Stratigraphy, palynology, and conchostracans of a Lower Cretaceous sequence at the Cañadón Calcáreo locality, Extra-Andean central Patagonia: age and palaeoenvironmental significance

Volkheimer, Wolfgang; Gallego, Oscar Florencio; Cabaleri, Nora Graciela; Armella, Claudia; Narváez, Paula Liliana; Nieto, Diego G. Silva; Paez, M.

doi:10.1016/j.cretres.2008.07.010

Cited by 50 publications

(27 citation statements)

References 15 publications

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“…Queso Rallado consists of outcrops of the Cañadón Asfalto Formation (Stipanicic et al, 1968), which is considered to be Early to Middle Jurassic in age (Cúneo et al, 2013;Nullo and Proserpio, 1975;Tasch and Volkheimer, 1970;Volkheimer et al, 2009). The Cañadón Asfalto Formation is represented by calcareous, silicoclastic, and volcanic deposits related to the evolution of the Cañadón Asfalto Basin (Figari et al, 1996, and references cited therein).…”

Section: Methodsmentioning

confidence: 98%

Bone shell microstructure of Condorchelys antiqua Sterli, 2008, a stem turtle from the Jurassic of Patagonia

Cerda

Sterli

Scheyer

2016

Comptes Rendus Palevol

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Please cite this article in press as:Cerda, I.A., et al., Bone shell microstructure of Condorchelys antiqua Sterli, 2008, a stem turtle from the Jurassic of Patagonia. C. R. Palevol (2015), http://dx. a b s t r a c tThe histology of the turtle shell has proven to be a valuable source of characters for the study of development and shell origin, as well as early turtles' lifestyles and systematics. Here we describe and discuss the shell bone microanatomy and histology of Condorchelys antiqua, a stem turtle from the Lower Jurassic of Patagonia. Examination of several elements (including costals, neurals, peripherals and plastral plates) reveals that the shell bones consist of a diploe structure in which the interior area of cancellous bone is framed by external and internal cortices. Whereas the external cortex is mostly composed of structural fiber bundles, histological composition of the internal cortex is more variable, exhibiting structural fiber bundles and/or parallel fibered bone. This histological variation in the internal cortex allows discerning between different types of plates. The cancellous bone is mostly well developed and consists of fine trabeculae composed of secondary lamellar bone tissue. Predominance of structural fiber bundles in the shell bones suggests that metaplasia plays an important role during the development of the shell in this taxon. Comparison with other stem Testudines (including Proganochelys quenstedti, Proterochersis robusta, Kayentachelys sp., Eileanchelys waldmani, and Heckerochelys romani) reveals that the shell histology of C. antiqua resembles more H. romani and E. waldmani than the other stem taxa. The obtained values of compactness of C. antiqua shell bones suggest an aquatic lifestyle for this taxon.

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Section: Methodsmentioning

confidence: 98%

Bone shell microstructure of Condorchelys antiqua Sterli, 2008, a stem turtle from the Jurassic of Patagonia

Cerda

Sterli

Scheyer

2016

Comptes Rendus Palevol

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“…Thick sandstone channels a few meters above the fish beds mark the change to more fluvial conditions in the upper part of the sequence, which is dominated by sandstones (often with channel structures and cross-bedding), tuffites and tuffs. This general sequence is equivalent to that of the Cañadón Calcáreo type locality (see Volkheimer et al, 2009), and a visit to this locality in 2009 also led to the discovery of fish remains in the lacustrine shales in the lower part of this section. Furthermore, we collected samples of tuff layers at Puesto Almada and the Cañadón Calcáreo type locality that yielded equivalent ages of c. 157.4 Ma (Oxfordian; Cúneo et al, 2013).…”

Section: Geological Settingsmentioning

confidence: 99%

“…Thus, we consider the "estratos de Almada" to be equivalent to the Cañadón Calcáreo Formation of Proserpio (1987). Volkheimer et al (2009) argued that the Cañadón Calcáreo Formation at its type locality is overlain in an erosional unconformity by the Chubut Group. However, our own observations in the field indicate that this presumed unconformity actually represents a local formation of an erosional basis of a river channel and cannot be traced laterally over larger distances.…”

