cingulata -
Palaehoplophorini "1"1 Hoffstetter 1958 edentate
four osteoderms
Palaehoplophorini "2"1 Hoffstetter 1958 edentate
ten osteoderms
Palaehoplophorini "3"1 Hoffstetter 1958 edentate
five osteoderms
Palaehoplophorini "4"1 Hoffstetter 1958 edentate
two osteoderms
Palaehoplophorini "5"1 Hoffstetter 1958 edentate
one osteoderm
Palaehoplophorini "6"1 Hoffstetter 1958 edentate
one osteoderm
Palaehoplophorini "7"1 Hoffstetter 1958 edentate
one osteoderm
? Palaehoplophorini "8"1 Hoffstetter 1958 edentate
four osteoderms
Palaehoplophorini "9"1 Hoffstetter 1958 edentate
one osteoderm
 Cingulata - Pampatheriidae
Kraglievichia sp.15 Castellanos 1927 edentate
two osteoderms. M.L.P.: 55-N-28-84; 60-VI-18-68; CH lla(l). M.M'.P.: 265-M; ' 358-M (ref 27152 also)
 Cingulata - Glyptodontidae
"Sclerocalyptini "1"" = Hoplophorini1, "? Sclerocalyptini "2"" = Hoplophorini1, Plohophorini "1"1, Plohophorini "2"1
"Sclerocalyptini "1"" = Hoplophorini1 Huxley 1864 glyptodon
one osteoderm
"? Sclerocalyptini "2"" = Hoplophorini1 Huxley 1864 glyptodon
one osteoderm
Plohophorini "1"1 Castellanos 1932 glyptodon
one osteoderm and two osteoderms from the tail
Plohophorini "2"1 Castellanos 1932 glyptodon
one osteoderm from the tail
 Cingulata - Peltephilidae
Epipeltephilus kanti n. sp.9 Gonzalez-Ruiz et al. 2012 edentate
Holotype: MLP 92-XI-19-7 and others. The type comes from the lower part of the Vivero member
 Cingulata - Dasypodidae
Vetelia perforata n. sp.15 Scillato-Yané 1977 armadillo
seven specimens. Holotype: MLP 28-X-11-45 (also ref 27152)
Chasicotatus ameghinoi n. gen. n. sp.15 Scillato-Yané 1977 armadillo
eight specimens. Holotype: MLP CH 10 (also ref 27152)
Proeuphractus sp.15 Ameghino 1886 armadillo
four specimens. M.L.P.: 28-X-1l-62; 28-X-11-67; 55-N-28-81a; 55-N-28-87a; 60-VI-18-77; 60-VI-18-78; CH 19; CH 35a; CH 36. M.M.P.: 264-M; 285-S. Also ref 71054: MCNAM-PV 3226, 7
Peltephilinae indet.15 Lydekker 1894 armadillo
MLP 28-X-11-88
 Megatherioidea - Megatheriidae
Plesiomegatherium halmyronomum n. sp.4 Cabrera 1928 edentate
the type. barranca derecha del arroyo chasico. cerca de la laguna del mismo nombre
Anisodontherium halmyronomum n. gen.3 Cabrera 1928 edentate
Holotype: MLP 26-IV-10-1
 Megatherioidea - Megalonychidae
Protomegalonyx chasicoensis2 Scillato-Yané 1977 edentate
femur MMP M 478
 Notoungulata - Mesotheriidae
Typotheriopsis sp.1 Cabrera and Kraglievich 1930 notoungulate
nine specimens
Typotheriopsis chasicoensis6 Cabrera and Kraglievich 1931 notoungulate
MCNAM-PV 3211 - 5
 Notoungulata - Interatheriidae
Protypotherium distinctum5 Cabrera and Kraglievich 1931 notoungulate
Holotype: MLP 12-2178, right maxilla
 Notoungulata - Hegetotheriidae
Hegetotheriinae indet.1 notoungulate
six specimens
Hemihegetotherium torresi6 Cabrera and Kraglievich 1931 notoungulate
MCNAM-PV 3216
Paedotherium minor1 Cabrera 1937 notoungulate
many specimens (30). Also ref. 71054: MCNAM-PV 3217 - 20
 Notoungulata - Toxodontidae
Pisanodon nazari1 Cabrera and Kraglievich 1931 notoungulate
two specimens
 Notoungulata - Homalodotheriidae
Chasicotherium rothi n. gen. n. sp.8
Chasicotherium rothi n. gen. n. sp.8 Cabrera and Kraglievich 1931 notoungulate
The taxon is named in Cabrera and Kraglievich (1931; not seen). de Ringuelet adds more material. MLP 26-XI-20-1 (type)
 Panameriungulata - Macraucheniidae
Cullinia levis14 Cabrera and Kraglievich 1931 placental
 Panameriungulata - Proterotheriidae
Proterotheriinae indet.1 Ameghino 1885 placental
partial limb bone
Neobrachytherium ullumense14 Soria 2001 placental
Brachytherium sp.6 Ameghino 1883 placental
MCNAM-PV 3222 - 25
 Rodentia - Chinchillidae
Lagostominae indet.1 Wiegmann 1832 chinchilid
three craniodental specimens
Lagostomus telenkechanum n. sp.13 Rasia and Candela 2017 viscacha
Holotype MLP-Pv 60-VI-18-100 and other specimens
 Rodentia - Dinomyidae
? Tetrastylus sp.1 Ameghino 1886 caviomorph
a tooth
 Rodentia - Caviidae
? Parodimys sp.1 Kraglievich 1932 caviomorph
mandible
Orthomyctera sp.1 Ameghino 1889 caviomorph
three specimens
Cardiomys sp.1 Ameghino 1885 caviomorph
two craniodental specimens
Cardiomys leufuensis n. sp.12 Pérez et al. 2018 caviomorph
MLP 55-IV-28-11 (type). Also, specimen MLP 29-IX-3-19 (semi-complete post cranial ref 70039)
Procardiomys martinoi11 Pascual 1961 caviomorph
 Rodentia - Hydrochoeridae
"Procardiatherium sp." = Cardiatherium1, Cardiatheriinae indet.1
"Procardiatherium sp." = Cardiatherium1 Ameghino 1883 caviomorph
three teeth
Cardiatheriinae indet.1 Kraglievich 1930 caviomorph
one tooth
 Sparassodonta -
Chasicostylus castroi n. gen. n. sp.10
Chasicostylus castroi n. gen. n. sp.10 Reig 1957 metatherian
MLP 57-XI-9-2, maxilla and dentary, holotype; MLP 55-IV-28-59, right dentary with base of c and alveoli of p1-3, tentatively referred
 Sparassodonta - Borhyaenidae
Pseudolycopsis cabrerai1 Marshall 1976 metatherian
maxilla with three teeth