Istiorachis macarthurae: A new species of Iguanodontian Dinosaur from the Early Cretaceous Wessex Formation of the Isle of Wight.

The Iguanodontians were a highly successful group of Ornithischian Dinosaurs, which included groups such as the Dryosaurids, Iguanodonts, and Hadrosaurs. The oldest known Iguanodontian is Callovosaurus leedsi, a Dryosaurid from the Middle Jurassic Oxford Clay Formation of England, while by the End of the Cretaceous they were the most numerous group of Herbivorous Dinosaurs in Laurasia. The Iguanodontians were a relatively minor part of Late Jurassic faunas, but underwent a significant evolutionary radiation in the Early Cretaceous, becoming a numerous and morphologically diverse group, which they remained throughout the Cretaceous Period.

In a paper published in the journal Papers in Palaeontology on 21 August 2025, Jeremy Lockwood of the Fossil Reptiles, Amphibians and Birds Section at the Natural History Museum, and the School of the Environment and Life Sciences at the University of Portsmouth, David Martill, also of the School of the Environment and Life Sciences at the University of Portsmouth, and Sussanah Maidment, also of the Fossil Reptiles, Amphibians and Birds Section at the Natural History Museum, describe a new species of Iguanodontian Dinosaur from the Early Cretaceous Wessex Formation of the Isle of Wight.

The new species is named Istiorachis macarthurae, where 'Istiorachis' means 'sail-spine' in reference to the long neural spines on the vertebrae of the species, which may have given it a 'sail-backed' appearance, and 'macarthurae' honours  Dame Ellen MacArthur, an English sailor who in 2005 set a world record forthe fastest solo non-stop voyage around the world on her first attempt and who also founded the Ellen MacArthur Cancer Trust for young people on the Isle of Wight. It is described from a single, partial specimen recovered from the 1.5 m thick 'Black Band' which outcrops about 100 m to the east of Grange Chine (a chine on the Isle of White is a steep-sided gorge cut into a cliff made from a soft sediment by a stream immediately before reaching the sea). This 'Black Band' overlies the Grange Chine Sandstone within the Wessex Formation.

Locality and stratigraphy of Istiorachis macarthurae. (A) Generalised stratigraphic log and  schematic lithological logs of Wealden Group exposure between Sudmoor and Atherfield on the Isle of Wight,  showing excavation sites of the holotypes of the new Dinosaur (MIWG 6643), Brighstoneus simmondsi (MIWG 6344) and Mantellisaurus atherfieldensis (NHMUK PV R 5764). (B) Simplified geological map of the Isle of Wight. (C) Enlarged area showing the site of the excavation of MIWG 6643 in the Black Band (arrowed) (50.63354 N, 1.40654 W). Abbreviation: SS, sandstone. Note that the dashed line in (A) dividing the Wessex Formation into exposed and unexposed, applies only to the Isle of Wight exposures. Lockwood et al. (2025).

During the excavation of the specimen from which Istiorachis macarthurae is described,  MIWG 6643 was discovered and excavated by the late Nick Chase, a prolific Isle of Wight Dinosaur-hunter, who died of cancer in 2019. Unfortunately, during this excavation, the site was poached, and an unknown amount of material removed. The remaining material comprises one cervical vertebra, eight dorsal vertebrae, three dorsal rib heads, a partial sacrum, seven caudal vertebrae, both pubes and both ischia. Despite these loses, the remaining material is in good condition, with little distortion and good surface preservation.

Istiorachis macarthurae, holotype (MIWG 6643). Skeletal reconstruction. Scale bar represents 500 mm. Lockwood et al. (2025).

The most notable feature of Istiorachis macarthurae is the extremely long neural spines on its dorsal vertebrae. This is a trait which arose independently multiple times in Cretaceous Iguanodontians, although its purpose is unclear. 

Istiorachis macarthurae, holotype (MIWG 6643). 12th dorsal vertebra from early posterior series. (A)–(D), 12th dorsal vertebra in: (A) anterior; (B) left lateral; (C) posterior; (D) right lateral view. (E) reconstruction to show two consecutive vertebrae in lateral view. Abbreviations: cle, cleft; para, parapophysis; ri, ridge. Scale bar represents 50 mm. Lockwood et al. (2025).

