[D] Pampadromaeus barberenai [Su] [sG] [T]
Describer
Cabreira, Schultz, Bittencourt, Soares, Fortier, Silva & Langer 2011
Time
Triassic Late Carnian
Classification
Saurischia Sauropodomorpha [Eusaurischia ]
Diet
Herbivore?
Fossilsite
Santa Maria Formation (Rosário do Sul Group) Alemoa Member, \\\\\\\"Janner\\\\\\\" (also known as \\\\\\\"Várzea do Agudo\\\\\\\") locality, geopark of Paleorrota, southern Brazil
Info
Abstract Post-Triassic theropod, sauropodomorph, and ornithischian dinosaurs are readily recognized based on the set of traits that typically characterize each of these groups. On the contrary, most of the early members of those lineages lack such specializations, but share a range of generalized traits also seen in more basal dinosauromorphs.
Here, we report on a new Late Triassic dinosaur from the Santa Maria Formation of Rio Grande do Sul, southern Brazil. The specimen comprises the disarticulated partial skeleton of a single individual, including most of the skull bones. Based on four phylogenetic analyses, the new dinosaur fits consistently on the sauropodomorph stem, but lacks several typical features of sauropodomorphs, showing dinosaur plesiomorphies together with some neotheropod traits.
This is not an exception among basal dinosaurs, the early radiation of which is characterized by a mosaic pattern of character acquisition, resulting in the uncertain phylogenetic placement of various early members of the group.
Etymology
The generic name is derived from the Quechua word pampa (=plain), in reference to the grassland landscape that covers parts of Rio Grande do Sul, and dromaeus, variant of Greek δρομεύς (=runner), in reference to the probable cursoriality of the animal. The specific epithet honors the Brazilian palaeontologist Mário C. Barberena.
Holotype
ULBRA-PVT016 (Museu de Ciências Naturais, Universidade Luterana do Brasil, Canoas), disarticulated partial skeleton preserved in a single mudstone block, including most skull bones, parts of the mandible, incomplete vertebral column, and apendicular skeleton (see details of the preserved elements in the Electronic Supplementary Material). Some of the elements were extracted, but most were only superficially exposed,
retaining their original position in the block.
Type locality and horizon
Reddish mudstones of the Alemoa Member, Santa Maria Formation, Rosário do Sul Group (Zerfass et al. 2003), exposed at the site known as “Janner” or “Várzea do Agudo” (53°17′34.20″ W, 29° 39′ 10.89″ S), located about 2 km west of the town of Agudo, Rio Grande do Sul, Brazil. Based on the cooccurrence of index fossils such as Exaeretodon and Hyperodapedon, the site can be assigned to the upper portions of the Hyperodapedon Assemblage Zone (Langer et al. 2007). Correlation to the better constrained Ischigualasto Formation, northwestern Argentina (Martinez et al. 2011), suggests a late Carnian age; ca. 230–228 Ma.
Diagnosis
It is distinguished from all other well-known Triassic dinosauromorphs by the following unique combination of character states (see extended diagnosis in the Electronic Supplementary Material): head longer than two thirds of the femoral length, premaxilla with short subnarial process, concave ventral margin of the premaxilla–maxilla articulation, no inset of first premaxillary or dentary tooth, premaxilla and dentary with unserrated mesial-most tooth crowns, most teeth lanceolate with coarse denticles along the carinae, sacral vertebrae with dorsoventrally expanded ribs, femur with reduced medial tuberosity (“t” in Novas 1996; Fig. 3) in the head and well-developed trochanteric shelf, epipodium significantly longer than femur.
Cabreira, Schultz, Bittencourt, Soares, Fortier, Silva & Langer 2011
Time
Triassic Late Carnian
Classification
Saurischia Sauropodomorpha [Eusaurischia ]
Diet
Herbivore?
Fossilsite
Santa Maria Formation (Rosário do Sul Group) Alemoa Member, \\\\\\\"Janner\\\\\\\" (also known as \\\\\\\"Várzea do Agudo\\\\\\\") locality, geopark of Paleorrota, southern Brazil
Info
Abstract Post-Triassic theropod, sauropodomorph, and ornithischian dinosaurs are readily recognized based on the set of traits that typically characterize each of these groups. On the contrary, most of the early members of those lineages lack such specializations, but share a range of generalized traits also seen in more basal dinosauromorphs.
Here, we report on a new Late Triassic dinosaur from the Santa Maria Formation of Rio Grande do Sul, southern Brazil. The specimen comprises the disarticulated partial skeleton of a single individual, including most of the skull bones. Based on four phylogenetic analyses, the new dinosaur fits consistently on the sauropodomorph stem, but lacks several typical features of sauropodomorphs, showing dinosaur plesiomorphies together with some neotheropod traits.
This is not an exception among basal dinosaurs, the early radiation of which is characterized by a mosaic pattern of character acquisition, resulting in the uncertain phylogenetic placement of various early members of the group.
Etymology
The generic name is derived from the Quechua word pampa (=plain), in reference to the grassland landscape that covers parts of Rio Grande do Sul, and dromaeus, variant of Greek δρομεύς (=runner), in reference to the probable cursoriality of the animal. The specific epithet honors the Brazilian palaeontologist Mário C. Barberena.
Holotype
ULBRA-PVT016 (Museu de Ciências Naturais, Universidade Luterana do Brasil, Canoas), disarticulated partial skeleton preserved in a single mudstone block, including most skull bones, parts of the mandible, incomplete vertebral column, and apendicular skeleton (see details of the preserved elements in the Electronic Supplementary Material). Some of the elements were extracted, but most were only superficially exposed,
retaining their original position in the block.
Type locality and horizon
Reddish mudstones of the Alemoa Member, Santa Maria Formation, Rosário do Sul Group (Zerfass et al. 2003), exposed at the site known as “Janner” or “Várzea do Agudo” (53°17′34.20″ W, 29° 39′ 10.89″ S), located about 2 km west of the town of Agudo, Rio Grande do Sul, Brazil. Based on the cooccurrence of index fossils such as Exaeretodon and Hyperodapedon, the site can be assigned to the upper portions of the Hyperodapedon Assemblage Zone (Langer et al. 2007). Correlation to the better constrained Ischigualasto Formation, northwestern Argentina (Martinez et al. 2011), suggests a late Carnian age; ca. 230–228 Ma.
Diagnosis
It is distinguished from all other well-known Triassic dinosauromorphs by the following unique combination of character states (see extended diagnosis in the Electronic Supplementary Material): head longer than two thirds of the femoral length, premaxilla with short subnarial process, concave ventral margin of the premaxilla–maxilla articulation, no inset of first premaxillary or dentary tooth, premaxilla and dentary with unserrated mesial-most tooth crowns, most teeth lanceolate with coarse denticles along the carinae, sacral vertebrae with dorsoventrally expanded ribs, femur with reduced medial tuberosity (“t” in Novas 1996; Fig. 3) in the head and well-developed trochanteric shelf, epipodium significantly longer than femur.