Also known as CY3
Where: Río Negro, Argentina (41.4° S, 69.6° W)
• Paleocoordinates: 41.8° S, 61.6° W (Wright 2013)
• coordinate stated in text
• small collection-level geographic resolution
When: Lower Member (Las Chacras Formation), Bartonian to Bartonian (41.0 - 33.9 Ma)
• The proposed stratigraphic correlations and geochronological dates of the Las Chacras Formation indicate that the stratigraphic interval bearing the Lower Las Chacras fauna is younger than the maximum age estimated for the lower basalt flow exposed at Cerro Yeso (44 Ma.) The strong similarity with the Mustersan assemblage from the Rosado Member at Gran Barranca South of Colhué Huapi Lake, with a well constrained age of 38.16 – 37.4 Ma. (Dunn et al., 2013), suggests that the Lower Las Chacras Formation and its fauna is more likely of late Bartonian or early Priabonian age. Fossils occurs 22 m from the base of the formation in the measured section
• bed-level stratigraphic resolution
Environment/lithology: "floodplain"; massive, volcaniclastic, gray, green mudstone
Size class: macrofossils
Collection methods: This is the site where Casamiquela collected all his fossils (according to Mr. Marileo, a local farmer who accompanied Casamiquela in his prospections). Further collection by Kramarz et al. 2022 in October 2017 and April 2018.
Primary reference: A. Kramarz, E. Bellosi, M. Bond, A. M. Forasiepi, J. C. Fernicola, G. Aguirrezabala, and D. T. Rezende. 2022. Eocene mammals from volcaniclastic deposits of the Somun Cura Plateau: biostratigraphic implications for north Patagonia Paleogene. Andean Geology 49(2) [P. Mannion/G. Varnham/P. Mannion]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 225622: authorized by Philip Mannion, entered by Grace Varnham on 20.05.2022
Creative Commons license: CC0 (CC0)
Taxonomic list
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Pichipilidae "n. gen." Marshall 1980 marsupial MJHG-NCP 277, fragment of left dentary with ?m2; MJHG-NCP 278, left mandibular fragment with four alveoli, ?p3, and alveolus for root of ?m1
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Interatheriidae indet. Ameghino 1887 notoungulate MJHG-NCP 28, right maxillary fragment with C1-P1 and roots for P2; MJHG-NCP 276, isolated right c1?
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Puelia sigma Ameghino 1901 notoungulate MJHG-NCP 25, right mandibular fragment with partial m1-m3; MJHG-NCP 27, right mandibular fragment with p3-p4 and associated incisor and fragments
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"Isutaetus depictus" = Pseudeutatus depictus
"Isutaetus depictus" = Pseudeutatus depictus Ameghino 1902 armadillo MJHG-NCP 24, six probably associated osteoderms (five fixed and one movable); MJHG-NCP 26, three fixed probably associated osteoderms; MJHG-NCP 274, four probably associated isolated osteoderms (three fixed and one fragment movable), and a fragment of one movable osteoderm; MJHG-NCP 274, four probably associated isolated osteoderms (three fixed and one fragment movable), and a fragment of one movable osteoderm
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