A variety of modern Lizards have distinctive sails on their backs formed by elongation of the neural spines, but this is a feature associated with sexual selection and found only in the males. Such a role cannot be ruled out in Iguanodontians, but no evidence of sexual dimorphism has been found within the group (i.e., as far as we are aware, the males and females looked essentially the same). 

A Green Basilisk Lizard, Basiliscus plumifrons, in Alajuela Province, Costa Rica. This species has a distinctive crest, formed by elongation of the neural spines, but this trait is only seen in the males. Connor Long/Wikimedia Commons.

Large sails formed by elongated neural spines are also known from several groups of Carboniferous and Permian Tetrapods, including Sphenacodontids such as Dimetrodon limbatus and Echinerpeton intermedium, and Edaphosaurids, such as Edaphosaurus pogonias. In these Late Palaeozoic Tetrapods large sails appear to have been linked to temperature regulation. This cannot be ruled out in Iguanodontians, but where this the case crests would be expected to be a fixed trait (i.e. arising once then found in all subsequent members of the group), instead they seem to have appeared several times within different Iguanodontian lineages, with some groups having apparently gained and then lost crests.

Reconstructed skeleton of Dimetrodon incisivum from the Permian of Texas, in the collection of the Staatliches Museum für Naturkunde Karlsruhe in Germany. Such crests are thought to have been used for thermoregulation, and are a fixed trait within the Family Sphenacodontidae. Wikimedia Commons.

American Bison, Bison bison, have elongated neural spines on the forward part of their dorsal spine, which help to support the musculature needed to carry and move their large heads. Again, it is possible that the crests of Iguanodontians served a similar purpose, supporting extra musculature, but the distribution of elongated neural spines appears unrelated to size in the group, and it is unclear why this would have been present in some species, and absent in other, similar sized, species.

The skeleton of an American Bison, Bison bison, showing a crest made from elongated neural spines on the forward part of the dorsal spine. Museu de Anatomia Veterinária de Universidade de São Paulo/Wikimedia Commons.

Iguanodontians were secondarily quadrupedal grazing herbivores (that is to say, they descended from bipedal ancestors, but adopted a quadruped posture to facilitate grazing close to the ground). This required their spine be held in a horizontal position, and as they evolved to large sizes, to be able to bear large weights. To facilitate this, Iguanodontians evolved a system of ossified tendons, providing additional support for the spine, but also making it ridged and inflexible. 

Lockwood et al. speculate that elongated neural spines in Iguanodontians would have increased the efficiency of these ossified tendons, allowing for a reduction in muscle mass, which in turn would have enabled functions such as bending or running to be more efficient and less energetic. However, they are unable to explain why this would have been advantageous to some Iguanodontians but not others, and therefore the patchy distribution of the trait within the group.

Artist's impression of Istiorachis macarthurae in life. James Brown in Lockwood et al. (2025).

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Chyliza colenutti: A new species of Chylizine Rust Fly from the Eocene of the Isle of Wight.

Rust Flies, Psilidae, are small-to-medium sized Dipteran ('True') Flies with elongate bodies and rounded heads, found largely in temperate regions of the Northern Hemisphere. Their larvae are parasitic on Plants, and some species, such as the Carrot Fly, Chamaepsila rosae, are considered to be significant agricultural pests. The Family Psilidae is divided into three subfamilies, the Chylizinae and Psilinae, which are considered to be sister groups, and the Belobackenbardiinae, which forms a sister to the other two groups combined. The oldest known fossil Rust Fly is Electrochyliza succini from Baltic Amber, which is probably Late Eocene in age. Electrochyliza succini is not placed within any extant subfamily, being considered to be a sister taxon to Chylizinae and Psilinae closer than Belobackenbardiinae, which suggests it appeared after the ancestor of these groups split from the Belobackenbardiinae, but before they had themselves diverged. 

