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BEXHM: 2008.14.1 shown in approximate life position within a generalised maniraptoran silhouette. The exact identity of this maniraptoran remains unknown: it is depicted as a generic member of the group, closely related to oviraptorosaurs and paravians. By duplicating and manipulating images of BEXHM: 2008.14.1, a schematic cervical column was generated and scaled to approximate size within the silhouette. This suggests a total skeletal length for the animal of c. 45 cm, though other body shapes suggest the possibility of smaller size (see text for discussion).
Source publication
a b s t r a c t In contrast to the Barremian Wessex Formation on the Isle of Wight, the remains of small theropods are rare in the BerriasianeValanginian Hastings Group of the English mainland. Both units are part of the dinosaur-rich Wealden Supergroup (BerriasianeAptian) of southern Britain. Here we report the cervical vertebra of a small dinosau...
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Context 1
... located parapophyses of the specimen indicate that it is most likely a posterior cervical. The X-like shape of the neural arch evident in dorsal view (Fig. 4E) recalls that seen in some oviraptorosaurian maniraptorans (Makovicky and Sues, 1998; He et al., 2008), and other characters present in the specimen are consistent with a maniraptoran identity, such as the amphicoelous centrum, large hypapophysis, and infraprezygapophyseal fossa. The squarish centrum and tall neural arch makes the specimen look rather different from the cervicals of therizinosaurs and caenagnathid oviraptorosaurs, which have elongate, shallow centra and long, low neural arches. The subparallel anterior and posterior articular and dorsal and ventral surfaces of the centrum are also rather different from the offset anterior and posterior surfaces and posteroventrally sloping ventral centrum surfaces present in the cervicals of dromaeosaurids and troodontids. Riff et al. (2004) suggested that a proportionally large neural canal (taller than the anterior articular surface of the centrum) can evidence avialian af fi nity for maniraptoran vertebrae. This is because Chiappe (1996) used the same character to help differen- tiate birds from non-avialian theropods: in the latter, the neural canal/articular surface ratio is less than 0.4, whereas it is higher in birds. In the Ashdown specimen, the neural canal is proportionally large, with the neural canal/articular surface ratio being approximately 0.7 anteriorly. While this feature is consistent with an avialian identity, it is not conclusive: we suspect that it is size- related and that small non-avialian theropods also have proportionally tall neural canals. Nevertheless, an avialian identity for the specimen cannot be excluded. Hypapophyses are present on the cervicals and anterior dorsals of species in several theropod clades, including megalosaurids, allosauroids, alvarezsaurids, oviraptorosaurs, dromaeosaurids and troodontids. However, the large, anteriorly positioned hypapophysis of the Ashdown specimen most resembles those seen in maniraptorans; notably, the hypapophyses of some troodontids are highly similar in shape and position to that of the Ashdown cervical (Makovicky and Norell, 2004). The Bexhill vertebra cannot be referred to any Wealden theropod for which cervical vertebrae are known, but this is not surprising given that the taxa concerned are all geologically younger. The neural arch and centrum are longer and lower in Wessex Formation coelurosaur cervicals, such as the holotypes of Thecocoelurus daviesi and Calamosaurus foxi , and the position of these taxa within Theropoda remains uncertain. Thecocoelurus daviesi , conventionally interpreted as belonging to a small, unspeci fi ed theropod, was argued by Naish et al. (2001) and Naish and Martill (2002) to represent a caenagnathid oviraptorosaur, as NHMUK 181 (the Thecocoelurus daviesi holotype) shares an hourglass shaped ventral surface to the centrum, ventral sulcus, and lateroventral keels on the centrum with caenagnathids (Sues, 1997). However, these features have since proved to be present elsewhere within Theropoda: Agnolin and Martinelli (2007) showed that an alleged oviraptorosaur cervical from the El Brete Formation of Argentina (identi fi ed as oviraptorosaurian on the basis of the characters listed above) is actually from an abelisauroid. The two Calamosaurus foxi cervicals are strongly opisthocoelous and hence clearly distinct from the Bexhill specimen. The strong super fi cial similarity of the Calamosaurus foxi specimens to the cervicals of the basal tyrannosauroid Dilong paradoxus , led Naish and Martill (2007) to propose a basal tyrannosauroid identity for this