Chañares Tetrapod Assemblage (Triassic of Argentina)

Also known as ETE Locality 1586, Los Chañares

Where: La Rioja, Argentina (29.9° S, 67.8° W: paleocoordinates 49.9° S, 37.7° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Chañares Formation (Agua de la Peña Group), Ladinian (242.0 - 237.0 Ma)

• formation-level stratigraphic resolution

Environment/lithology: fluvial-lacustrine; poorly lithified, concretionary, tuffaceous, volcaniclastic, blue, calcareous claystone

• Active rift basin with volcanic avtivity. Alluvial setting with evidence for small rivers and lakes. [ETE sed env 1: fluv_lacustr, ETE sed env 2: floodplain ETE event: airfall, ETE env comment: crev splay]
• Nodular and massive blue-gray clay-rich strat. Volcaniclastic and calcareous. Relic glass shards (replaced by clacite) set in a groundmass of microcrystalline silica and clay. Brown oblate carbonate concretions yield fossils. [ETE rock type adj: blueish tinge, ETE lithology comments: 0]

Size class: macrofossils

Preservation: concretion, original phosphate

Reposited in the MCZ, MLP

Collection methods: surface (float), surface (in situ), mechanical,

• [ETE Size: .; ETE reference list: 802, 768, 816, 781, 841, 812, 673, 793, 786, 772, 794, 801, 887, 886, 884, 881, 885, 882, 883, 880, 879, 878, 851, 849, 888, 848, 677, 680, 892, 683, 837, 834, 831, 833, 832, 680, 706, 678, 738, 712, 850, 811, 810, 679, 677, 737, 708, 739, 743, 740, 746, 710, 749, 750, 713, 716, 756, 760, 763, 726, 893, 759, 836, 835, 824, 687, 825, 826, 724, 807, 711, 747, 767, 779, 688, 751, 735, 739, 732, 736, 720, 727, 748, 850, 797, 795, 798, 782, 734, 809, ; ETE museum list:]

Primary reference: R. R. Rogers, A. B. Arcucci, F. Abdala, P. C. Sereno, C. A. Forster and C. L. May. 2001. Paleoenvironment and taphonomy of the Chanares Formation tetrapod assemblage (Middle Triassic), northwestern Argentina: spectacular preservation in volcanogenic concretions. Palaios 16:461-481 [R. Rogers/R. Rogers/R. Rogers]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 26092: authorized by Ray Rogers, entered by Ray Rogers on 03.10.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Reptilia
 Diapsida - Doswelliidae
Tarjadia ruthae Arcucci and Marsicano 1999 archosauromorph
 Diapsida - Proterochampsidae
Gualosuchus reigi Romer 1971 archosauromorph
Chanaresuchus bonapartei Romer 1971 archosauromorph
Tropidosuchus romeri Arcucci 1990 archosauromorph
 Dinosauromorpha - Silesauridae
"Pseudolagosuchus major" = Lewisuchus admixtus
"Pseudolagosuchus major" = Lewisuchus admixtus Romer 1972 ornithodiran
 Dinosauromorpha -
Marasuchus lilloensis Romer 1972 ornithodiran
 Lagerpetidae - Lagerpetidae
Lagerpeton chanarensis Romer 1971 ornithodiran
presumably includes PVL 4619, 4625, and 5000, which do not have "precise locality information" (Sereno and Arcucci 1993)
 Pseudosuchia - Gracilisuchidae
Gracilisuchus stipanicicorum Romer 1972 archosaur
 Loricata - Rauisuchidae
Luperosuchus fractus Romer 1971 rauisuchid
Osteichthyes
 Dicynodontia - Stahleckeriidae
"Dinodontosaurus platygnathus" = Jachaleria platygnathus, Dinodontosaurus platiceps, "Dinodontosaurus brevirostris" = Dinodontosaurus pedroanum
"Dinodontosaurus platygnathus" = Jachaleria platygnathus Cox 1968 dicynodont
"Dinodontosaurus brevirostris" = Dinodontosaurus pedroanum Tupi-Caldas 1936 dicynodont
 Therapsida -
Probainognathus jenseni Romer 1970 cynodont
 Therapsida - Chiniquodontidae
"Probelesodon lewisi" = Chiniquodon theotonicus
"Probelesodon lewisi" = Chiniquodon theotonicus Huene 1936 cynodont
 Therapsida - Traversodontidae
Massetognathus pascuali Romer 1967 cynodont
most abundant taxon