A new coelurosaurian dinosaur from the Early Cretaceous of South Africa

Klerk, William J. De; Forster, Catherine A.; Sampson, Scott D.; Chinsamy, Anusuya; Ross, Callum F.

doi:10.1671/0272-4634(2000)020[0324:ancdft]2.0.co;2

Cited by 76 publications

(63 citation statements)

References 21 publications

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“…The synapomorphies that are shared by the coelurosaurs more derived than Bicentenaria include: quadratojugal with a rostral process shorter than the dorsal one, caudal vertebrae with undivided neural spines, distal end of femur without a mediodistal crest (apomorphically reversed in tyrannosaurids), and astragalus with a transversely broad and tall ascending process. In the present analysis, the Brazilian Mirischia (Naish et al, 2004) and the South African Nqwebasaurus (De Clerk et al, 2000) are nested within Compsognathidae, indicating a cosmopolitan distribution for this family during, at least, the Early Cretaceous. The problematic Brazilian Santanaraptor (Kellner, 1999) & Novas, 2006).…”

Section: Discussionmentioning

confidence: 48%

“…Most of these clades are well documented in the Northern Hemisphere, and although the record of Coelurosauria in the southern landmasses is still limited, discoveries produced in Patagonia in the last 15 years have favourably changed this situation . In particular, the fossil record of non-maniraptoran coelurosaurs in Gondwana is currently composed by Mirischia asymmetrica (Santana Formation, Aptian, Brazil; Naish et al, 2004) and Nqwebasaurus thwazi (Kirkwood Formation, probably Valanginian;De Clerk et al, 2000), both possible compsognathids, and the yet poorly understood Aniksosaurus darwini (Lower Bajo Barreal Formation, Cenomanian; Martínez & Novas, 2007) and Santanaraptor placidus (Santana Formation, Aptian, Brazil;Kellner, 1999).…”

Section: Introductionmentioning

confidence: 99%

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New Patagonian Cretaceous theropod sheds light about the early radiation of Coelurosauria

Novas¹,

Ezcurra²,

Agnolín³

et al. 2012

MACN

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Abstract:Here we describe a new theropod, Bicentenaria argentina nov. gen. et nov. sp., from the early Late Cretaceous of Patagonia. It is represented by more than a hundred bones belonging to different sized individuals, which were buried together in disarticulation after little transportation. The available association of skeletal elements suggests a gregarious behaviour for Bicentenaria, an ethological trait also recorded among other theropod clades. Increasing documentation of monospecific assemblages of different groups of theropods suggests that a gregarious behaviour may have constituted the ancestral condition for Theropoda, at least. Bicentenaria characterizes for the surangular bone with a high dorsal margin and a prominent lateral shelf, a retroarticular process that is low, wide and spoon-shaped, and quadrate bone with its lateral condyle larger than the medial one. Phylogenetic analysis found the Chinese Tugulusaurus and the Patagonian Bicentenaria as successive sister taxa of all other coelurosaurs, thus revealing the importance of the new taxon in the understanding of the early diversification of Coelurosauria. In particular, Bicentenaria amplifies the array of basal coelurosaurs that inhabited Gondwana during the Cretaceous, also including compsognathids, Aniksosaurus and Santanaraptor. Although still restricted to a handful of forms, available information indicates that Gondwana was a cradle for the evolution of different lineages of basal coelurosaurs, different from those documented in Upper Cretaceous beds in the northern landmasses. Analysis of body size distribution in averostran theropods results in the identification of two main episodes of drastic size reduction in the evolutionary history of Coelurosauria: one occurred at the initial radiation of the group (as represented by Bicentenaria, Zuolong, Tugulusaurus, compsognathids, and Aniksosaurus), and a second episode occurred at the early diverification of Paraves or avialans. Reduction in body size may have allowed adult coelurosaurians to exploit ecological niches not occupied before by larger basal averostrans.Key words: Coelurosauria, gregarism, body size reduction, Cretaceous, South America.Resumen: Nuevo terópodo del Cretácico de Patagonia brinda nuevas evidencias acerca de la radiación temprana de Coelurosauria. En la presente contribución se describe el nuevo terópodo Bicentenaria argentina nov. gen. et nov. sp., del Cretácico Tardío temprano de Patagonia. El nuevo taxón se encuentra representado por más de una centena de huesos pertenecientes a individuos de diferentes tamaños, los cuales fueron enterrados todos juntos en desarticulación, luego de un leve transporte. La asociación disponible de materiales sugiere hábitos gregarios para Bicentenaria, un rasgo etológico también registrado en otros clados de terópodos. La documentación recurrente de asociaciones monoespecíficas de diferentes grupos de terópodos sugiere que los hábitos gregarios pudieron haber constituido la condición ancestral para Theropoda. Bicentenaria se caract...

