PBDB Collection

Quebrada de los Jachaleros (Triassic of Argentina)

Where: La Rioja, Argentina (29.9° S, 68.2° W: paleocoordinates 39.0° S, 31.7° W)

• coordinate estimated from map

• local area-level geographic resolution

When: Coloradian other zone, Los Colorados Formation (Agua de la Peña Group), Norian (228.0 - 208.5 Ma)

• "upper levels" of the formation; formation is considered to be latest Triassic in age

•

•From Kent et al. 2014: The polarity pattern in this ∼600-m-thick red- bed section can be correlated to Chrons E7r to E15n of the Newark astrochronological polarity time scale. This represents a time in- terval from 227 to 213 Ma, indicating that the Los Colorados Formation is predominantly Norian in age, ending more than 11 My before the onset of the Jurassic.

• group of beds-level stratigraphic resolution

Environment/lithology: fluvial-lacustrine; red siliciclastic sediments

• "The sequence was interpreted as deposited by moderately sinuous fluvial systems, which laterally interfinger with and grade into horizontally bedded flood-plain deposits. To the top of the sequence, thin-bedded sandstones and siltstones dominate and were deposited in ponds and as crevasse splays in overbank settings" (Arcucci et al. 2004)

• "The red beds of Los Colorados Formation are composed by successive thinning-upward cycles characterized by coarse- to medium-grained sandstones and fine-grained sandstones intercalated with siltstones, which progressively dominate to the upper part of the unit (Fig. 2). Coarse-grained sandstone beds are generally tabular in geometry, cross stratified (large-scale trough and tabular cross-bedding) and locally display horizontal lamination. Rounded pebbles and cobbles of chert, quartzite and metamorphic rocks commonly mantle set boundaries. Massive and horizontal laminated siltstones interfinger with rippled lamination fine-grained sandstones forms the uppermost portion of the cycles" (Arcucci et al. 2004)

Size class: macrofossils

Collected by J. Bonaparte in 1966–1972

Collection methods: quarrying, mechanical,

Primary reference: J. F. Bonaparte. 1969. Dos nuevas "faunas" de reptiles triasicos de Argentina [Two new reptilian "faunas" of the Argentine Triassic]. Gondwana Stratigraphy (IUGS Symposium, Buenos Aires) 2:283-306 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 105691: authorized by Richard Butler, entered by Richard Butler on 23.02.2011, edited by Matthew Carrano and Grace Varnham

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names

Reptilia
Theropoda -	Theropoda indet.² Theropoda indet.² Marsh 1881 theropod PVL 3848, vertebrae and hindlimb material
Theropoda - Coelophysidae	Powellvenator podocitus n. gen. n. sp.⁵ Powellvenator podocitus n. gen. n. sp.⁵ Ezcurra 2017 coelophysoid PVL 4414-1 (Holotype, distal end of tibia and fibula, astragalus, calcaneum, distal tarsals 3 and 4, proximal ends of metatarsals II–IV, and most of metatarsal V from the right hindlimb) & referred specimens PVL 4414-3–5, 8.
Pseudosuchia - Ornithosuchidae	Riojasuchus tenuisceps n. gen. n. sp. Riojasuchus tenuisceps n. gen. n. sp. Bonaparte 1969 archosaur PVL 3827, skull and postcranial skeleton
Pseudosuchia - Stagonolepididae	Neoaetosauroides engaeus⁴ Neoaetosauroides engaeus⁴ Bonaparte 1969 aetosaur PULR 108, partial skull and postcrania
Loricata -	Crocodylomorpha "n. sp."⁶ Crocodylomorpha "n. sp."⁶ crocodilian PVL 3843, postcrania (previously assigned to Hemiprotosuchus leali)
Loricata - Protosuchidae	Hemiprotosuchus leali n. gen. n. sp.³ Hemiprotosuchus leali n. gen. n. sp.³ Bonaparte 1969 crocodilian PVL 3829 (holotype), skull and partial skeleton.
Loricata -	Pseudhesperosuchus jachaleri n. gen. n. sp.³ Pseudhesperosuchus jachaleri n. gen. n. sp.³ Bonaparte 1969 crocodilian PVL 3830. skull and postcranium
Osteichthyes
Therapsida -	Cynodontia indet.¹ Cynodontia indet.¹ cynodont PVL 3849, postcrania

¹Abdala and Ribeiro 2010; ²Arcucci et al. 2004; ³Bonaparte 1971; ⁴Desojo and Baez 2007; ⁵Ezcurra 2017; ⁶Leardi et al. 2020