taxon, though this is speculative in view of the poor quality of the material. Finally, the two poorly preserved cervical neural arches of Eotyrannus lengi are from a much larger animal (neural arch length 1⁄4 50 mm and 72 mm for the axis and a post-axial cervical) and possess long, low, subrectangular neural spines. Furthermore, while the cervical centra of Eotyrannus lengi are amphicoelous like the Bexhill specimen, they possess lateral foramina. In conclusion, the specimen is tentatively referred to Maniraptora, but probably does not belong to a deinonychosaur. An identi fi cation of Maniraptora indet. seems most prudent, but we note some similarities with members of Avialae and Oviraptorosauria. The specimen is not only noteworthy for being a maniraptoran, but also for being remarkably small, despite its adult status (Table 1). We used two techniques in an attempt to assess the total size of the animal to which it belongs, though we are very much aware that this is a highly speculative endeavour given the material. In one (wholly intuitive) technique, approximately scaled images of BEXHM: 2008.14.1 were combined to form a schematic neck skeleton; this was then placed in approximate position within a silhouette depicting a generic maniraptoran (Fig. 5). The total length of the silhouette was then calculated: it is c. 450 mm. A second technique involves estimating the length of the cervical column, and then using proportional data from better known maniraptorans to estimate total skeletal length. Mesozoic maniraptorans (e.g., basal oviraptorosaurs, dromaeosaurids and Archaeopteryx ) typically possess 9 e 12 cervical vertebrae. The Bexhill maniraptoran was arbitrarily imagined as having 10 cervical vertebrae. If all the vertebrae in its neck were identical in length, the neck would be 71 mm long (the centrum length of the Bexhill vertebra is 7.1 mm). However, vertebrae are not the same length throughout the cervical series: in Deinonychus antirrhopus , for example, the centra of anterior cervical vertebrae are 19% longer than those near the cervicodorsal junction (Ostrom, 1969). On the assumption that this difference also existed in the Bexhill maniraptoran, anterior cervical vertebrae might have been 8.5 mm long (19% longer than 7.1 mm). A neck combining 10 vertebrae with centrum lengths of between 8.5 mm and 7.1 mm (and assuming a gradation of sizes in between) produces a total neck length of c. 79.6 mm (note that this is similar to the neck length depicted in Fig. 5). Articulated maniraptoran specimens reveal total neck length to be anywhere from c. 24% ( Caudipteryx zoui ), c. 34% ( Anchiornis huxleyi ) to c. 47% ( Archaeopteryx lithographica ) of total body length (calculated from scaled skeletal reconstructions in Paul (2010)). In early short-tailed birds (such as Confuciusornis sanctus ), neck length is c. 20% of total length (tail feathers are not included in total length in any of these measures). This variability, combined with our uncertainty about the precise af fi nities of the Bexhill maniraptoran vertebra, renders it impossible to accurately estimate total length. Neverthless, if proportioned like Caudipteryx , the Bexhill maniraptoran might have a total length of c. 330 mm. If proportioned like Archaeopteryx , total length could be as low as c. 169 mm while a total skeletal length of c. 398 mm is conceivable if the animal is a short-tailed bird. While we emphasise that this exercise includes diverse possi- bilities and unknown variables (concerning number and centrum length of cervical vertebrae, total length of cervical series, and length of neck compared to animal ’ s total length), it nevertheless seems likely that the Bexhill maniraptoran was between 16 and 40 cm in total skeletal length (Fig. 5). Given the specimen ’ s adult status, this indicates that the taxon to which it belongs was one of the smallest Mesozoic dinosaurs yet reported. It may have been similar in size, or even smaller, than the most diminutive non- avialian dinosaur currently known: Anchiornis huxleyi ; a species variously estimated to have a total length of 34 cm (Xu et al., 2008) or 40 cm Paul (2010). We thank David Brockhurst for bringing this specimen to our attention and David Brockhurst and Peter and Joyce Austen for providing measurements of the section as currently exposed. Steve Chapman of Ibstock Brick Limited is thanked for providing borehole data and access to the pit. We are also grateful for the assistance of staff at Bexhill Museum and in particular the curator Julian Porter. Roger Benson and Andrea Cau are thanked for discussion and Malcolm Hart and an anonymous reviewer provided comments that improved the manuscript. Bob Loveridge, University of Portsmouth, is thanked for assistance with ...