In a paper published in the journal Insect Systematics and Diversity on 13 November 2024, Andrew Ross of the Department of Natural Sciences at National Museums Scotland, Jiale Zhou of the Key Laboratory of Zoological Systematics and Evolution at the Institute of Zoology of the Chinese Academy of Sciences and the Department of Entomology at the China Agricultural University, Christel Hoffeins of Hamburg in Germany, and Bill Crighton, also of the Department of Natural Sciences at National Museums Scotland, describe a new species of Chylizine Rust Fly from the Late Eocene Insect Limestone Bed of the Bembridge Marls of the Isle of Wight, England.

The Insect Limestone is a single bed of fine-grained micrite found within the Bembridge Marls member of the Bouldnor Formation on the Isle of Wight. This bed is noted for the production of exquisitely preserved Insects, which often show three-dimensional preservation, for which reason it is sometimes known as 'opaque amber'. This bed has been precisely dated to 34.3 million years before the present.

The new species is described upon the basis of a single specimen collected by George William Colenutt, a prominant Isle of Wight solicitor and amateur geologist, and donated to the Oxford University Museum of Natural History in 1931. The species is placed in the genus Chyliza, the sole genus in the subfamily Chylizinae, on the basis of comparison of its wing venation to that of living members of the genus, and named Chyliza colenutti in honour of the collector.

Chyliza colenutti, Holotype; (A) part, OUMNH M.177; (B) counterpart, OUMNH M.175; Insect Limestone, Bembridge Marls, north-west Isle of Wight, UK. Colenutt Collection. Scale bar is 5 mm. Ross et al. (2024).

The specimen is preserved in a split block as part and counterpart, and has a preserved body length of 3.9 mm and a maximum abdomen width of 1 mm. The forewing is 3.6 mm in length and 1.4 mm wide. All of the wings appear coloured towards their tips.

Prior to the description of Chyliza colenutti, the oldest described Chylizine Rust Fly was a Middle Miocene specimen identified as Chyliza sp. from the Middle Miocene Upper Freshwater Molasse of southwestern Germany, which is thought to be between 15 and 12 million years old. 

The dating of Baltic Amber can be problematic, as it ranges from Middle Eocene to Middle Oligocene in age (i.e. is between 48 and 27  million years old), and tends to reach collections via amber dealers, often trading hands several times before coming to the attention of a scientist, with any data on the location and age of the specimens often being lost. However, the majority of Baltic Amber comes from the Upper Blue Earth Member of the Prussian Formation, which has been dated to between 36.5 and 33.5 million years old. 

Electrochyliza succini in Baltic amber. Hoffeins Collection CCHH 1829-10. Scale bar is 1 mm. Ross et al. (2024).

This gives a gap of around 20 million years between Electrochyliza succini and Chyliza sp., which led many palaeoentomologists to conclude that there was a long gap between the divergence of the Belobackenbardiinae from the common ancestor of the Chylizinae and Psilinae, and the splitting of these two groups, particularly as no specimens assigned to either of these groups have been found in Insect-rich deposits such as the Dominican and Mexican ambers. However, if Ross et al.'s interpretation of Chyliza colenutti as a Chylizine is correct, then the group was present 34.2 million years ago, making it unlikely that it is more than two million years younger than Electrochyliza succini.

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Homes evacuated following major landslide on the Isle of Wight.

Residents of 20 homes on the south coast of the Isle of Wight, England, have been evacuated following a massive landslip on Sunday 10 December 2023. The event happened at about 9.30 pm local time, on cliffs in the village of Bonchurch on the eastern fringe of the town of Ventnor, which fractured causing the cliff face to retreat by about 20 m. Inspections by the Isle of Wight Council suggest that fractures in the rock extend some way beyond the area which has collapsed already, making it highly likely that further collapses will occur.

A landslip in the village of Bonchurch on the Isle of Wight. Island Echo.

The landslip is thought to be linked to the exceptionally high levels of rain on the island this year, with 110 mm of rain falling in August, 64 mm in September, 250 mm in October and 200 mm in November. The cliffs at Bonchurch are made of chalk, a soft form of limestone through which water permeates slowly, and which will eventually become waterlogged and prone to collapse after extended periods of rain.

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Vectipelta barretti: A new species of Ankylosaurian Dinosaur from the Early Cretaceous of the Isle of Wight.

