Inner skull cavities of the basal eusuchian Lohuecosuchus megadontos (Upper Cretaceous, Spain) and neurosensorial implications

Serrano-Martínez, Alejandro; Knoll, Fabien; Narváez, Iván; Lautenschlager, Stephan

doi:10.1016/j.cretres.2018.08.016

Cited by 15 publications

(61 citation statements)

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“…Erickson 26 noted that Champsosaurus may have possessed a well-developed sense of smell due to the pronounced olfactory chambers of the nasal passages, a conclusion supported here by the prominent olfactory chambers and olfactory duct of CMN 8920 (Fig. 8) that appear comparable in proportional size (relative to the total length of the skull and brain, respectively) to those of modern crocodiles 4 and gharials 71 . He also stated that a well-developed sense of smell in Champsosaurus would be inconsistent with its aquatic habits, because detecting airborne odours would have had little importance for detecting food, but Erickson 26 did not consider other advantages of high olfactory acuity.…”

Section: Resultssupporting

confidence: 57%

The internal cranial anatomy of Champsosaurus (Choristodera: Champsosauridae): Implications for neurosensory function

Dudgeon

Maddin

Evans

et al. 2020

Sci Rep

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Although isolated Champsosaurus remains are common in Upper cretaceous sediments of north America, the braincase of these animals is enigmatic due to the fragility of their skulls. Here, two wellpreserved specimens of Champsosaurus (CMN 8920 and CMN 8919) are CT scanned to describe their neurosensory structures and infer sensory capability. the anterior portion of the braincase was poorly ossified and thus does not permit visualization of a complete endocast; however, impressions of the olfactory stalks indicate that they were elongate and likely facilitated good olfaction. the posterior portion of the braincase is ossified and morphologically similar to that of other extinct diapsids. The absence of an otic notch and an expansion of the pars inferior of the inner ear suggests Champsosaurus was limited to detecting low frequency sounds. comparison of the shapes of semicircular canals with lepidosaurs and archosauromorphs demonstrates that the semicircular canals of Champsosaurus are most similar to those of aquatic reptiles, suggesting that Champsosaurus was well adapted for sensing movement in an aquatic environment. this analysis also demonstrates that birds, non-avian archosauromorphs, and lepidosaurs possess significantly different canal morphologies, and represents the first morphometric analysis of semicircular canals across Diapsida.Palaeoneurology, the study of the brain in the fossil record and how it has changed through time 1 , provides some of the best evidence for how extinct animals behaved and interacted with their environment. The behaviour and sensory abilities of extinct taxa are inferred based on the morphology of regions of the brain that are directly responsible for processing sensory information and forming behaviour. Other neural structures are often included in palaeoneurological studies, such as the cranial nerves and membranous labyrinth, which transmit sensory and motor information to and from the brain, and facilitate the sensation of movement and orientation, respectively. Estimations of sensory ability and behaviour based on the morphology of the brain are made possible by the principle of proper mass, which states that the size of a brain region dedicated to a specific function is directly correlated with the amount of processing power required to complete that function 2 . Therefore, regions of the brain that require more processing power tend to be larger to accommodate a greater number of neurons.This correlation allows hypotheses to be made about the sensory ability of extinct animals based on the morphology of the brain; 3,4 however, the brain endocast is not a perfect reflection of the brain in life, as it also represents other soft-tissue structures housed within the endocranial cavity that did not fossilize, such as the dura matter and vascular tissue 5 . Despite this, a description of the endocranial cavity of an extinct animal provides data that can be used to infer its neurosensory capabilities by comparison to closely related extant taxa, which allows for the formation o...

