Diagenetic pattern of vertebrate fossils from the Traversodontidae Biozone, Santa Maria Formation (Triassic), southern Brazil

Reichel, Miriam; Schultz, César Leandro; Pereira, Vitor Paulo

doi:10.4072/rbp.2005.3.01

Cited by 16 publications

(10 citation statements)

References 22 publications

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“…In our case, the position of siderite in external part of vascular canals of cynodont rib (MHNSR.Pv.1159) recovered in a floodplain could suggest oxygenation of the bone interior. Similar diagenetic features have been identified in other vertebrate bone remains (Holz and Schultz, 1998;Reichel et al, 2005;González Riga and Astini, 2007;González Riga et al, 2009;Previtera, 2011Previtera, , 2013Previtera et al, 2013;Casal et al, 2013, among others).…”

Section: Discussionsupporting

confidence: 70%

Diagenetic analysis of tetrapod from the Upper Triassic, Puesto Viejo Group, Argentina

Previtera

Mancuso

Fuente

et al. 2016

andgeo

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The Puesto Viejo Group crops out in the San Rafael Block, southwest Mendoza, Argentina. This group is an important unit for the knowledge theTriassic faunas. It is composed of basal Quebrada de los Fósiles Formation (QF) overlying by the Río Seco de la Quebrada Formation (RSQ). In this study, we report tetrapod remains from the RSQ Formation that includes, until now, exclusively therapsids. Non-mammalian therapsids predominated in terrestrial ecosystems during the Late Paleozoic and Early Mesozoic. Although cynodonts and dicynodonts have been studied from several perspectives, the relation between taxa and sedimentary context has been scarcely documented. This study is aimed to elucidate the diagenesis of tetrapods from the Puesto Viejo Group and its relation to depositional environment. Diagenetic features of therapsid bones from the RSQ Formation were analyzed through thin sections to interpret the degree of taphonomic alteration. Diagenetic processes inferred include substitution; fracturing; brittle deformation and different permineralization events. Combined analyses through scanning electron microscopy; energy-dispersive X-ray spectrometry (SEM-EDX); X-ray diffractometry (XRD) and petrographic studies reveals the substitution of hydroxyapatite by francolite. The presence of fluorine in some samples suggests a link between the elemental composition and depositional environments: floodplain and crevasse splay. Permineralization stages include infilling of vascular canals, trabeculae and fractures with iron oxides and iron carbonate minerals during the burial history. This contribution represents a relevant approach to elucidate the relation between diagenesis on tetrapods and their paleoenvironments, as exemplified in this case study from the Puesto Viejo Group during the Upper Triassic.

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Section: Discussionsupporting

confidence: 70%

Diagenetic analysis of tetrapod from the Upper Triassic, Puesto Viejo Group, Argentina

Previtera

Mancuso

Fuente

et al. 2016

andgeo

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“…These processes are the result of differences in burial depth, temperature and geostatic pressure suffered by the fossils in each burial environment. Similar diagenetic features have been identified in other vertebrate remains (Holz and Schultz, 1998;Wings, 2004;Reichel et al, 2005;González Riga and Astini, 2007;González Riga et al, 2009;Casal et al, 2013;Previtera, 2011Previtera, , 2013Previtera et al, 2013;Previtera et al, 2016).…”

Section: Taphonomic Pathwayssupporting

confidence: 51%

Bone microstructure and diagenesis of saurischian dinosaurs from the Upper Cretaceous (Neuquén Group), Argentina

Previtera

2017

andgeo

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ABSTRACT. The Neuquén Basin in northwestern Patagonia, Argentina, holds the most important record of Cretaceous dinosaurs in South America.The Neuquén Group (Upper Cretaceous) is the richest dinosaur-bearing unit of the basin. It comprises the Río Limay, the Río Neuquén and the Río Colorado subgroups. In this study, dinosaur remains from the Río Neuquén and the Río Colorado subgroups outcropping in Mendoza are examined. In this group, isolated, disarticulated or partially articulated sauropods and theropods are abundant. However, little is known about the diagenetic history of fossil assemblages. In southern Mendoza, three fossiliferous sites were found in the areas of Paso de las Bardas (Quebrada Norte) and Cerro Guillermo (CG1, CG2). This study aims to add to the knowledge of diagenetic processes involving dinosaur remains from the Neuquén Group, as well as their relation to the depositional environment. Histologic features and diagenetic processes of dinosaur bones were analyzed through thin sections in order to interpret the degree of taphonomic alteration. The fossil-diagenetic processes inferred include substitution, fracturing, plastic deformation and different permineralization events. Combined analyses through X-ray diffractometry (XRD) and petrographic studies reveal the substitution of hydroxyapatite by francolite. The presence of fluorine -in one of the cases-suggests a link between the elemental composition and depositional environments: floodplain and fluvial channel. Permineralization stages include infilling of vascular canals, trabeculae and fractures with iron oxides and iron carbonate minerals during the burial history. This contribution represents an integral approach to the study of Cretaceous dinosaurs for assessing the diagenetic changes in the bone microstructure and the differential preservation of fossil remains in fluvial environments.