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... coelurosaur cervicals, such as the holotypes of Thecocoelurus daviesi and Calamosaurus foxi , and the position of these taxa within Theropoda remains uncertain. Thecocoelurus daviesi , conventionally interpreted as belonging to a small, unspeci fi ed theropod, was argued by Naish et al. (2001) and Naish and Martill (2002) to represent a caenagnathid oviraptorosaur, as NHMUK 181 (the Thecocoelurus daviesi holotype) shares an hourglass shaped ventral surface to the centrum, ventral sulcus, and lateroventral keels on the centrum with caenagnathids (Sues, 1997). However, these features have since proved to be present elsewhere within Theropoda: Agnolin and Martinelli (2007) showed that an alleged oviraptorosaur cervical from the El Brete Formation of Argentina (identi fi ed as oviraptorosaurian on the basis of the characters listed above) is actually from an abelisauroid. The two Calamosaurus foxi cervicals are strongly opisthocoelous and hence clearly distinct from the Bexhill specimen. The strong super fi cial similarity of the Calamosaurus foxi specimens to the cervicals of the basal tyrannosauroid Dilong paradoxus , led Naish and Martill (2007) to propose a basal tyrannosauroid identity for this taxon, though this is speculative in view of the poor quality of the material. Finally, the two poorly preserved cervical neural arches of Eotyrannus lengi are from a much larger animal (neural arch length 1⁄4 50 mm and 72 mm for the axis and a post-axial cervical) and possess long, low, subrectangular neural spines. Furthermore, while the cervical centra of Eotyrannus lengi are amphicoelous like the Bexhill specimen, they possess lateral foramina. In conclusion, the specimen is tentatively referred to Maniraptora, but probably does not belong to a deinonychosaur. An identi fi cation of Maniraptora indet. seems most prudent, but we note some similarities with members of Avialae and Oviraptorosauria. The specimen is not only noteworthy for being a maniraptoran, but also for being remarkably small, despite its adult status (Table 1). We used two techniques in an attempt to assess the total size of the animal to which it belongs, though we are very much aware that this is a highly speculative endeavour given the material. In one (wholly intuitive) technique, approximately scaled images of BEXHM: 2008.14.1 were combined to form a schematic neck skeleton; this was then placed in approximate position within a silhouette depicting a generic maniraptoran (Fig. 5). The total length of the silhouette was then calculated: it is c. 450 mm. A second technique involves estimating the length of the cervical column, and then using proportional data from better known maniraptorans to estimate total skeletal length. Mesozoic maniraptorans (e.g., basal oviraptorosaurs, dromaeosaurids and Archaeopteryx ) typically possess 9 e 12 cervical vertebrae. The Bexhill maniraptoran was arbitrarily imagined as having 10 cervical vertebrae. If all the vertebrae in its neck were identical in length, the neck would be 71 mm long (the centrum length of the Bexhill vertebra is 7.1 mm). However, vertebrae are not the same length throughout the cervical series: in Deinonychus antirrhopus , for example, the centra of anterior cervical vertebrae are 19% longer than those near the cervicodorsal junction (Ostrom, 1969). On the assumption that this difference also existed in the Bexhill maniraptoran, anterior cervical vertebrae might have been 8.5 mm long (19% longer than 7.1 mm). A neck combining 10 vertebrae with centrum lengths of between 8.5 mm and 7.1 mm (and assuming a gradation of sizes in between) produces a total neck length of c. 79.6 mm (note that this is similar to the neck length depicted in Fig. 5). Articulated maniraptoran specimens reveal total neck length to be anywhere from c. 24% ( Caudipteryx zoui ), c. 34% ( Anchiornis huxleyi ) to c. 47% ( Archaeopteryx lithographica ) of total body length (calculated from scaled skeletal reconstructions in Paul (2010)). In early short-tailed birds (such as Confuciusornis sanctus ), neck length is c. 20% of total length (tail feathers are not included in total length in any of these measures). This variability, combined with our uncertainty about the precise af fi nities of the Bexhill maniraptoran vertebra, renders it impossible to accurately estimate total length. Neverthless, if proportioned like Caudipteryx , the Bexhill maniraptoran might have a total length of c. 330 mm. If proportioned like Archaeopteryx , total length could be as low as c. 169 mm while a total skeletal length of c. 398 mm is conceivable if the animal is a short-tailed bird. While we emphasise that this exercise includes diverse possi- bilities and unknown variables (concerning number and centrum length of cervical vertebrae, total length of cervical series, and length of neck compared to animal ’ s total length), it nevertheless seems likely that the Bexhill maniraptoran was between 16 and 40 cm in total skeletal length (Fig. 5). Given the specimen ’ s adult status, this indicates that the taxon to which it belongs was one of the smallest Mesozoic dinosaurs yet reported. It may have been similar in size, or even smaller, than the most diminutive non- avialian dinosaur currently known: Anchiornis huxleyi ; a species variously estimated to have a total length of 34 cm (Xu et al., 2008) or 40 cm Paul (2010). We thank David Brockhurst for bringing this specimen to our attention and David Brockhurst and Peter and Joyce Austen for providing measurements of the section as currently exposed. Steve Chapman of Ibstock Brick Limited is thanked for providing borehole data and access to the pit. We are also grateful for the assistance of staff at Bexhill Museum and in particular the curator Julian Porter. Roger Benson and Andrea Cau are thanked for discussion and Malcolm Hart and an anonymous reviewer provided comments that improved the manuscript. Bob Loveridge, University of Portsmouth, is thanked for assistance with ...
