The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades

Nesbitt, Sterling J.

doi:10.1206/352.1

Cited by 727 publications

(2,798 citation statements)

References 294 publications

Supporting

Mentioning

2,561

Contrasting

Unclassified

Order By: Relevance

“…All of these findings suggest that crown-group archosaur diversification was more intimately related to recovery from the end-Permian mass extinction than previously suspected. Importantly, this early diversification included not only phylogenetic diversification, with at least five archosaur ghost lineages drawn back to the Early Triassic, but ecological expansion into a variety of carnivorous, omnivorous, and herbivorous niches (16,39).…”

Section: (Si Text)mentioning

confidence: 99%

Provincialization of terrestrial faunas following the end-Permian mass extinction

Sidor

Vilhena²,

Angielczyk

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

147

134

View full text Add to dashboard Cite

In addition to their devastating effects on global biodiversity, mass extinctions have had a long-term influence on the history of life by eliminating dominant lineages that suppressed ecological change. Here, we test whether the end-Permian mass extinction (252.3 Ma) affected the distribution of tetrapod faunas within the southern hemisphere and apply quantitative methods to analyze four components of biogeographic structure: connectedness, clustering, range size, and endemism. For all four components, we detected increased provincialism between our Permian and Triassic datasets. In southern Pangea, a more homogeneous and broadly distributed fauna in the Late Permian (Wuchiapingian, ∼257 Ma) was replaced by a provincial and biogeographically fragmented fauna by Middle Triassic times (Anisian, ∼242 Ma). Importantly in the Triassic, lower latitude basins in Tanzania and Zambia included dinosaur predecessors and other archosaurs unknown elsewhere. The recognition of heterogeneous tetrapod communities in the Triassic implies that the end-Permian mass extinction afforded ecologically marginalized lineages the ecospace to diversify, and that biotic controls (i.e., evolutionary incumbency) were fundamentally reset. Archosaurs, which began diversifying in the Early Triassic, were likely beneficiaries of this ecological release and remained dominant for much of the later Mesozoic.biogeography | complex networks | macroevolution | biotic recovery | paleoecology M ass extinctions are thought to reshape the composition and ecological structure of communities on a scale unparalleled by background extinction (1, 2). Within the terrestrial realm, the replacement of dinosaur-dominated communities by those of mammals after the end-Cretaceous extinction is perhaps the best-known example of such wholesale faunal reshuffling. By contrast, understanding the effects of the more massive endPermian extinction on terrestrial community structure has been hampered by the paucity of high-quality geographic data, with nearly all studies restricted to sequences from single basins in Russia (3, 4) or South Africa (5-8). Although some broad similarities have emerged, such as the progressive aridification of the two basins (3, 8) and a heightened diversity of temnospondyl amphibians in the recovery interval (9), limited geographic sampling in each hemisphere constrains the ability of paleontologists to distinguish regional patterns from those characteristic of the individual basins. Moreover, these broadly separated areas are uninformative regarding large-scale (i.e., continentlevel) patterns of faunal evolution.Here we examine tetrapod faunal composition in five fossiliferous areas in southern Pangea approximately 5 million years before and 10 million years after the end-Permian mass extinction. We analyze changes in biogeographic structure with four metrics of taxon occurrence data. First, biogeographic connectedness (BC) quantifies the proportion of taxon-locality occurrences relative to the maximum number of such occurrences possible. Thus...

show abstract

Section: (Si Text)mentioning

confidence: 99%

Provincialization of terrestrial faunas following the end-Permian mass extinction

