The first braincase of the basal aetosaur <i>Aetosauroides scagliai</i> (Archosauria: Pseudosuchia) from the Upper Triassic of Brazil

Neto, Voltaire D. Paes; Desojo, Julia Brenda; Brust, Ana Carolina Biacchi; Ribeiro, Ana María; Schultz, César Leandro; Soares, Marina Bento

doi:10.1080/02724634.2021.1928681

Cited by 11 publications

(27 citation statements)

References 57 publications

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“…Although the aetosaur Calyptosuchus wellesi is also known from the Placerias Quarry, it is not possible to refer any of the three UCMP braincases under consideration here to that species because the holotype of C. wellesi has no cranial elements, and therefore there are no overlapping materials to compare. However, there are two braincases in the UCMP collections (UCMP 27414 and 27419) that differ from the morphology of Desmatosuchus according to Parker (2018), and perhaps a third one (UCMP 27409) which in turn might correspond to C. wellesi (Paes Neto et al, 2021). The morphology of these braincases differs from that of Desmatosuchus because the basipterygoid processes are strongly projected anterolaterally with a well‐delimited pit between these processes.…”

Section: Methodsmentioning

confidence: 99%

“…Desmatosuchus smalli is differentiated by having parietals without a transverse sulcus (only a slight depression on that region), a shallow medial pharyngeal recess that is confluent anteriorly with a depressed area that fades at the level of the basipterygoid processes, a sizeable gap between basal tubera and basipterygoid processes, and exoccipitals that do not meet at the midline (following Parker, 2005aParker, , 2005bPaes Neto et al, 2021). Along with UCMP 27410, the isolated braincases UCMP 27418, 27421, and 27345 can be referred to D. smalli.…”

Section: New Materials Of Desmatosuchus From the Ucmp Collectionsmentioning

confidence: 99%

“…However, little is still known about endocranial diversity within most pseudosuchian lineages. In the particular case of aetosaurs, the braincase morphology of several species is reasonably well known, such as Stagonolepis olenkae , Neoaetosauroides engaeus , Scutarx deltatylus , Longosuchus meadei , Desmatosuchus spurensis , D. smalli , and Aetosauroides scagliai (Desojo & Báez, 2007; Gower & Walker, 2002; Paes Neto et al, 2021; Parker, 2005a, 2005b; Parker, 2016b; Parrish, 1994; Small, 2002; Sulej, 2010). Nonetheless, very few paleoneurological studies have been made on this clade, with the only published studies being the endocranial reconstructions of Desmatosuchus spurensis (Case, 1921) and Neoaetosauroides engaeus (von Baczko et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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New digital braincase endocasts of two species of Desmatosuchus and neurocranial diversity within Aetosauria (Archosauria: Pseudosuchia)

Baczko

Desojo

Gower

et al. 2021

The Anatomical Record

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In the present contribution we revise, figure, and redescribe several isolated braincases of the iconic aetosaur Desmatosuchus from the Placerias Quarry locality, Chinle Formation, Arizona, United States. The detailed study of the isolated braincases from the UCMP collection allowed us to assign them at the species-level and recognize two species of Desmatosuchus for the Placerias Quarry: D. spurensis and D. smalli. The former can be distinguished from the latter by the presence of a transverse sulcus on the parietals, deep median pharyngeal recess on the basisphenoid, almost no gap between the basal tubera and the basipterygoid processes, and the exoccipitals meeting at the midline. The presence of D. smalli at the Placerias Quarry has not been previously reported. Based on the braincases UCMP 27408, 27410, 27407, three new brain endocasts were developed through CT scan images, reconstructing the most complete endocranial casts known for an aetosaur, including the encephalon, cranial nerves, inner ear, and endocranial vasculature. The cranial endocasts also exhibited some differences between both species of Desmatosuchus, with D. spurensis having a distinguishable dural expansion and markedly asymmetric anterior and posterior semicircular canals of the labyrinth. Additionally, the combination of osteological features and the endocranial casts allowed us to identify and discuss the presence of an ossified orbitosphenoid on the anteriormost region of the braincase among aetosaurs. Furthermore, we were able to reinterpret some of the observations made by previous authors on the endocast of the holotype of Desmatosuchus spurensis (UMMP VP 7476) and provide some insight into their neurosensory capabilities.

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Section: Methodsmentioning

confidence: 99%

Section: New Materials Of Desmatosuchus From the Ucmp Collectionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New digital braincase endocasts of two species of Desmatosuchus and neurocranial diversity within Aetosauria (Archosauria: Pseudosuchia)

Baczko

Desojo

Gower

et al. 2021

The Anatomical Record

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“…In phylogenetic analyses, A. scagliai has been recovered as either the sister-taxon of Stagonolepis robertsoni Agassiz, 1844(e.g., Parrish, 1994Heckert et al, 1996;Heckert and Lucas, 1999;Harris et al, 2003;Parker, 2007) or as the earliest-diverging aetosaur (i.e., the only non-stagonolepidid aetosaur; e.g., Desojo et al, 2012;Heckert et al, 2015;Schoch and Desojo, 2016;Parker, 2016a;Brust et al, 2018;Hoffman et al, 2018;Reyes et al, 2021). Recent research on A. scagliai has provided a better understanding of its intraspecific variation Taborda et al, 2013;Taborda et al, 2015;Paes Neto et al, 2021b) and cranial osteology (Brust et al, 2018;Paes Neto et al, 2021a). These and other studies (e.g., Desojo, 2005) have firmly established the Gondwanan A. scagliai as a valid taxon, distinct from the Laurasian S. robertsoni and Calyptosuchus wellesi Ballew, 1985 (contra Heckert andLucas, 2000;Lucas and Heckert, 2001;Heckert and Lucas, 2002), a status recognized in most recent work on the group (e.g., Desojo et al, 2012Desojo et al, , 2013Robertoda-Silva et al, 2014;Heckert et al, 2015;Parker, 2016a,b;Schoch and Desojo, 2016;Ezcurra et al, 2017;Brust et al, 2018;Hoffman et al, 2018;Parker, 2018a,b;Desojo et al, 2020a,b;Marsh et al, 2020;…”

