A new aetosaur (Reptilia: Archosauria) from the Upper Triassic of Texas and the phylogeny of aetosaurs

Heckert, Andrew B.; Lucas, Spencer G.

doi:10.1080/02724634.1999.10011122

Cited by 79 publications

(197 citation statements)

References 18 publications

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“…Parietal, posterolateral (5 occipital) process: (0) nearly vertical; (1) anteriorly inclined greater than 45u ( fig. 17) (modified from Heckert and Lucas, 1999).…”

Section: (New)mentioning

confidence: 99%

“…Premaxilla, teeth: (0) present along entire length of the premaxilla; (1) absent in the anterior portion of the premaxilla (modified from Heckert et al, 1999;Parker, 2007).…”

Section: Allosaurus Fragilis Marsh 1877mentioning

confidence: 99%

“…Jugal, long axis of the body: (0) nearly horizontal; (1) anterodorsally inclined ( fig. 17) (modified from Heckert and Lucas, 1999;Parker, 2007).…”

Section: Convex (Fig 19) (New)mentioning

confidence: 99%

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

Nesbitt

2011

Bulletin of the American Museum of Natural History

745

2,561

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“…Parietal, posterolateral (5 occipital) process: (0) nearly vertical; (1) anteriorly inclined greater than 45u ( fig. 17) (modified from Heckert and Lucas, 1999).…”

Section: (New)mentioning

confidence: 99%

“…Premaxilla, teeth: (0) present along entire length of the premaxilla; (1) absent in the anterior portion of the premaxilla (modified from Heckert et al, 1999;Parker, 2007).…”

Section: Allosaurus Fragilis Marsh 1877mentioning

confidence: 99%

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

Nesbitt

2011

Bulletin of the American Museum of Natural History

745

2,561

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“…Aetosaurs (also known as Stagonolepididae) are a group of quadrupedal, armoured herbivores (and possibly omnivores) known globally from the Upper Triassic. They are diagnosed by numerous synapomorphies (Parrish 1994;Heckert et al 1996;Heckert & Lucas 1999Harris et al 2003;Parker 2007). Many studies advocate a position more derived than phytosaurs, but less derived than crocodylomorphs and 'rauisuchians' (Gauthier 1986;Benton 1999;Nesbitt 2003.…”

Section: Crurotarsimentioning

confidence: 99%

“…Therefore, proposed synapomorphies of these groups were reviewed and critically assessed, and all characters showing clear variability in other archosaur taxa were included. Lists of synapomorphies considered for each ingroup include: Aetosauria (Parrish 1994;Heckert & Lucas 1999;Parker 2007), Crocodylomorpha Sues et al 2003), Ornithischia ), Ornithosuchidae ), Phytosauria , Pterosauria ) and Saurischia .…”

Section: Ingroup Selectionmentioning

confidence: 99%

The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)

Brusatte

Benton

Desojo

et al. 2010

Journal of Systematic Palaeontology

217

318

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Crown group Archosauria, which includes birds, dinosaurs, crocodylomorphs, and several extinct Mesozoic groups, is a primary division of the vertebrate tree of life. However, the higher-level phylogenetic relationships within Archosauria are poorly resolved and controversial, despite years of study. The phylogeny of crocodile-line archosaurs (Crurotarsi) is particularly contentious, and has been plagued by problematic taxon and character sampling. Recent discoveries and renewed focus on archosaur anatomy enable the compilation of a new dataset, which assimilates and standardizes character data pertinent to higher-level archosaur phylogeny, and is scored across the largest group of taxa yet analysed. This dataset includes 47 new characters (25% of total) and eight taxa that have yet to be included in an analysis, and total taxonomic sampling is more than twice that of any previous study. This analysis produces a well-resolved phylogeny, which recovers mostly traditional relationships within Avemetatarsalia, places Phytosauria as a basal crurotarsan clade, finds a close relationship between Aetosauria and Crocodylomorpha, and recovers a monophyletic Rauisuchia comprised of two major subclades. Support values are low, suggesting rampant homoplasy and missing data within Archosauria, but the phylogeny is highly congruent with stratigraphy. Comparison with alternative analyses identifies numerous scoring differences, but indicates that character sampling is the main source of incongruence. The phylogeny implies major missing lineages in the Early Triassic and may support a Carnian-Norian extinction event.

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Disparate Growth Strategies within Aetosauria: Novel Histologic Data from the Aetosaur Coahomasuchus chathamensis

Hoffman

Heckert

Zanno

2018

The Anatomical Record

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Aetosaurs comprise a clade of quadrupedal, armored, omnivores to herbivores that lived across much of the supercontinent of Pangea during the Late Triassic. Their relative abundance in many units, and the rarity of other Triassic herbivores, points to them as key components of Late Triassic ecosystems. Debate persists about whether they were growing more or less slowly when compared to extant crocodylians, and bone histology is sparsely sampled within the group. We undertook a histological examination of Coahomasuchus chathamensis to address its ontogenetic trajectory and characterize its histology. We sampled a paramedian osteoderm from the holotype specimen, as well as five osteoderms (two paramedian, one lateral, and two of uncertain position) and two incomplete limb bones (radius and fibula), from referred specimens discovered at the type locality. Using these we estimated specimen ages with lines of arrested growth (LAGs) to determine that the study individuals reached from 2 to 7 years old. All of the sampled elements contained woven-fibered bone with extensive vasculature within the internal cortex. In some specimens, more poorly vascularized, parallel-fibered bone is evident externally. The holotype of C. chathamensis represents a juvenile individual, and raises the possibility that the holotype of C. kahleorum is a juvenile as well, complicating aetosaur systematics and diversity. When compared to aetosaurs of similar size, it is clear that C. chathamensis was growing comparatively rapidly, about 3 times the rate of similarly sized specimens of Aetosauroides scagliai from Argentina. This discovery reveals the presence of disparate growth strategies within Aetosauria. Anat Rec, 302:1504-

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A new aetosaur (Reptilia: Archosauria) from the Upper Triassic of Texas and the phylogeny of aetosaurs

Cited by 79 publications

References 18 publications

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

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

The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)

Disparate Growth Strategies within Aetosauria: Novel Histologic Data from the Aetosaur Coahomasuchus chathamensis

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