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Section: Resultssupporting

confidence: 57%

The internal cranial anatomy of Champsosaurus (Choristodera: Champsosauridae): Implications for neurosensory function

Dudgeon

Maddin

Evans

et al. 2020

Sci Rep

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“…2017; Serrano‐Martínez et al . 2019a). Nevertheless, the analyses of fossil specimens have improved our knowledge of the inner skull cavities of extinct eusuchians, such as the basal eusuchians Aegisuchus witmeri (Holliday & Gardner 2012), Allodaposuchus hulki (Blanco et al .…”

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confidence: 99%

“…2015) and Lohuecosuchus megadontos (Serrano‐Martínez et al . 2019a), the alligatoroids Mourasuchus nativus (Bona et al . 2013) and Diplocynodon tormis (Serrano‐Martínez et al .…”

mentioning

confidence: 99%

Neuroanatomical and neurosensorial analysis of the Late Cretaceous basal eusuchian Agaresuchus fontisensis (Cuenca, Spain)

Serrano-Martínez

Knoll

Narváez

et al. 2020

Papers in Palaeontology

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Agaresuchus fontisensis is an allodaposuchid crocodile from the Campanian–Maastrichtian (Late Cretaceous) of Lo Hueco (Cuenca, Spain). Allodaposuchidae is a clade of European basal eusuchians, which is considered a part of the stem group of Crocodylia. The holotype and paratype skulls of Agaresuchus fontisensis were scanned on computed tomography and their internal cavities, including those of the brain, nerves and blood vessels, as well as the paratympanic sinus system and the paranasal sinuses, digitally reconstructed. The cranial endocast and pneumatic sinuses were then compared with those of other crocodyliforms. The neuroanatomy of Agaresuchus fontisensis resembles those of other mesoeucrocodylians, sharing some morphological traits with extant crocodiles. The neurosensorial and cognitive capabilities inferred from the inner skull cavity reconstructions of Agaresuchus fontisensis are similar to those of other eusuchians. The olfactory acuity of Agaresuchus fontisensis is low by crocodylian standards, closer to that of the alligatoroids rather than to that of the crocodyloids. Its visual acuity is similar to that of Lohuecosuchus megadontos, a sympatric allodaposuchid also found in the fossil site of Lo Hueco.

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“…) and the basal euschian Lohuecosuchus megadontos (Serrano‐Martínez et al . ), for which auditory acuity has also been estimated.…”

Section: Discussionmentioning

confidence: 99%

“…) and with the basal eusuchian Lohuecosuchus megadontos (Serrano‐Martínez et al . ). As individuals can typically only hear within their own vocal range, estimations of auditory acuity can be informative regarding vocality (Narins et al .…”

Section: Methodsmentioning

confidence: 97%

Endocranial anatomy and life habits of the Early Triassic archosauriform Proterosuchus fergusi

et al. 2019

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Proterosuchids are an important group of carnivorous basal archosauriforms characterized by a bizarre and enigmatic downturned premaxilla that overhangs the lower jaw. They are particularly significant because they radiated in the immediate aftermath of the Permian–Triassic mass extinction and represent one of the best known ‘disaster taxa’ following that event. While traditionally considered to be semi‐aquatic, recent histological studies and geological data have suggested that it is more likely that they inhabited terrestrial environments. By using computed tomographic (CT) data, we virtually reconstruct the brain endocast and endosseous labyrinths of two adult specimens of Proterosuchus fergusi from the earliest Triassic of South Africa, in an attempt to understand its life habits within the context of basal archosauriform evolution. Endocasts reveal that the brain cavity is tubular in shape and the endosseous labyrinths are highly pyramidal. The angle of the lateral semicircular canal suggests that P. fergusi naturally held its head upwards ~17°, while the length of the cochlear duct suggests its auditory abilities were specialized towards low‐frequency sounds. Furthermore, beam theory analysis suggests that the rostrum of P. fergusi is highly resistant to both bending and torsion when compared to modern crocodilians, although this resistance is neither enhanced nor reduced by the overhanging premaxilla. Comparative anatomical analyses suggest P. fergusi was probably a semi‐aquatic, generalist apex predator capable of surviving the harsh environmental perturbations of the Early Triassic.

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Inner skull cavities of the basal eusuchian Lohuecosuchus megadontos (Upper Cretaceous, Spain) and neurosensorial implications

Cited by 15 publications

References 50 publications

The internal cranial anatomy of Champsosaurus (Choristodera: Champsosauridae): Implications for neurosensory function

The internal cranial anatomy of Champsosaurus (Choristodera: Champsosauridae): Implications for neurosensory function

Neuroanatomical and neurosensorial analysis of the Late Cretaceous basal eusuchian Agaresuchus fontisensis (Cuenca, Spain)

Endocranial anatomy and life habits of the Early Triassic archosauriform Proterosuchus fergusi

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