Context 3
... theropods: in the latter, the neural canal/articular surface ratio is less than 0.4, whereas it is higher in birds. In the Ashdown specimen, the neural canal is proportionally large, with the neural canal/articular surface ratio being approximately 0.7 anteriorly. While this feature is consistent with an avialian identity, it is not conclusive: we suspect that it is size- related and that small non-avialian theropods also have proportionally tall neural canals. Nevertheless, an avialian identity for the specimen cannot be excluded. Hypapophyses are present on the cervicals and anterior dorsals of species in several theropod clades, including megalosaurids, allosauroids, alvarezsaurids, oviraptorosaurs, dromaeosaurids and troodontids. However, the large, anteriorly positioned hypapophysis of the Ashdown specimen most resembles those seen in maniraptorans; notably, the hypapophyses of some troodontids are highly similar in shape and position to that of the Ashdown cervical (Makovicky and Norell, 2004). The Bexhill vertebra cannot be referred to any Wealden theropod for which cervical vertebrae are known, but this is not surprising given that the taxa concerned are all geologically younger. The neural arch and centrum are longer and lower in Wessex Formation coelurosaur cervicals, such as the holotypes of Thecocoelurus daviesi and Calamosaurus foxi , and the position of these taxa within Theropoda remains uncertain. Thecocoelurus daviesi , conventionally interpreted as belonging to a small, unspeci fi ed theropod, was argued by Naish et al. (2001) and Naish and Martill (2002) to represent a caenagnathid oviraptorosaur, as NHMUK 181 (the Thecocoelurus daviesi holotype) shares an hourglass shaped ventral surface to the centrum, ventral sulcus, and lateroventral keels on the centrum with caenagnathids (Sues, 1997). However, these features have since proved to be present elsewhere within Theropoda: Agnolin and Martinelli (2007) showed that an alleged oviraptorosaur cervical from the El Brete Formation of Argentina (identi fi ed as oviraptorosaurian on the basis of the characters listed above) is actually from an abelisauroid. The two Calamosaurus foxi cervicals are strongly opisthocoelous and hence clearly distinct from the Bexhill specimen. The strong super fi cial similarity of the Calamosaurus foxi specimens to the cervicals of the basal tyrannosauroid Dilong paradoxus , led Naish and Martill (2007) to propose a basal tyrannosauroid identity for this taxon, though this is speculative in view of the poor quality of the material. Finally, the two poorly preserved cervical neural arches of Eotyrannus lengi are from a much larger animal (neural arch length 1⁄4 50 mm and 72 mm for the axis and a post-axial cervical) and possess long, low, subrectangular neural spines. Furthermore, while the cervical centra of Eotyrannus lengi are amphicoelous like the Bexhill specimen, they possess lateral foramina. In conclusion, the specimen is tentatively referred to Maniraptora, but probably does not belong to a deinonychosaur. An identi fi cation of Maniraptora indet. seems most prudent, but we note some similarities with members of Avialae and Oviraptorosauria. The specimen is not only noteworthy for being a maniraptoran, but also for being remarkably small, despite its adult status (Table 1). We used two techniques in an attempt to assess the total size of the animal to which it belongs, though we are very much aware that this is a highly speculative endeavour given the material. In one (wholly intuitive) technique, approximately scaled images of BEXHM: 2008.14.1 were combined to form a schematic neck skeleton; this was then placed in approximate position within a silhouette depicting a generic maniraptoran (Fig. 5). The total length of the silhouette was then calculated: it is c. 450 mm. A second technique involves estimating the length of the cervical column, and then using proportional data from better known maniraptorans to estimate total skeletal length. Mesozoic maniraptorans (e.g., basal oviraptorosaurs, dromaeosaurids and Archaeopteryx ) typically possess 9 e 12 cervical vertebrae. The Bexhill maniraptoran was arbitrarily imagined as having 10 cervical vertebrae. If all the vertebrae in its neck were identical in length, the neck would be 71 mm long (the centrum length of the Bexhill vertebra is 7.1 mm). However, vertebrae are not the same