The Ankylosaurs are Ornithischian Dinosaurs noted for their broad body, short limbs and extensive covering of dermal armour on the head, body and tail. They are a diverse group, found on all continents, but reaching their greatest diversity on the continents of the former Laurasian landmass, i.e. North America, Europe, and Asia. They split from their sister group, the Stegosaurs, in the Early or early Middle Jurassic, but appear to have remained a minor component of most ecosystems until the Early Cretaceous, when they underwent a significant radiation, remaining a significant member of the herbevore community until their demise in the End Cretaceous extinction. 

A number of Ankylosaurs have been described from the UK, from the Middle Jurassic onwards, although the group reach their maximum abundance in the UK in the Early Cretaceous Wealden Group of southern England. For a long time, all Ankylosaurs from the Wealden Group were referred to two species, Polacanthus foxii and Hylaeosaurus armatus, but this is now thought likely to hide considerable diversity, as the Wealden Group is thought to cover at least 8 million years of time, including all of the Barremian Stage and part of the Aptian.

Traditionally, all Ankylosaur material from the Isle of Wight was referred to Polacanthus foxii, but a recent study of Ankylosaur diversity within the Wealden Group, led by Thomas Raven of the Fossil Reptiles, Amphibians and Birds Section at the Natural History Museum, has suggested that this name should be restricted to the holotype specimen, NHMUKPV R175, and other specimens should be considered taxonomically uncertain until re-examined. One notable specimen examined in Raven et al.'s study was IWCMS 1996.153, known as the Spearpoint Ankylosaur, which was shown to be particularly different to the Polacanthus foxii holotype, and not likely to be closely related.

In a paper published in the Journal of Systematic Palaeontology on 15 June 2023, Stuart Pond, also of the Fossil Reptiles, Amphibians and Birds Section at the Natural History Museum, Sarah-Jane Strachan of the Department of Earth Sciences at University College London, Thomas Raven (again), Martin Simpson of Lansdowne on the Isle of Wight, Kirsty Morgan of Fayetteville in Arkansas, and Susannah Maidment, again of the Fossil Reptiles, Amphibians and Birds Section at the Natural History Museum, formally describe the Spearpoint Ankylosaur as the holotype of a new species.

The Wessex Group consists of a series of terrestrial, lacustrine, flu-vial and lagoonal deposits which outcrop in the Wessex Sub-basin of the Isle of Wight and the Weald Sub-basin of south-east England. On the Isle of Wight the group comprises two formations, the Wessex Formation, considered Barremian in age, and the Vectis Formation, thought to be late Barremian to early Aptian. The Wessex Formation is a sequence about 180 m thick, consisting of variegated mudstones and interbedded sandstones deposited as river channel, floodplain and point bar deposits by a high-sinuosity river system flowing west to east. The overlying Vectis Formation is thought to have been laid down in a shallow lagoon. The largest exposures of both formations are on the southwestern coast of the Isle of Wight, with smaller exposures at Yaverland on the south-east coast.

The Wessex Formation is thought to have been laid down in a Mediterranean climate, with distinctive dry and wet seasons, the latter associated with periodic flood events in which debris flows including large trees and Dinosaur remains were swept down from the (now lost) highlands from which the river descended, and were deposited on the flood plain. This formation is rich in fossils, producing numerous Plant (particularly Gymnosperms), Invertebrates, trace fossils, and a diverse Vertebrate assemblage, including Bony Fish, Turtles, Crocodilians, Pterosaurs and Dinosaurs.

The Spearpoint Ankylosaur was discovered within the Compton Chine to Steephill Cove Site of Special  Scientific Interest, about 50 m to the west of Chilton Chine. Chines on the Isle of Wight, are gullies which cut into the overlying chalk grassland by seasonal streams, and emerging from the cliffs as waterfalls. These features never erode down to beach level, as the cliffs are eroded backwards by the action of the sea faster than the chines are eroded downwards by the streams, and form a unique environment with their own distinctive flora and fauna, including many rare Plants and Insects.