Section: Introductionmentioning

confidence: 99%

“…This specimen is the aetosaur mentioned for the Piche site in the biostratigraphic study of Langer et al (2007); (6) ULBRAPV003T, a small specimen with almost complete preservation of the axial and appendicular skeleton (see Roberto-da-Silva et al, 2013). This is the holotype of 'Polesinesuchus aurelioi', now considered to represent the most immature specimen known of A. scagliai (see Paes Neto et al, 2021a). Horizon and locality.…”

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confidence: 97%

Skull osteology of Aetosauroides scagliai Casamiquela, 1960 (Archosauria: Aetosauria) from the Late Triassic of Brazil: New insights into the paleobiology of aetosaurs

Neto

Desojo²,

Brust³

et al. 2021

Palaeontol Electron

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Aetosauroides scagliai, from the Ischigualasto Formation of Argentina and Santa Maria Supersequence of Brazil (Carnian-Norian), is one of the oldest members of Aetosauria, a diverse clade of armored crocodile-line archosaurs. Aetosauroides scagliai differs from other aetosaurs in having the maxilla excluded from the margin of the external nares, the length/width ratio of the postzygapophyses ≤ 0.75, and other features that place it as one of the earliest-diverging members of the clade. In this paper we provide a detailed description of the skull of A. scagliai based on a new Brazilian specimen, revealing that it lacks a pneumatic cavity on the medial surface of the maxilla and further differs from all other known aetosaurs by the presence of ≥ 12 dentary teeth. However, contra previous studies, the elongated posterior process of the jugal does articulate ventrally with the quadratojugal in A. scagliai, forming the posteroventral corner of the skull as in all other aetosaurs. Aetosauroides scagliai exhibits some characters typical of predatory archosaurs (like the recurved ziphodont teeth and mandibular articulation at the level of the tooth row), but was probably an omnivore, as it also shares several probable adaptations for herbivory with aetosaurs generally (i.e., edentulous anterior premaxilla and dentary) and stagonolepidoids specifically (e.g., shovel-shaped snout). This suggests that there was greater trophic diversity in this clade than usually recognized, at least early in their evolutionary history.

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Paleoneurology and neuroanatomical notes on the South American “rauisuchian” Saurosuchus galilei from the Ischigualasto formation, San Juan, Argentina

von Baczko,

Cardillo,

Ulloa‐Guaiquin

et al. 2023

The Anatomical Record

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Non‐crocodylomorph loricatans, traditionally known as “rauisuchians,” are considered as the top predators of the Triassic continental faunas that reigned before the emergence of the well‐known theropod dinosaurs. In particular, Saurosuchus galilei is a large quadrupedal prestosuchid loricatan found in the Ischigualasto Formation from northwestern Argentina. Here, we reevaluated the braincase of S. galilei and present the first paleoneurological study based on the partial natural casts of the holotype and the digital cranial endocast of the referred specimen PVSJ 32. The braincase of S. galilei was here reinterpreted, identifying the sutures of the supraoccipital, otoccipital, basioccipital, parabasisphenoid, prootic, and laterosphenoid. A unique feature identified in the braincase of S. galilei is the presence of deep paracondylar recesses associated with pharyngotympanic pneumaticity, which has not been identified in any other “rauisuchians” so far. Most of the structures of the encephalon were recognized in the cranial endocast and natural casts including cranial nerves V–XII, olfactory bulbs, main blood vessels and sinuses, and inner ear. These structures allowed us to quantify some of its sensorial capacities and recognize that S. galilei had an enhanced olfactory acuity, with coefficients higher than those expected for its body size, a condition previously observed in living crocodilians and tyrannosaurid dinosaurs. An improved sense of smell might have allowed Saurosuchus to track its prey from long distances and compensate for the poorer development of its other senses like vision and balance.

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The first braincase of the basal aetosaur Aetosauroides scagliai (Archosauria: Pseudosuchia) from the Upper Triassic of Brazil

Cited by 11 publications

References 57 publications

New digital braincase endocasts of two species of Desmatosuchus and neurocranial diversity within Aetosauria (Archosauria: Pseudosuchia)

New digital braincase endocasts of two species of Desmatosuchus and neurocranial diversity within Aetosauria (Archosauria: Pseudosuchia)

Skull osteology of Aetosauroides scagliai Casamiquela, 1960 (Archosauria: Aetosauria) from the Late Triassic of Brazil: New insights into the paleobiology of aetosaurs

Paleoneurology and neuroanatomical notes on the South American “rauisuchian” Saurosuchus galilei from the Ischigualasto formation, San Juan, Argentina

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