length throughout the cervical series: in Deinonychus antirrhopus , for example, the centra of anterior cervical vertebrae are 19% longer than those near the cervicodorsal junction (Ostrom, 1969). On the assumption that this difference also existed in the Bexhill maniraptoran, anterior cervical vertebrae might have been 8.5 mm long (19% longer than 7.1 mm). A neck combining 10 vertebrae with centrum lengths of between 8.5 mm and 7.1 mm (and assuming a gradation of sizes in between) produces a total neck length of c. 79.6 mm (note that this is similar to the neck length depicted in Fig. 5). Articulated maniraptoran specimens reveal total neck length to be anywhere from c. 24% ( Caudipteryx zoui ), c. 34% ( Anchiornis huxleyi ) to c. 47% ( Archaeopteryx lithographica ) of total body length (calculated from scaled skeletal reconstructions in Paul (2010)). In early short-tailed birds (such as Confuciusornis sanctus ), neck length is c. 20% of total length (tail feathers are not included in total length in any of these measures). This variability, combined with our uncertainty about the precise af fi nities of the Bexhill maniraptoran vertebra, renders it impossible to accurately estimate total length. Neverthless, if proportioned like Caudipteryx , the Bexhill maniraptoran might have a total length of c. 330 mm. If proportioned like Archaeopteryx , total length could be as low as c. 169 mm while a total skeletal length of c. 398 mm is conceivable if the animal is a short-tailed bird. While we emphasise that this exercise includes diverse possi- bilities and unknown variables (concerning number and centrum length of cervical vertebrae, total length of cervical series, and length of neck compared to animal ’ s total length), it nevertheless seems likely that the Bexhill maniraptoran was between 16 and 40 cm in total skeletal length (Fig. 5). Given the specimen ’ s adult status, this indicates that the taxon to which it belongs was one of the smallest Mesozoic dinosaurs yet reported. It may have been similar in size, or even smaller, than the most diminutive non- avialian dinosaur currently known: Anchiornis huxleyi ; a species variously estimated to have a total length of 34 cm (Xu et al., 2008) or 40 cm Paul (2010). We thank David Brockhurst for bringing this specimen to our attention and David Brockhurst and Peter and Joyce Austen for providing measurements of the section as currently exposed. Steve Chapman of Ibstock Brick Limited is thanked for providing borehole data and access to the pit. We are also grateful for the assistance of staff at Bexhill Museum and in particular the curator Julian Porter. Roger Benson and Andrea Cau are thanked for discussion and Malcolm Hart and an anonymous reviewer provided comments that improved the manuscript. Bob Loveridge, University of Portsmouth, is thanked for assistance with ...
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Citations
... Baryonyx) was a reasonable proposal in view of knowledge of Wealden spinosaurid diversity at the time but recent finds demonstrate higher diversity across the supergroup (Barker et al., 2021;Barker et al., 2022). In addition, it should be noted that these fossils come from strata spanning a time frame (∼25 million years) not considered typical for the duration of a genus-level dinosaur taxon (Naish, 2011). However, these teeth differ in several ways from the dentition of the Baryonyx walkeri holotype and we consider it plausible that they represent additional taxa (Buffetaut, 2010;Naish, 2011;Naish & Martill, 2007). ...
... In addition, it should be noted that these fossils come from strata spanning a time frame (∼25 million years) not considered typical for the duration of a genus-level dinosaur taxon (Naish, 2011). However, these teeth differ in several ways from the dentition of the Baryonyx walkeri holotype and we consider it plausible that they represent additional taxa (Buffetaut, 2010;Naish, 2011;Naish & Martill, 2007). ...
... oweni'' (Benton & Spencer, 1995;White, 1928). Allosauroid and spinosaurid teeth are also known from the Wadhurst Clay around Bexhill (Charig & Milner, 1997;Turmine-Juhel et al., 2019), as are the remains of a tiny maniraptoran (Naish & Sweetman, 2011). The enigmatic theropod Altispinax (NHMUK PV R1828) is also known from the Hastings Group of Battle (Maisch, 2016;Naish, 2011;Von Huene, 1923), located between Netherfield and Hastings. ...