Sidor

Vilhena²,

Angielczyk

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

147

134

View full text Add to dashboard Cite

show abstract

“…Archosauria is divided into two major clades: the Pseudosuchia, which includes modern crocodilians and all archosaurs more closely related to crocodilians than to birds, and the Avemetatarsalia or Ornithodira, which contains pterosaurs, silesaurids, and dinosaurs, including birds (Nesbitt, 2011). The Pseudosuchia were most successful and diverse (both ecologically and morphologically) during the Late Triassic (Brusatte et al, 2008;Foth et al, 2016), including quadrupedal and (facultative) bipedal forms, terrestrial and semiaquatic life styles, as well as piscivorous, carnivorous, or omnivorous diet preferences (e.g., Desojo and Vizca ıno, 2009;Gauthier et al, 2011;Nesbitt et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…The Pseudosuchia were most successful and diverse (both ecologically and morphologically) during the Late Triassic (Brusatte et al, 2008;Foth et al, 2016), including quadrupedal and (facultative) bipedal forms, terrestrial and semiaquatic life styles, as well as piscivorous, carnivorous, or omnivorous diet preferences (e.g., Desojo and Vizca ıno, 2009;Gauthier et al, 2011;Nesbitt et al, 2013). According to Nesbitt (2011), Pseudosuchia contain Ornithosuchidae, Aetosauria, Poposauroidea, Rauisuchidae, and Crocodylomorpha, but probably also the long-snouted Phytosauria (see Brusatte et al, 2010;Ezcurra, 2016). Except for Crocodylomorpha, the group went extinct at the end of the Triassic (Nesbitt, 2011;Toljagic and Butler, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…According to Nesbitt (2011), Pseudosuchia contain Ornithosuchidae, Aetosauria, Poposauroidea, Rauisuchidae, and Crocodylomorpha, but probably also the long-snouted Phytosauria (see Brusatte et al, 2010;Ezcurra, 2016). Except for Crocodylomorpha, the group went extinct at the end of the Triassic (Nesbitt, 2011;Toljagic and Butler, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…It was quadrupedal, and its postcranial morphology suggests an erect posture (see Benton, 1984). Batrachotomus was formerly thought to be a member of Prestosuchidae (Gower, 2002;Brusatte et al, 2010), but other phylogenetic analyses found it more closely related to Crocodylomorpha and Rauisuchidae (Nesbitt, 2011;Li et al, 2012;Sues and Schoch, 2013).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Preliminary observations on the bone histology of the Middle Triassic pseudosuchian archosaurBatrachotomus kupferzellensisreveal fast growth with laminar fibrolamellar bone tissue

Klein

Foth

Schoch

2017

Journal of Vertebrate Paleontology

View full text Add to dashboard Cite

ABSTRACT-The bone tissue of femur, rib, and gastralia from three different individuals of the Middle Triassic pseudosuchian Batrachotomus kupferzellensis from southern Germany is studied. The femoral bone tissue comprises laminar fibrolamellar bone tissue throughout and is stratified by three annual growth cycles, indicating that the individual died early in its fourth year of life, at which time it had reached 87% of maximum known femur length. Thus, compared with most other Pseudosuchia (e.g., phytosaurs, aetosaurs, and most crocodylomorphs, including marine taxa), Batrachotomus achieved its large body size in a very short time by fast, although interrupted, growth and not by protracted longevity. Such fast growth as well as the organization of the tissue is similar to the condition observed in ornithodirans. The pseudosuchians Effigia and Postosuchus also show fibrolamellar tissue, but vascular density is lower when compared with Batrachotomus and dominated by a longitudinal organization of primary osteons. The rib and gastralium of Batrachotomus both show an inner spongious organization surrounded by a ring of compact, avascular, highly organized parallel-fibered and/or lamellar bone largely covered by short fibers. Maximal growth cycle count in the proximal rib sample suggests an age of at least 11 years for this individual with a reduction of growth rate after the sixth cycle.

show abstract

Dinosaurs and The Origin of Birds

Clark

2013

Encyclopedia of Life Sciences

View full text Add to dashboard Cite

The evolutionary relationships of birds have been debated ever since the discovery of a fossil bird, Archaeopteryx , in 1861, that has bird‐like feathers but reptilian teeth and a long bony tail. Recent discoveries of feathered dinosaurs have confirmed analyses of bird relationships beginning in the 1970s that placed Archaeopteryx and birds within one group of dinosaurs, the Theropoda. Recognition of this relationship and discovery of a variety of new species have allowed evolutionary biologists to study for the first time many aspects of the transition from ground‐living theropods to flying birds. Many new details about the evolution of feathers, reproductive features of birds and flight have emerged from these fossils and continue to emerge as new fossils are found. The precise relationships of birds to theropods is still debated, but the scansoriopterygids, dromaeosaurs and troodontids are amongst the closest relatives of birds. Key Concepts: The closest living relatives of birds are the crocodilians and together they form the group Archosauria. The origins of birds lie with fossil archosaurs, which include dinosaurs, the flying reptiles called pterosaurs and the many fossil relatives of crocodilians. Evolutionary relationships are studied using cladistic analysis of similarities shared amongst different species. Cladistic analyses strongly support birds being closely related to a subgroup within the theropod dinosaurs called Coelurosauria and especially with the scansoriopterygid, dromaeosaur and troodontid coelurosaurs. Fossil coelurosaurs with feathers from China provide convincing evidence that birds are coelurosaurs, and that during the course of evolution feathers arose before flight.

show abstract

The Early Evolution of Archosaurs: Relationships and the Origin of Major Clades

Cited by 727 publications

References 294 publications

Provincialization of terrestrial faunas following the end-Permian mass extinction

Provincialization of terrestrial faunas following the end-Permian mass extinction

Preliminary observations on the bone histology of the Middle Triassic pseudosuchian archosaurBatrachotomus kupferzellensisreveal fast growth with laminar fibrolamellar bone tissue

Dinosaurs and The Origin of Birds

Contact Info

Product

Resources

About