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“…In addition to the morphological similarities of the traversodontids, the fossils from these three localities show the same diagenetic pattern, with a predominance of quartz permineralization, differing from other Triassic localities (Dinodontosaurus and Hyperodapedon assemblage zones) where there is a predominance of calcitic permineralization (Reichel et al, 2005;Teixeira et al, 2010). This new information allows for the geographic expansion of the Santacruzodon Assemblage Zone.…”

Section: Study Area and Biostratigraphymentioning

confidence: 93%

“…More recently, traversodontids with similarities to those from Santa Cruz do Sul were discovered in two other outcrops in the Venâncio Aires and Vera Cruz municipalities in Rio Grande do Sul (Reichel et al, 2005;Melo et al, 2010;Soares et al, 2011b). In addition to the morphological similarities of the traversodontids, the fossils from these three localities show the same diagenetic pattern, with a predominance of quartz permineralization, differing from other Triassic localities (Dinodontosaurus and Hyperodapedon assemblage zones) where there is a predominance of calcitic permineralization (Reichel et al, 2005;Teixeira et al, 2010).…”

Section: Study Area and Biostratigraphymentioning

confidence: 94%

The Malagasy cynodontMenadon besairiei(Cynodontia; Traversodontidae) in the Middle–Upper Triassic of Brazil

Melo¹,

Abdala²,

Soares³

2015

Journal of Vertebrate Paleontology

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The traversodontid cynodont Menadon besairiei, previously known from the 'Isalo II' group of Madagascar, is reported for the first time from the Triassic of southern Brazil. New material referable to M. besairiei was collected in the Schoenstatt outcrop (Santa Cruz do Sul municipality), which belongs to the Santacruzodon Assemblage Zone (Carnian) in the Santa Maria Supersequence. Their attribution to the Malagasy taxon is based on the presence of a deep snout; four upper incisors, with procumbent first and second incisors, and three lower, procumbent incisors; five upper postcanines, the first one 'peg-like'; six lower postcanines, the two most anterior and the most posterior being reduced; the quadrangular form of the postcanines; a pterygoid reaching the jugal and excluding the maxilla from the suborbital fenestra; a mandible with a tall coronoid process covering the last lower postcanine laterally; and a posteriorly projected angular process. A cladistic analysis of traversodontid cynodonts was performed based on a matrix composed of 30 taxa and 78 characters. In the resulting trees, M. besairiei nested within the clade Gomphodontosuchinae, the only traversodontid subclade reasonably well supported. Thus, the presence of M. besairiei is established in the Santa Cruz do Sul fauna, constituting the first record for South America and confirming the previously proposed biostratigraphic correlation between the 'Isalo II' and the Santacruzodon Assemblage Zone. Citation for this article: Melo, T. P., F. Abdala, and M. B. Soares. 2015. The Malagasy Cynodont Menadon Besairiei (Cynodontia; Traversodontidae) in the Middle-Upper Triassic of Brazil. Journal of Vertebrate Paleontology.

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Diagenetic pattern of vertebrate fossils from the Traversodontidae Biozone, Santa Maria Formation (Triassic), southern Brazil

Cited by 16 publications

References 22 publications

Diagenetic analysis of tetrapod from the Upper Triassic, Puesto Viejo Group, Argentina

Diagenetic analysis of tetrapod from the Upper Triassic, Puesto Viejo Group, Argentina

Bone microstructure and diagenesis of saurischian dinosaurs from the Upper Cretaceous (Neuquén Group), Argentina

The Malagasy cynodontMenadon besairiei(Cynodontia; Traversodontidae) in the Middle–Upper Triassic of Brazil

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