Isolated spinosaurid teeth are relatively well represented in the Lower Cretaceous Wealden Supergroup of southern England, UK. Until recently it was assumed that these teeth were referable to Baryonyx , the type species ( B. walkeri ) and specimen of which is from the Barremian Upper Weald Clay Formation of Surrey. British spinosaurid teeth are known from formations that span much of the c. 25 Ma depositional history of the Wealden Supergroup, and recent works suggest that British spinosaurids were more taxonomically diverse than previously thought. On the basis of both arguments, it is appropriate to doubt the hypothesis that isolated teeth from outside the Upper Weald Clay Formation are referable to Baryonyx . Here, we use phylogenetic, discriminant and cluster analyses to test whether an isolated spinosaurid tooth (HASMG G369a, consisting of a crown and part of the root) from a non-Weald Clay Formation unit can be referred to Baryonyx . HASMG G369a was recovered from an uncertain Lower Cretaceous locality in East Sussex but is probably from a Valanginian exposure of the Hastings Group and among the oldest spinosaurid material known from the UK. Spinosaurid affinities are both quantitatively and qualitatively supported, and HASMG G369a does not associate with Baryonyx in any analysis. This supports recent reinterpretations of the diversity of spinosaurid in the Early Cretaceous of Britain, which appears to have been populated by multiple spinosaurid lineages in a manner comparable to coeval Iberian deposits. This work also reviews the British and global records of early spinosaurids (known mainly from dental specimens), and revisits evidence for post-Cenomanian spinosaurid persistence.
... The oldest known ornithomimosaurian theropods are Valanginian to Hauterivian in age. These include Nqwebasaurus from the poorly constrained Valanginian/Hautterivian upper Kirkwood Formation of South Africa (De Klerk et al., 2000;Choiniere et al., 2012;McPhee et al., 2016), the nomen dubium "Valdoraptor" from the upper Valanginian Grinstead Clay Formation, England (Naish and Sweetman, 2011;Allain et al., 2014;Austen and Batten, 2018), and Nedcolbertia from the upper Yellow Cat Member, Cedar Mountain Formation, USA (Brownstein, 2017;Joeckel et al., 2020). Hexing from the Lujiatun Unit of the Yixian Formation, China was formerly considered early Valanginian to early Barremian (e.g., Jin et al., 2012;Hunt and Quinn, 2018); however recent CA-ID-IRMS dating of the Yixian Formation produced a Barremian age (~125.8 ...
We describe the sedimentology, geochronology, and geochemistry of the Early Cretaceus Sao Khua Formation of the Khorat Basin, northeastern Thailand, and report a temporal range adjustment for its dinosaurian assemblage. Facies analysis and architectural studies reveal that sedimentation occurred within a floodplain setting fed by large meandering bedload-rich channels. Interfluve areas comprised freshwater lakes and emergent areas subject to pedogenic modification. Multiple paleosol types are identified and geochemistry is indicative of a stable humid subtropical climate regime. Based on radiometric dating of detrital zircons (via LA-ICP-MS), we interpret that the middle part of the Sao Khua Formation was deposited no later than 133.8 (±1.8) Ma (late Valanginian), and grain ages collected from the overlying lowermost Phu Phan Fm constrain sedimentation of the upper part of the Sao Khua Formation to no earlier than 132.4 (±2.0) Ma (early Hauterivian). In consideration of the Early Cretaceous regional tectonic framework, we interpret that youthful igneous zircon grains are derived from the adjacent South China-Vietnam South Borneo Volcanic Arc. We establish that the entombed dinosaur biota (including members of the Ornithomimosauria, Spinosauridae, Megaraptora, and Somphospondylia) is ~5–9 million years older than previously recognized and that these records are among the oldest known globally for these clades. Constraining the age of the Sao Khua Formation indicates that the shift from sauropod-dominated, ornithischian depauperate ecosystems of the Sao Khua Formation to iguanodontian-rich ecosystems of the Khok Kruat Formation occurred sometime between the early Hauterivian and Aptian on the Khorat Plateau.
... The Weald Sub-basin is geologically and economically important. The basin remains an extremely rich source of important vertebrate fossils including dinosaurs (e.g., Parkes, 1993;Naish and Sweetman, 2011) and has also become a major focus for unconventional hydrocarbon exploration in southeast England. ...
