The discovery of large, complex, internal canals within the rostra of fossil reptiles has been li... more The discovery of large, complex, internal canals within the rostra of fossil reptiles has been linked with an enhanced tactile function utilised in an aquatic context, so far in pliosaurids, the Cretaceous theropod Spinosaurus, and the related spinosaurid Baryonyx. Here, we report the presence of a complex network of large, laterally situated, anastomosing channels, discovered via micro-focus computed tomography (μCT), in the premaxilla and maxilla of Neovenator, a mid-sized allosauroid theropod from the Early Cretaceous of the UK. We identify these channels as neurovascular canals, that include parts of the trigeminal nerve; many branches of this complex terminate on the external surfaces of the premaxilla and maxilla where they are associated with foramina. Neovenator is universally regarded as a 'typical' terrestrial, predatory theropod, and there are no indications that it was aquatic, amphibious, or unusual with respect to the ecology or behaviour predicted for allosauroids. Accordingly, we propose that enlarged neurovascular facial canals shouldn't be used to exclusively support a model of aquatic foraging in theropods and argue instead that an enhanced degree of facial sensitivity may have been linked with any number of alternative behavioural adaptations, among them defleshing behaviour, nest selection/maintenance or social interaction. Neovenator salerii is an allosauroid theropod from the Wessex Formation of the Isle of Wight, UK (Barremian, Early Cretaceous) 1, 2 , known from a partial skeleton (Museum of Isle of Wight Geology (MIWG) 6348) that comprises extensive cranial, axial, and appendicular material preserved in excellent three-dimensional condition. Neovenator is a member of the tetanuran clade Allosauroidea, as evidenced by a suite of cranial and postcranial characters 2–5. Within Allosauroidea, recent work identifies it a basal member of Neovenatoridae 6. A deep, laterally compressed (oreinirostral) skull, large, ziphodont teeth, and a facial and mandibular skeleton considered typical for large, predatory theropods indicate that Neovenator was a terrestrial predator that attacked and dispatched vertebrate prey in a manner typical for allosauroids. Neovenator has been assumed to have been an apex terrestrial predator, like its carcharodontosaurian close relatives 7. Analysis of the feeding dynamics of the closely-related Allosaurus fragilis indicate powerful ventroflexive angular acceleration of the skull, coupled with minimal shake feeding 8. Minimal tooth-to-bone contact and the targeting of smaller/juvenile individuals are also predicted 9. There are no indications that Neovenator was unusual in ecology or prey choice with respect to other allosauroids and it is assumed to have been a predator of ornithopods and other mid-sized dinosaurs, a hypothesis supported by bite marks on an associated specimen of the iguanodontian Mantellisaurus atherfieldensis. The osteology of Neovenator is well-understood 2. However, we were intrigued by enlarged foramina present on both the lateral surface of the premaxilla, occasionally set within shallow grooves 2 , and on the anterior ramus of the maxilla and hypothesised that they might be indicative of a rostral neuroanatomy similar to that reported in spinosaurids 10 , and more recently, tyrannosaurids 11. Complex neuroanatomical systems present in the rostra of many vertebrates have been associated with a function in prey detection. However, poor preservation typically means that they are not sufficiently well-preserved to allow detailed examination 12. Mini-focus medical CT imaging of the Cretaceous spinosaurid Spinosaurus aegyptiacus was previously employed to investigate the internal
The discovery of large, complex, internal canals within the rostra of fossil reptiles has been li... more The discovery of large, complex, internal canals within the rostra of fossil reptiles has been linked with an enhanced tactile function utilised in an aquatic context, so far in pliosaurids, the Cretaceous theropod Spinosaurus, and the related spinosaurid Baryonyx. Here, we report the presence of a complex network of large, laterally situated, anastomosing channels, discovered via micro-focus computed tomography (μCT), in the premaxilla and maxilla of Neovenator, a mid-sized allosauroid theropod from the Early Cretaceous of the UK. We identify these channels as neurovascular canals, that include parts of the trigeminal nerve; many branches of this complex terminate on the external surfaces of the premaxilla and maxilla where they are associated with foramina. Neovenator is universally regarded as a 'typical' terrestrial, predatory theropod, and there are no indications that it was aquatic, amphibious, or unusual with respect to the ecology or behaviour predicted for allosauroids. Accordingly, we propose that enlarged neurovascular facial canals shouldn't be used to exclusively support a model of aquatic foraging in theropods and argue instead that an enhanced degree of facial sensitivity may have been linked with any number of alternative behavioural adaptations, among them defleshing behaviour, nest selection/maintenance or social interaction. Neovenator salerii is an allosauroid theropod from the Wessex Formation of the Isle of Wight, UK (Barremian, Early Cretaceous) 1, 2 , known from a partial skeleton (Museum of Isle of Wight Geology (MIWG) 6348) that comprises extensive cranial, axial, and appendicular material preserved in excellent three-dimensional condition. Neovenator is a member of the tetanuran clade Allosauroidea, as evidenced by a suite of cranial and postcranial characters 2–5. Within Allosauroidea, recent work identifies it a basal member of Neovenatoridae 6. A deep, laterally compressed (oreinirostral) skull, large, ziphodont teeth, and a facial and mandibular skeleton considered typical for large, predatory theropods indicate that Neovenator was a terrestrial predator that attacked and dispatched vertebrate prey in a manner typical for allosauroids. Neovenator has been assumed to have been an apex terrestrial predator, like its carcharodontosaurian close relatives 7. Analysis of the feeding dynamics of the closely-related Allosaurus fragilis indicate powerful ventroflexive angular acceleration of the skull, coupled with minimal shake feeding 8. Minimal tooth-to-bone contact and the targeting of smaller/juvenile individuals are also predicted 9. There are no indications that Neovenator was unusual in ecology or prey choice with respect to other allosauroids and it is assumed to have been a predator of ornithopods and other mid-sized dinosaurs, a hypothesis supported by bite marks on an associated specimen of the iguanodontian Mantellisaurus atherfieldensis. The osteology of Neovenator is well-understood 2. However, we were intrigued by enlarged foramina present on both the lateral surface of the premaxilla, occasionally set within shallow grooves 2 , and on the anterior ramus of the maxilla and hypothesised that they might be indicative of a rostral neuroanatomy similar to that reported in spinosaurids 10 , and more recently, tyrannosaurids 11. Complex neuroanatomical systems present in the rostra of many vertebrates have been associated with a function in prey detection. However, poor preservation typically means that they are not sufficiently well-preserved to allow detailed examination 12. Mini-focus medical CT imaging of the Cretaceous spinosaurid Spinosaurus aegyptiacus was previously employed to investigate the internal
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