In November 1993 fossil hunter Gavin Leng found several Ankylosaur vertebrae on beach, which he later donated to the Dinosaur Isle Museum. The following spring another fossil hunter Lin Spearpoint, discovered the remainder of the skeleton in the cliffs above, on land belonging to dairy farmer Richard Fisk. Fisk gave permission for Lin Spearpoint, Dick Spearpoint, and Martin Simpson, to excavate the skeleton, which was then prepared by Lin Spearpoint, housed at the University of Southampton, where it was the subject of several MSci, MRes and PhD projects, some of which were carried out by Stuart Pond, Sarah-Jane Strachan, and Kirsty Morgan, temporarily displayed at the SeaCity  Museum,  Southampton, and eventually acquired by the Dinosaur Isle Museum. 

Pond et al. formally describe the Spearpoint Ankylosaur as the holotype of a new species, Vectipelta barretti, where 'Vectipelta' means 'Vectis-shield' (Vectis was the name used by the Romans for the Isle of Wight), and 'barretti' honours Paul Barrett of the Natural History Museum, in recognition of his major and ongoing contributions to Dinosaurian Vertebrate palaeontology, and his importance to Stuart Pond, Thomas Raven and Susannah Maidment as a mentor, supervisor, colleague and friend.

Geological setting and stratigraphy. (A) Map of Isle of Wight with the extent of Wessex Sub-basin marked in orange, and the site of the Vectipelta barretti (IWCMS 1996.153 and IWCMS 2021.75) excavation indicated by the black arrow. (B) Schematic stratigraphical log of the outcrop between Sudmore Point and Ship Ledge showing the approximate stratigraphical location of Vectipelta barretti (IWCMS 1996.153 and IWCMS 2021.75). Pond et al. (2023).

The new species is described from two specimens, both believed to have come from the same individual and therefore treated as one. WCMS1996.153 comprises portions of four cervical vertebrae and six  free dorsal vertebrae discovered on the foreshore by Gavin Leng in 1993, while IWCMS 2021.75 comprises five fused dorsal vertebrae, forming the sacral rod, fragments of several dorsal ribs, a fused sacrum made up of four and a half fused vertebrae, thirteen caudal vertebrae, and fragments of four more, the proximal part of the left scapula, the proximal and distal ends of the left humerus, a possible ulna fragment, multiple pieces of the iliosacral block, including parts both the left and right ilia, both pubes, fused to the anteromedial margins of the acetabula, a more-or-less complete left ischium, some possible fibula fragments, and second metatarsal, the sacral shield, a large number of osteoderms, and three recurved spines. Specimen IWCMS 2021.75 was found lying on its back, with its (missing) head pointing towards the cliff face, leading to the assumption that the cervical and upper dorsal vertebrae of WCMS1996.153 came from the same individual. Pond et al, note that several years prior to the discovery of WCMS1996.153, a beach-rolled Ankylosaur braincase was found at the same location by fossil hunter David Cooper, and acquired by the University of Cambridge's Sedgwick Museum, and a partial femur and posterior part of an ilium were found nearby by David Richards in the 1990s and donated to the Natural History Museum. These specimens may also relate to the Spearpoint Ankylosaur, but all are heavily eroded, making it impossible to assess them with any confidence, so they were excluded from the study.

Holotype material of Vectipelta barretti, IWCMS 1996.153 and IWCMS 2021.75 in (A) dorsal view; (B) left lateral view; (C) dorsal view of the osteoderms only; (D) complete skeletal reconstruction, in left lateral view. Scale baris 1m. Pond et al. (2023).

The recurved spines of the Spearpoint Ankylosaur are notable, as NHMUKPV R175, the holotype of Polacanthus foxii, lacks any such structure, supporting the idea that the two are quite different Animals. Some spines assigned to Polacanthus sp. have been described from Early Cretaceous of Soria, Spain, but these are also unlikely to derive from that genus. Recurved spines are known in a wide range of Ankylosaurs, including the other Wealden Group species, Hylaeosaurus armatus, but the form of the Spearpoint Ankylosaur's spines is different to any of these, supporting the idea that it should be described as a new species.

Vectipelta barretti, IWCMS 2021.75. Examples of recurved spines. Orientation presumed: (A)–(C) proximal; (D)–(F) distal; (G)–(I) left lateral; (J)–(L) right lateral; (M)–(O) anterior; (P)–(R) posterior. Scale bar is 10 cm. Pond et al. (2023).