Petrographic datasets from sedimentary rocks are very useful for reconstructing their palaeoenvironmental settings especially when field and fossil datasets are unobtainable or inadequate. This study presents the first detailed and comprehensive petrographic study of the four formations constituting the non–marine Lower Cretaceous of the Weald Sub-basin of south-east England and employed petrographic descriptions to reconstruct their palaeoenvironmental settings. More than 120 samples were subjected to petrographic (QEMSCAN®, SEM, and thin section) analyses, which revealed that the framework composition of sediments is largely quartz-dominated (quartz arenites and subarkose) and has minor amounts of feldspar and lithics. The nature of the quartz arenites suggests that the Wealden successions were likely sourced from a stable interior craton/passive platform within a continental block and possibly from recycled flat-lying platforms such as low-lying granitic and gneissic bedrocks. The nature, maturity and the compositions of the sandstones suggest palaeoclimatic conditions were probably mildly hot and moist at the massifs and these perhaps favoured intense chemical weathering. The significant quantity of micas suggests that the Wealden sediments largely experienced very insignificant degrees of turbulence and agitation en-route depositional sites, thus yielding unwinnowed sediments. The presence of micaceous minerals, poor winnowing effect, and the general absence of diagenetic glauconite validate non-marine depositional environments. The palaeoenvironmental changes that occurred in the Lower Cretaceous in the Weald Sub-basin reflect (at least in part) palaeogeographic changes in NW Europe.
... Evidence from fossil data (e.g. Hughes, 1955;Stewart, 1978;Batten, 1982;Morter, 1984;Parkes, 1993;Feist, Lake & Wood, 1995;Horne, 1995;Jarzembowski, 1995;Goldring, Pollard & Radley, 2005;Cope, 2008;Naish & Sweetman, 2011) including work on vertebrate and invertebrate biostratigraphy (e.g. dinosaurs, charophytes, ammonites, molluscs, ostracods, insects), trace fossils and palynology have presented interpretations of the palaeo-and depositional environments similar to the ones presented in this study. ...
The Lower Cretaceous Wealden sideritic ironstones have a wide occurrence and great potential to aid the reconstruction of the depositional environments of the Weald Basin in SE England. However, mineralogical and geochemical datasets on the ironstones are scarce in the literature. Geochemical and mineralogical data on the sideritic ironstones are presented from the Wadhurst Clay Formation within the Weald Basin. The mineralogy of the ironstones was examined using a PANalytical X'Pert Pro X-ray diffractometer and PANalytical's HighScore Plus software. Elemental composition of the ironstones was measured using a PANalytical MiniPal2 ED-XRF (benchtop X-ray spectrometer). The examination of the mineralogy of the Wealden ironstones confirms the presence of early diagenetic siderites. The trace-element assemblage shows that the sideritic ironstones are chemically pure pointing to a freshwater origin. The sideritic ironstones reveal anoxic conditions and palaeo-salinity in the basin. More generally, it is suggested that the composition of the host rocks has significant controls on the composition of sideritic ironstones in sedimentary basins. This work reinforces the importance of the composition of sideritic ironstones as useful non-traditional data for understanding the depositional settings of sedimentary basins, especially when traditional datasets are not readily available or insufficient.
... This additional work was required because borehole data from the quarry company showed that Hayward had not allowed for dip in making his thickness measurements, and so the overall thicknesses calculated by him were too great. The log here (Fig. 3B, C) is based on that of Naish and Sweetman (2011). Horne (1988) reported ostracods from Ashdown Brickworks. ...
... Day (1999) reported a piece of amber from the site. However, Ashdown Brickworks is most famous for the discovery of the so-called 'Ashdown maniraptoran', a contender for the world's smallest adult dinosaur, represented in fact by a single posterior cervical vertebra of a maniraptoran theropod (Naish and Sweetman, 2011;Sweetman, 2011b). The find was also celebrated by the Royal Mail in 2013 in its special souvenir presentation pack to accompany the issue of ten first class 'dinosaur' stamps illustrated by John Sibbick (Austen, 2013). ...
... We present the fossils in sequence, describing the sharks, bony fishes, crocodyliforms, and dinosaurs. We include here only those previously undescribed fossils collected over the years by D.B. from the conglomerate bed, and do not repeat published descriptions of durophagous teeth of an albuliform bony fish (Sweetman, 2013), two forms of frog ilia and four forms of salamander vertebrae (Sweetman and Evans, 2011a), two types of scincomorph lizard dentaries and other remains (Sweetman and Evans, 2011b), the abraded cervical vertebra of a small theropod (Naish and Sweetman, 2011), and three nodosaurid ankylosaur teeth (Blows and Honeysett, 2014a). We note that additional specimens from the conglomerate bed are ...
