Also known as CH2
Where: Río Negro, Argentina (41.4° S, 69.7° W: paleocoordinates 43.6° S, 60.7° W)
• coordinate stated in text
• small collection-level geographic resolution
When: Lower Member (Las Chacras Formation), Bartonian to Bartonian (41.3 - 33.9 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 come from 45 m above the base and 3 m below the major pyroclastic flow of the upper half of the measured section.
• bed-level stratigraphic resolution
Environment/lithology: fluvial; conglomerate
Size class: macrofossils
Collection methods: Collected by Rodolfo Casamiquela during 1940’s and 1950’s. 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 225623: authorized by Philip Mannion, entered by Grace Varnham on 20.05.2022
Creative Commons license: CC BY (attribution)
Taxonomic list
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cf. Astraponotus sp. Ameghino 1901 placental MJHG-NCP 269, probably associated upper and lower premolar
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Pseudhyrax eutrachytheroides Ameghino 1901 notoungulate MJHG-NCP 4, two isolated upper premolars; MJHG-NCP 7, isolated right m3; MJHG-NCP 8, left maxillary fragment with P4-M1; MJHG-NCP 9, left mandibular fragment with p2; MJHG-NCP 255, probably associated left p3 or p4, and m1-m3; MJHG-NCP 258, right mandibular fragment with very worn p2-p4; MJHG-NCP 259, probably associated right p2-p4, m3, and left p1?; MJHG-NCP 260, right maxillary fragment with M1 or M2; MJHG-NCP 263, left premaxillary fragment with two incisors, left maxillary fragment with P1, two isolated upper molars, and one lower molar, and fragments (not associated); MJHG-NCP 271, right mandibular fragment with m1 and partial m2
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Puelia sigma Ameghino 1901 notoungulate MJHG-NCP 2, associated left maxillary fragment with roots of P4, complete P3, M1-M3, right maxillary fragment with P1-P3, and three upper anterior teeth (I1, I2, and I3 or C1); MJHG-NCP 5, right mandibular fragment with m2-m3
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? Periphragnis circunflexus Ameghino 1901 notoungulate MJHG-NCP 252, four associated lower cheek teeth, probably p3, p4, m1 and partial m2, one incisor-like lower tooth, a partial upper molar, and associated cranial and mandibular fragments
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"Isutaetus depictus" = Pseudeutatus depictus
"Isutaetus depictus" = Pseudeutatus depictus Ameghino 1902 armadillo MJHG-NCP 261, one isolated osteoderm
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