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First 'Rauisuchian' archosaur (Pseudosuchia, Loricata) for the Middle Triassic Santacruzodon assemblage zone (Santa Maria Supersequence), Rio Grande do Sul State, Brazil.

Lacerda MB, Schultz CL, Bertoni-Machado C - PLoS ONE (2015)

Bottom Line: In Brazil, their fossils are found only in the Santa Maria Formation (Paraná Basin) of the Rio Grande do Sul State, specifically in the Middle Triassic Dinodontosaurus assemblage zone (AZ) and the Late Triassic Hyperodapedon AZ (Rauisuchus tiradentes).Between these two cenozones is the Santacruzodon AZ (Middle Triassic), whose record was, until now, restricted to non-mammalian cynodonts and the proterochampsian Chanaresuchus bonapartei.Here we present the first occurrence of a rauisuchian archosaur for this cenozone, from the Schoenstatt outcrop, located near the city of Santa Cruz do Sul and propose a new species, based on biostratigraphical evidence and a comparative osteological analysis.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Geociências, Laboratório de Paleovertebrados, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.

ABSTRACT
The 'Rauisuchia' are a group of Triassic pseudosuchian archosaurs that displayed a near worldwide distribution. In Brazil, their fossils are found only in the Santa Maria Formation (Paraná Basin) of the Rio Grande do Sul State, specifically in the Middle Triassic Dinodontosaurus assemblage zone (AZ) and the Late Triassic Hyperodapedon AZ (Rauisuchus tiradentes). Between these two cenozones is the Santacruzodon AZ (Middle Triassic), whose record was, until now, restricted to non-mammalian cynodonts and the proterochampsian Chanaresuchus bonapartei. Here we present the first occurrence of a rauisuchian archosaur for this cenozone, from the Schoenstatt outcrop, located near the city of Santa Cruz do Sul and propose a new species, based on biostratigraphical evidence and a comparative osteological analysis.

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Related in: MedlinePlus

Left ilium (UFRGS-PV-1244-T) in lateral (A) and medial (B) views.Abbreviations: ac, acetabule; ilba, iliac blade; prap, pre-acetabular process; poap, post-acetabular process; sar, supra-acetabular crest; sacr, supra-acetabular ridge. Scale: 5cm.
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pone.0118563.g003: Left ilium (UFRGS-PV-1244-T) in lateral (A) and medial (B) views.Abbreviations: ac, acetabule; ilba, iliac blade; prap, pre-acetabular process; poap, post-acetabular process; sar, supra-acetabular crest; sacr, supra-acetabular ridge. Scale: 5cm.

Mentions: The ilium is well preserved, with roughly 19 cm in length and 10 cm tall (Fig. 3). The contact of the blade with the acetabular area is continuous, not displaying a waisted region between both areas. The former is overall complete, with what appears to be only minor damage on both extremities. The dorsal margin of the iliac blade, in lateral view, is smooth and straight, with no sign of any rugose surface as those described for Batrachotomus and Prestosuchus. Perpendicular to its longitudinal axis there is a low (but distinct) antero-posteriorlly wide ridge that projects antero-dorsally on its lateral area from the dorsal border of a robust supra-acetabular crest, dividing the iliac blade into a short preacetabular and longer postacetabular process. The former has the same length as the anterior margin of the acetabular region, with the area near the anterior margin of the crest being preserved, while the postacetabular process projects antero-posteriorlly into a dorso-ventrally tall and compressed blade of bone that slightly tapers posteriorly. The ventroposterior portion of this blade is gently expanded laterally, which occupies the rest of the posterior tip


First 'Rauisuchian' archosaur (Pseudosuchia, Loricata) for the Middle Triassic Santacruzodon assemblage zone (Santa Maria Supersequence), Rio Grande do Sul State, Brazil.

Lacerda MB, Schultz CL, Bertoni-Machado C - PLoS ONE (2015)

Left ilium (UFRGS-PV-1244-T) in lateral (A) and medial (B) views.Abbreviations: ac, acetabule; ilba, iliac blade; prap, pre-acetabular process; poap, post-acetabular process; sar, supra-acetabular crest; sacr, supra-acetabular ridge. Scale: 5cm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4340915&req=5

pone.0118563.g003: Left ilium (UFRGS-PV-1244-T) in lateral (A) and medial (B) views.Abbreviations: ac, acetabule; ilba, iliac blade; prap, pre-acetabular process; poap, post-acetabular process; sar, supra-acetabular crest; sacr, supra-acetabular ridge. Scale: 5cm.
Mentions: The ilium is well preserved, with roughly 19 cm in length and 10 cm tall (Fig. 3). The contact of the blade with the acetabular area is continuous, not displaying a waisted region between both areas. The former is overall complete, with what appears to be only minor damage on both extremities. The dorsal margin of the iliac blade, in lateral view, is smooth and straight, with no sign of any rugose surface as those described for Batrachotomus and Prestosuchus. Perpendicular to its longitudinal axis there is a low (but distinct) antero-posteriorlly wide ridge that projects antero-dorsally on its lateral area from the dorsal border of a robust supra-acetabular crest, dividing the iliac blade into a short preacetabular and longer postacetabular process. The former has the same length as the anterior margin of the acetabular region, with the area near the anterior margin of the crest being preserved, while the postacetabular process projects antero-posteriorlly into a dorso-ventrally tall and compressed blade of bone that slightly tapers posteriorly. The ventroposterior portion of this blade is gently expanded laterally, which occupies the rest of the posterior tip

Bottom Line: In Brazil, their fossils are found only in the Santa Maria Formation (Paraná Basin) of the Rio Grande do Sul State, specifically in the Middle Triassic Dinodontosaurus assemblage zone (AZ) and the Late Triassic Hyperodapedon AZ (Rauisuchus tiradentes).Between these two cenozones is the Santacruzodon AZ (Middle Triassic), whose record was, until now, restricted to non-mammalian cynodonts and the proterochampsian Chanaresuchus bonapartei.Here we present the first occurrence of a rauisuchian archosaur for this cenozone, from the Schoenstatt outcrop, located near the city of Santa Cruz do Sul and propose a new species, based on biostratigraphical evidence and a comparative osteological analysis.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Geociências, Laboratório de Paleovertebrados, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.

ABSTRACT
The 'Rauisuchia' are a group of Triassic pseudosuchian archosaurs that displayed a near worldwide distribution. In Brazil, their fossils are found only in the Santa Maria Formation (Paraná Basin) of the Rio Grande do Sul State, specifically in the Middle Triassic Dinodontosaurus assemblage zone (AZ) and the Late Triassic Hyperodapedon AZ (Rauisuchus tiradentes). Between these two cenozones is the Santacruzodon AZ (Middle Triassic), whose record was, until now, restricted to non-mammalian cynodonts and the proterochampsian Chanaresuchus bonapartei. Here we present the first occurrence of a rauisuchian archosaur for this cenozone, from the Schoenstatt outcrop, located near the city of Santa Cruz do Sul and propose a new species, based on biostratigraphical evidence and a comparative osteological analysis.

Show MeSH
Related in: MedlinePlus