Understanding the diversity of Early Cretaceous Ankylosaurs is not just important because we are interested in Dinosaurs; it has implications for our understanding of Mesozoic ecosystems and geology as a whole. The Jurassic is believed to have ended with a mass extinction event, although the nature of this is poorly understood. Terrestrial deposits with good fossil preservation are rare from the Early Cretaceous, leading to the apparent emergence of a quite new ecosystem in the Middle Cretaceous. However, the clustering of multiple specimens from diverse groups under a few poorly constrained species names in Early Cretaceous deposits, as has happened with Wealden Ankylosaurs (and, it has also been suggested, Iguanodontids), could be hiding a more gradual faunal turnover during this interval.

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Cycas revoluta: Cycads 'flowering' on the Isle of White.

The Ventnor Botanic Garden on the Isle of Wight, southern England, has reported that a species of Cycad, the Japanese Sago Palm, Cycas revoluta, (not actually a Palm) has begun 'flowering' on the island, for the first time in Human history. The 'flower' of a Cycad is not a true flower, it is a modified cone, similar to that of a Pine or other Gymnosperm, but is modified for Insect pollination (typically by Beetles), making it large and conspicuous. Cycads are dioeceous, which is to say each plant is either male or female, and typically produce only one large 'flower' each breeding season. They were a dominant Plant group during the Mesozoic, but today are restricted to warmer climates, with the most northerly populations known in Florida and southern Japan. The youngest fossil Cycads from Europe come from the Oligocene Frauenweiler clay pits of Baden-Württemberg in Germany, deposits dated to between 33.9 and 28.4 million years old. They are widely grown in Europe as introduced ornamentals today, but this appears to be the first instance of them flowering outdoors in Northern Europe recorded. The event has been linked to the exceptional heatwave being experienced in Europe at the moment, with many areas having recorded their hottest ever temperatures this summer. Both male and female plants have been flowering at the Ventnor Gardens, and as the area is not home to pollinating Cycad Beetles, and the plants are too far apart to cross-pollinate by other means, staff at the gardens intend to pollinate them artificially.

A male Cycad flower on the Isle of Wight this year. Ventnor Botanic Garden.

Cycad’s are of particular interest to botanists and horticulturalists due to their unique evolutionary heritage; they are Gymnosperms (non-flowering Seed Plants), members of the group that includes Conifers and Ginkos, but among the closest non-flowering relatives of the Angiosperms (Flowering Plants). They large attractive plants, superficially resembling Palms, but producing large and often brightly coloured strobili, structures intermediate between cones and flowers; these are often pollinated by Beetles or Thrips.  Cycads are thought to have originated during the Permian, and became dominant Plants in many ecosystems during the Jurassic and Cretaceous, but suffered heavily during the End Cretaceous Extinction, and there are about 330 species surviving today, predominantly in the Southern Hemisphere, most of which diversity is thought to have arisen from a post-Cretaceous radiation.

 The approximate distribution of Cycads today. Wikimedia Commons.

There are over 330 known living species of Cycads, the majority of which are listed on the International Union for the Conservation of Nature’s Red List of Threatened Species, with more than 75% of known species currently thought to be threatened with extinction. Cycads are threatened by habitat loss and invasive species (particularly Insects), but are considered to be most at risk due to over-collecting for horticulture. The distinctive evolutionary history of the plants, combined with their attractive appearance and drought tolerance, makes them highly sought after by plant collectors, however they are slow growing and difficult to raise from seed, resulting in a high market value for mature plants, which leads to many being taken from the wild. Four species of Cycad are considered to be extinct in the wild, and it is not thought it will be possible to reintroduce them to their former environments, as Cycads are usually co-dependent on single species of pollinators, typically Weevils, with neither species able to survive in the absence of the other.

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Neovenator salerii: The neuroanatomy of the rostrum of an Early Cretaceous Allosauroid Dinosaur.