Section: Geological Settingsmentioning

confidence: 99%

“…Following this revision, and based on own observations in the field, Rauhut (2003Rauhut ( , 2006aRauhut ( , 2006b, López-Arbarello (2004), Rauhut et al (2005), López-Arbarello et al (2008), andCarballido et al (2011) referred to this unit as Cañadón Calcáreo Formation, including the "estratos de Almada" (Figure 1). Although Volkheimer et al (2008Volkheimer et al ( , 2009) accepted the referral of the "estratos de Almada" to the Cañadón Calcáreo Formation, assigning an Early Cretaceous (Valanginian) age FIGURE 2. Geographic location of the fish localities: 1, Puesto Almada; 2, Punta Biotita; 3.…”

Section: Geological Settingsmentioning

confidence: 99%

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A new genus of coccolepidid fishes (Actinopterygii, Chondrostei) from the continental Jurassic of Patagonia

López‐Arbarello

Sferco

Rauhut

2013

Palaeontologia Electronica

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Jurassic freshwater fish faunas are still poorly known, with the only assemblage of that age known from southern South America being the "Almada fauna" of the Cañadón Calcáreo Formation (Oxfordian-Tithonian) of Chubut, Argentina. This fauna is composed mainly by abundant teleosts and a much rarer basal actinopterygian, originally described as †Oligopleurus groeberi and currently usually placed in the genus †Coccolepis. This taxon is here redescribed on the basis of the original specimens and more numerous and better preserved new material from several localities within the Cañadón Calcáreo Formation. The species shows several differences to other coccolepidid taxa, including the apomorphic presence of a sensory canal in the gular plate, and cannot be referred to a known genus. Thus, a new genus name, †Condorlepis gen. nov., is proposed. The detailed anatomical description of †Condorlepis gen. nov. groeberi provides further evidence for the chondrostean affinities of the Coccolepididae and their close relationships with the Acipenseriformes, since this species shows six characters that were hitherto considered to be autapomorphies of the latter clade. A comparison of the Almada fauna with other Gondwanan Jurassic freshwater fish faunas shows close similarities with the roughly contemporaneous fauna of Talbragar, Australia, which also includes an abundant basal teleost and coccolepidids. In contrast, there are marked differences with the faunas of the Early to Middle Jurassic Kota Formation of India, the Late Jurassic to Early Cretaceous Stanleyville beds of the Democratic Republic of the Congo, and the probably Late Jurassic Tacuarembó Formation of Uruguay, in which basal, non-teleostean neopterygians and sarcopterygians are abundant.

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“…However, isolated records of Barremian angiosperm pollen based on borehole material was referred to the Springhill Formation (Archangelsky and Archangelsky 2004;Quatrocchio et al 2006). The Cañ adó n Calcá reo Formation from Chubut province (southern Patagonia) also yielded a Late JurassicHauterivian pollen assemblage without angiosperms (Volkheimer et al 2009, fig. 1).…”

Section: Comparisonsmentioning

confidence: 99%

Aptian Angiosperm Pollen from the Ticó Flora Patagonia, Argentina

Archangelsky

2013

International Journal of Plant Sciences

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Stratigraphy, palynology, and conchostracans of a Lower Cretaceous sequence at the Cañadón Calcáreo locality, Extra-Andean central Patagonia: age and palaeoenvironmental significance

Cited by 50 publications

References 15 publications

Bone shell microstructure of Condorchelys antiqua Sterli, 2008, a stem turtle from the Jurassic of Patagonia

Bone shell microstructure of Condorchelys antiqua Sterli, 2008, a stem turtle from the Jurassic of Patagonia

A new genus of coccolepidid fishes (Actinopterygii, Chondrostei) from the continental Jurassic of Patagonia

Aptian Angiosperm Pollen from the Ticó Flora Patagonia, Argentina

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