Where: Chubut, Argentina (42.6° S, 70.3° W: paleocoordinates 42.9° S, 67.7° W)
• coordinate stated in text
• small collection-level geographic resolution
When: Collón Curá Formation, Tortonian (11.6 - 7.2 Ma)
• Brandoni et al. 2017: The new specimen presented here as ‘Xyophorus’ sp. (LIEB PV 5129) has a DL/TRL index of ca. 14, this value being larger than the index for ‘X.’ villarroeli (12.07) from the Mauri Formation (ca. 10.3 Ma), but smaller than the value for ‘X.’ bondesioi (16.45) from Arroyo Chasicó Formation (ca. 10–8.7 Ma) (Table 1, Figure 6). Following the relationship between DL/TRL index and age proposed by Brandoni (2014), where the value of the index would decrease with the age of the bearing sediments, the DL/TRL index of ca. 14 for ‘Xyophorus’ sp. (LIEB PV 5129) would suggest a Tortonian age (11.63–7.24 Ma) for the deposits of Collón Curá Formation at Cerro Zeballos (Figure 6), which results in a ‘younger age’ compared to the middle Miocene age traditionally accepted for the Collón Curá Formation with the Colloncuran fauna sensu stricto. Although no absolute ages for Cerro Zeballos are available yet, the geographic proximity of Cerro Zeballos to Cushamen River (with levels dated in ca. 11.2 Ma) supports the possibility that the sediments yielding specimen LIEB PV 5129 are younger than those from those associated to the ignimbrite that carry the Colloncuran fauna sensu stricto, so the tenta- tive Tortonian age (late Miocene) indicated by the presence of ‘Xyophorus’ sp (LIEB PV 5129).
•Brandoni et al. 2019: there are no absolute dates for Cerro Zeballos, the chronological location of this locality in Fig. 6a is relative and based on the study of Brandoni et al. (2017) that indicated an early Tortonian age (its position could change if absolute dates appear).
•Vera, 2019: he Collón Curá Formation (Roth, 1899; Yrigoyen, 1969) is widely distributed in western Patagonia, from Neuquén Province (e.g., Estancia Collón Curá, Cañadón del Tordillo) in the North, to Río Negro (e.g., Comallo, Estancia El Criado) and Chubut (e.g., Río Chico, Cerro Zeballos) provinces in the South, ranging in age from approximately 16 Ma to 11 Ma (Burdigalian–Tortonian; Marshall et al., 1977; Mazzoni and Benvenuto, 1990; Bilmes et al., 2013; Ramos et al., 2015; Brandoni et al., 2017).
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•Vera, et al. 2018: Several absolute ages for the Coll?on Cur?a Formation indicate that this unit ranges from approximately 16Ma Miocene; Marshall et al. 1977; Mazzoni & Benvenuto to 11Ma (Burdigalian?Tortonian; early to late 1990; Bilmes et al. 2013;Ramos et al. 2015). Unfortunately, there is no absolute age for the Coll?on Cur?a Formation at Cerro Zeballos, but some of the recovered mammal taxa differ from the typical Colloncuran (Martin & Tejedor 2007; Gonz?alez Ruiz et al. 2011; Martin et al. 2016)and suggest a Tortonian age (late Miocene; Brandoni et al. 2017 and references cited therein)
Environment/lithology: alluvial fan; lithified, tabular, concretionary, tuffaceous, yellow sandstone and lithified limestone
•Brandoni et al. 2017: According to Bilmes et al. (2014) the Collón Curá Formation, near this area, is the result of the conformation of isolated depocenters in which ephemeral and deep lacustrine systems were developed. The described section has no structures that could indicate the deposition agent, although the tuffaceous material and the presence of roots suggests a shallow and low energy system of lagoons or lakes, and a floodplain with shallow and low energy fluvial courses, probably with periods of aerial exposure.
•Brandoni et al. 2017: The described profile (Figure 2) starts with a section of ca. 15 m of massive ocher or yellowish white tuffaceous sandstone, in general very friable and powdery, forming the typical badlands landscape. In all the profile, levels with concentrations of reddish concretions composed by tuffitic material frequently appears (Tf in Figure 2), and because they are more resistant to weathering they form steps in the profile. These levels with concretions and the presence of roots could indicate pedogenic processes. In all the section fossil vertebrates are abundant, even inside these con- cretions. Specimen LIEB PV 5129 was collected in the middle of this 15 m section. The profile continues, in paracomformity, with ca. 3 m of greenish tuffaceous mudstone with intercalated levels of ocher tuffaceous fine sandstones with massive structures (T in Figure 2). Above this, the profile continues with epiclastic deposits of claystone, mudstone, and grainstones, with some pyroclastic subordinated levels intercalated.
Size class: macrofossils
Collected by Brandoni et al. in 2019
• Brandoni et al. 2019: LEIB-PV 6153 (a complete right astragalus) is housed in Laboratorio de Investigaciones en Evolución y Biodiversidad (PV, Paleovertebrados), Esquel, Argentina.
•Brandoni et al. 2017: LIEB PV 5129 is housed in Laboratorio de Investigaciones en Evolución y Biodiversidad (-PV, Paleovertebrados), Esquel, Argentina.
•Vera, 2019: The fossil specimens described below were recovered by the CIEMEP paleontology team during several field seasons (2003–2018) to Cerro Zeballos (Chubut Province; Fig. 1) and they are sheltered in the vertebrate paleontology collection of the Laboratorio de Investigaciones en Evolución y Biodiversidad (LIEB), Esquel, Chubut, Argentina.
Primary reference: D. Brandoni, L. González Ruiz, A. Reato and G. Martin. 2017. Chronological implications of the nothrotheriid ‘Xyophorus’ (Mammalia, Xenarthra) from the Collón Curá Formation (Miocene of Patagonia, Argentina). Historical Biology [P. Mannion/G. Varnham/G. Varnham]more details
Purpose of describing collection: taxonomic analysis
PaleoDB collection 201907: authorized by Philip Mannion, entered by Grace Varnham on 09.06.2019, edited by Miranta Kouvari
Creative Commons license: CC BY (attribution)
Taxonomic list
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"Protypotherium cf. endiadys" = Protypotherium praerutilum4
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Hemihegetotherium tantillum n. sp.3
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