Neovenator salerii is an Early Cretaceous Allosauroid Theropod Dinosaur, known from a single partial skeleton from the Wessex Formation of the Isle of Wight. The skull of this skeleton is exceptionally well preserved, being deep and laterally (sideways) flattened, with blade-like teeth. This has been interpreted as indicative of a terrestrial apex predator, with a hunting technique that is likely to have involved targeting soft tissues, then defleshing with the sharp teeth, but avoiding biting down on bone or other hard tissue, which would produce wear marks on the teeth that are not seen (this is seen in some modern predators, such as Cheetahs).

In a paper published in the journal Scientific Reports on 16 June 2017, Chris Tijani Barker and Darren Naish of the National Oceanography Centre at the University of Southampton, Elis Newham and Orestis Katsamenis of the Faculty of Engineering and the Environment, also at the University of Southampton, and Gareth Dyke of the Department of Evolutionary Zoology and Human Biology at the University of Debrecen, and the Center for Interdisciplinary Biosciences at Pavol Jozef Safarik University, describe the results of a study of the cranial morphology of Neovenator salerii using microfocus μCT to investigate the distribution of its rostral foramina (the openings of channels within the bones of the snout through which nerves and blood vessels pass)and any internal preservation.

Barker et al. found that Neovenator salerii has an extensive network of channels within its maxilla and premaxilla running laterally (to the outside of) the dental alveoli, and connected to opening on the outer side of the bone. This is interpreted as part of the neurovascular system, occupying at least 7.3% and 6.7% of the internal volume of the premaxilla and maxilla, respectively. 

Complex anastomosing neurovasculature surrounding infilled dental alveoli of the premaxilla of Neovenator. (A) Volume rendering of left premaxilla in lateral view with foramina highlighted (blue). (B) Volume rendering of infilled voids. Barker et al. (2017).

Similar structures have previously been found in Pliosaurids (Mesozoic Marine Reptiles) and the Spinosaurids Spinosaurus and Baryonyx (Theropod Dinosaurs interpreted as having been partially aquatic). For this reason, the structures have been interpreted as sensory in nature, used to detect potential prey moving in the water. However, Neovenator appears to have no adaptations to an aquatic lifestyle, suggesting that the channels must have a different purpose.

Similar channels are found in a number of living animals notably some species of Birds, particularly those that engage in probe feeding, such as Kiwis (Apterygidae), Waders (Scolopacidae), and Ibises (Threskiornithidae), as well as in Ducks and Geese (Anseriformes), which use their beaks in a variety of ways for the detection, recognition, and transport of food, and Parrots (Psittaciformes), which are capable of extremely fine manipulation of objects with their beaks, including tool use. Beaks are known in a range of non-Avian Dinosaurs, including many Ornithischians and some Theropod groups, such as Ornithomimosaurs, Therizinosaurs, Oviraptorosaurs and some Ceratosaurs, but there is no evidence of any such structure in any Allosauroid, and nothing known about the biology of Neovenator suggests that it might have had a beak. 

Complex anastomosing neurovasculature surrounding infilled dental alveoli of the maxilla of Neovenator. (A) Volume rendering of left maxilla in lateral view with foramina highlighted (blue). (B) Volume rendering of infilled voids. Abbrevations: aor: antorbital ridge; asr: ascending ramus; ifs: interfenestral strut; laof: lateral antorbital fossa; maf: maxillary alveolar foramina; mcf: maxillary circumfenestra foramina; mfe: maxillary fenestra; mmf: medial maxillary foramina; pab: preantorbital body; pne: pneumatic excavation. Barker et al. (2017).

Channels of this type are also known in modern animals which lack beaks, notably Crocodylians, where it is associated with the detection potential prey moving in the water (as has been speculated for Pliosaurids and Spinosaurids), as well as temperature regulation. The very narrow snout seen in Neovanator makes a role in temperature regulation unlikely, as the snout would have shed excess heat (the only real issue for an animal this size) very efficiently without it. This makes it likely that the channels seen in the maxillary bones of Spinosaurus did indeed carry nerves rather than blood vessels. Barker et al. therefore speculate that the species, and other large Theropods such as Tyranosaurids, was probably capable of highly controlled snout movements, both when subduing prey and manipulating food, and that this would have been useful to an animal which needed to avoid brining very sharp, but not particularly strong, teeth into contact with the bone or other hard tissues of its prey.

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