Stimulus discrimination and surface wave source localization in Crocodilians

Grap, Nadja J.; Machts, Tobias; Essert, Sarah M.; Bleckmann, Horst

doi:10.1016/j.zool.2020.125743

Cited by 11 publications

(14 citation statements)

References 28 publications

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“…In the aquatic environment, the crocodylian trigeminal nerve mediates discrimination between fine changes in wave frequency (i.e., 1.2 Hz) and distance estimation from a single wave (Grap, Matchts, Essert, & Bleckmann, 2020). This behavior requires high sensitivity, made possible by high receptor density (Dehnhardt & Kaminski, 1995; Nicolelis, Lin, & Chapin, 1997).…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, there is likely an increase in trigeminal sensitivity at the end of the crocodylian rostrum. Additionally, lower branch counts across the length of the C. johnstoni canals (Figure 5) may indicate lower sensitivity than other species, whereas higher branch counts across the length of the Alligator canals may indicate higher sensitivity than other species, but stimulus discrimination testing across species (e.g., Grap et al, 2020) would be necessary to confirm differences in performance.…”

Section: Discussionmentioning

confidence: 99%

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Quantifying neurovascular canal branching patterns reveals a shared crocodylian arrangement

Lessner

2020

Journal of Morphology

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Highly branched dendritic structures are common in nature and often difficult to quantify and therefore compare. Cranial neurovascular canals, examples of such structures, are osteological correlates for somatosensory systems and have been explored only qualitatively. Adaptations of traditional stream‐ordering methods are applied to representative structures derived from computed tomography‐scan data. Applying these methods to crocodylian taxa, this clade demonstrates a shared branching pattern and exemplifies the comparative utility of these methods. Additionally, this pattern corresponds with current understanding of crocodylian sensory abilities and behaviors. The method is applicable to many taxa and anatomical structures and provides evidence for morphology‐based hypotheses of sensory and physiological evolution.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Quantifying neurovascular canal branching patterns reveals a shared crocodylian arrangement

Lessner

2020

Journal of Morphology

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“…The presence of a unique trigeminal-innervated, highly sensitive mechanoreceptive system in the crocodilian face (integumentary sensory organs-ISOs) is a possible reason for this Vgang enlargement (George & Holliday, 2013). This sensory system is important for the crocodilian semiaquatic lifestyle as it can detect pressure changes in the surrounding water (Di-Poï & Milinkovitch, 2013;Grap, Machts, Essert, & Bleckmann, 2020;Leitch & Catania, 2012;Soares, 2002;von During, 1973;von During, 1974;von During & Miller, 1979). Therefore, a large Vfossa and mmf would imply the presence of a large Vgang and the presence of enhanced face sensitivity, which is only known in semiaquatic taxa (George & Holliday, 2013).…”

Section: Trigeminal Fossa and Facial Sensitivitymentioning

confidence: 99%

Paleoneurology of Baurusuchus (Crocodyliformes: Baurusuchidae), ontogenetic variation, brain size, and sensorial implications

Dumont

Santucci

Andrade

et al. 2020

The Anatomical Record

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Knowledge on crocodyliform paleoneurology has significantly improved with development of computed tomography. However, studies so far have been able to reconstruct brain endocasts based only on single specimens for each taxon. Here for the first time, we reconstructed brain endocasts for multiple fossil specimens of the same crocodyliform taxon (Baurusuchus), consisting of complete skulls of two medium sized specimens, one large adult, and a late juvenile. In addition, we were able to reconstruct the inner ear anatomy of a fragmentary skull using microtomography. We present estimates of brain size using simple models, based on modern Crocodylia, able to adapt brain to endocranial cavity ratios to expected ontogenetic variation instead of using fixed ratios. We also analyzed relative brain sizes, olfactory ratios, facial sensation, alert head posture, best hearing frequencies, and hearing range. The calculated endocranial volumes showed that they can be greatly altered by taphonomic processes, altering both total and partial endocranial volumes. Reconstructed endocasts are compatible with different degrees of occupation along the endocranial cavity and some of their characteristics might be useful as phylogenetic characters. The relative brain size of Baurusuchus seems to be small in comparison to modern crocodilians. Sensorial abilities were somewhat similar to modern crocodilians and hearing ranges and best mean frequencies remarkably similar to modern taxa, whereas olfactory ratio values are a little higher. Differing from its modern relatives, Baurusuchus hypothesized alert head posture is compatible with a terrestrial habit.

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“…Specimens and prediction results (fossil specimens shaded) 1)Martin and Coetzee (2004),Martin (2007). (2)Leitch and Catania (2012), Di-Poï andMilinkovitch (2013),Grap et al (2020). (3)Cunningham et al (2013).…”

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confidence: 99%

Ecomorphological patterns in trigeminal canal branching among sauropsids reveal sensory shift in suchians

et al. 2023

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The vertebrate trigeminal nerve is the primary mediator of somatosensory information from nerve endings across the face, extending nerve branches through bony canals in the face and mandibles, terminating in sensory receptors. Reptiles evolved several extreme forms of cranial somatosensation in which enhanced trigeminal tissues are present in species engaging in unique mechanosensory behaviors. However, morphology varies by clade and ecology among reptiles. Few lineages approach the extreme degree of tactile somatosensation possessed by crocodylians, the only remaining members of a clade that underwent an ecological transition from the terrestrial to semiaquatic habitat, also evolving a specialized trigeminal system. It remains to be understood how trigeminal osteological correlates inform how adaptations for enhanced cranial sensation evolved in crocodylians. Here we identify an increase in sensory abilities in Early Jurassic crocodylomorphs, preceding the transitions to a semiaquatic habitat. Through quantification of trigeminal neurovascular canal branching patterns in an extant phylogenetic bracket we quantify and identify morphologies associated with sensory behaviors in representative fossil taxa, we find stepwise progression of increasing neurovascular canal density, complexity, and distribution from the primitive archosaurian to the derived crocodilian condition. Model‐based inferences of sensory ecologies tested on quantified morphologies of extant taxa with known sensory behaviors indicate a parallel increase in sensory abilities among pseudosuchians. These findings establish patterns of reptile trigeminal ecomorphology, revealing evolutionary patterns of somatosensory ecology.

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Stimulus discrimination and surface wave source localization in Crocodilians

Cited by 11 publications

References 28 publications

Quantifying neurovascular canal branching patterns reveals a shared crocodylian arrangement

Quantifying neurovascular canal branching patterns reveals a shared crocodylian arrangement

Paleoneurology of Baurusuchus (Crocodyliformes: Baurusuchidae), ontogenetic variation, brain size, and sensorial implications

Ecomorphological patterns in trigeminal canal branching among sauropsids reveal sensory shift in suchians

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