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Section: Discussionmentioning

confidence: 48%

Section: Introductionmentioning

confidence: 99%

New Patagonian Cretaceous theropod sheds light about the early radiation of Coelurosauria

Novas¹,

Ezcurra²,

Agnolín³

et al. 2012

MACN

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“…Unlike these taxa, Scipionyx has a stouter scapula -with an estimated length of about seven times the width of the mid-shaft -even if the proportion of this bone with respect to the humerus is comparable to that of Compsognathus. The scapula of Juravenator differs from that of Sinosauropteryx as well as from that of other "compsognathids" by the fact that the narrowest portion of the scapula is at the neck as opposed to near the mid-shaft -in this respect the scapula of Juravenator resembles more that of the basal coelurosaurs Nqwebasaurus (DE KLERK et al 2000) and Tyrannosaurus [BROCHU 2003; but not basal tyrannosauroids such as Dilong (XU et al 2004) in which the scapula is very robust. The lateral surface of the scapula is virtually flat, although it is more concave in cross-section along the ventral third of its blade (its basal portion).…”

Section: Postcraniummentioning

confidence: 85%

“…The tail includes 44 vertebrae preserved in articulation but it is unclear whether the centrum of the first caudal is missing (see above). Comparisons of the number of caudal vertebrae and relative tail length with other basal coelurosaurs are hampered by the incomplete nature of the tail of most taxa (e. g., OSTROM 1978; DAL SASSO & SIGNORE 1998;KIRKLAND et al 1998;DE KLERK et al 2000;HWANG et al 2004;NAISH et al 2004). However, meaningful comparisons can be established with the tail of the holotype of Sinosauropteryx (NIGP 127586, CHEN et al 1998;CURRIE & CHEN 2001).…”

Section: Postcraniummentioning

confidence: 99%

Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany

Chiappe¹,

Göhlich²

2010

njgpa

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“…Assuming that Aniksosaurus is a basal coelurosaur, it is required to examine briefly its relationships with other representatives: Aniksosaurus resembles the compsognathid Sinosauropteryx (Currie & Chen, 2001) and the bizarre coelurosaur Nqwebasaurus (De Klerk et al, 2000), in the robust construction of the humerus and manual unguals, although other basal tetanurans (as for example, Allosaurus, Piatnitzkysaurus, Torvosaurus) also exhibit proportionally shortened humeri and manual unguals of ponderous construction. Moreover, no distinctive features of Compsognathidae are identified in the Patagonian taxon, thus reference of Aniksosaurus to this coelurosaurian clade is untenable.…”

Section: Discussionmentioning

confidence: 99%

Aniksosaurus darwini gen. et sp. nov., a new coelurosaurian theropod from the Early Late Cretaceous of Central Patagonia, Argentina

Martı́nez¹,

Novas²

2006

MACN

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Abstract:The theropod dinosaur Aniksosaurus darwini gen. et sp. nov. has been recovered from the Upper Cretaceous, Bajo Barreal Formation, of Central Patagonia. Aniksosaurus darwini gen. et sp. nov. was a small tetanurine, approximately 2 meters long. Aniksosaurus exhibits several unique traits (e.g., cranial cervical vertebrae with dorsoventrally deep neural arches, provided with a pair of cavities at their cranial surfaces; neural canal wide; cranial caudals with ventral sagittal keel, and transverse processes triangular-shaped in dorsal view; manual ungual phalanges robust; ilium with extremely expanded brevis shelf; femur with deep notch for M. Iliotrochantericus; metatarsal and digit IV of pes transversely narrow). Available postcranial bones of Aniksosaurus exhibit derived features of Coelurosauria (e.g., ilium with well developed cuppedicus fossa; femur with anterior trochanter proximally projected, almost reaching the level of the articular head; greater trochanter craniocaudally expanded; femoral head rectangular-shaped in cranial aspect; and fibular shaft craniocaudally narrow), as well as characteristics suggesting that the new Patagonian taxon is more derived than some basal coelurosaurians such as compsognathids, Ornitholestes, and coelurids. Comparisons with maniraptoriforms (a clade including Ornithomimosauria, Tyrannosauridae, Oviraptorosauria, Alvarezsauridae and Paraves) support that Aniksosaurus is less derived than these theropods. In sum, Aniksosaurus is here considered as a Late Cretaceous survivor of a basal coelurosaurian radiation.

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A new coelurosaurian dinosaur from the Early Cretaceous of South Africa

Cited by 76 publications

References 21 publications

New Patagonian Cretaceous theropod sheds light about the early radiation of Coelurosauria

New Patagonian Cretaceous theropod sheds light about the early radiation of Coelurosauria

Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany

Aniksosaurus darwini gen. et sp. nov., a new coelurosaurian theropod from the Early Late Cretaceous of Central Patagonia, Argentina

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