Ashdown Brickworks, near Bexhill, East Sussex, has produced a large number of vertebrate fossils from the Wadhurst Clay Formation, part of the Wealden Supergroup (Hastings Group; Valanginian; Lower Cretaceous). Here we describe the microvertebrate fauna of the ‘conglomerate bed’, representing a rich sample of taxa. While most of the recovered teeth and bones are abraded, some heavily, most can be identified to species level. The taxa include four species of hybodont sharks (Egertonodus basanus, Planohybodus ensis, Polyacrodus parvidens, P. brevicostatus), three taxa of bony fishes (an unidentified Lepidotes-like semionotiform, the pycnodontiform Ocloedus, and an albuliform), three taxa of crocodyliforms (the goniopholid Hulkepholis, a bernissartiid, and the atoposaurid Theriosuchus), and the theropod dinosaurs Baryonyx and an allosauroid. Sediments of the Wadhurst Clay Formation as a whole indicate freshwater to very slightly brackish-water environments of deposition, and the mainly aquatic time-averaged mixture of fishes and tetrapods recovered from the ‘conglomerate bed’, together with isolated terrestrial species, confirms this interpretation.
... Kirkaldy, 1939Kirkaldy, , 1947Worssam, 1972;Allen, 1975Allen, , 1981Stewart, 1981aStewart, , b, 1983Lake and Shephard-Thorn, 1987) and fossil data (e.g. Hughes, 1955;Stewart, 1978;Batten, 1982;Morter, 1984;Parkes, 1993;Feist et al., 1995;Horne, 1995;Jarzembowski, 1995;Cope, 2008;Naish and Sweetman, 2011). Work on fossils which used vertebrate and invertebrate biostratigraphy (e.g. ...
... The Cretaceous remains a rich source of vertebrate remains (e.g. Parkes, 1993;Pereda-Suberbiola, 1993;Tang et al., 2001;Naish, 2003;Sweetman, 2006;Taylor and Naish, 2007;Sweetman, 2008;Naish and Sweetman, 2011;Garrido and Salgado, 2015;Xing et al., 2016). All these changes ensured that sedimentation occurred in non-marine conditions such as in the Lower Cretaceous of southeast England (e.g. ...
Palaeoenvironmental reconstructions of the Wealden (Lower Cretaceous) in southeast England have been previously based mainly on field and fossil data. This study presents new interpretations of multi-proxy data sets such as sandstone petrography, elemental geochemistry and sideritic ironstones, supplemented by outcrop and clay mineralogical data. The dominance of quartz arenites, kaolinite and thorium and the presence of Zr in the sediments suggest that they were sourced mainly from granitic and/or gneissic rocks. Materials from metamorphic sources are secondary in abundance. The mineral and textural maturity of the sediments coupled with inferred short transport distances suggests reworking from older sources. Palaeoclimatic conditions in the source areas were generally warm and humid in nature, which supported an intensive weathering regime. The nature of the sediments suggests they may have been sourced directly or indirectly from a stable craton. The lithology, facies, sedimentary structures, architecture and gamma ray data confirm the freshwater origin of the sediments. Redox-sensitive trace elements such as Mo, U, V and Co suggest anoxic conditions in the basin. The results presented in this paper reinforce the importance of integrating multi-proxy data sets for interpreting the palaeoenvironmental conditions of sedimentary basins: when traditional data sets such as field and fossil data are not readily available or insufficient to enable adequate interpretations, the integration of petrographic, mineralogical and geochemical data sets may prove to be useful in similar palaeoenvironmental studies. Copyright
... If the Minisauripus trackmaker is indeed a small adult theropod, these ichnofossils could contribute to our knowledge of theropod palaeobiology and fill a gap in the body fossil record. Besides the smallest non-avialian theropod Anchiornis (troodontid), some juveniles or subadults such Epidendrosaurus (Naish and Sweetman, 2011) and Epidexipteryx (Zhang et al., 2008) have total skeletal lengths of only about 16 cm and 25 cm, respectively. The Ashdown maniraptoran, from England, is thought to have had a body length between only 16 and 40 cm (Naish and Sweetman, 2011). ...
... Besides the smallest non-avialian theropod Anchiornis (troodontid), some juveniles or subadults such Epidendrosaurus (Naish and Sweetman, 2011) and Epidexipteryx (Zhang et al., 2008) have total skeletal lengths of only about 16 cm and 25 cm, respectively. The Ashdown maniraptoran, from England, is thought to have had a body length between only 16 and 40 cm (Naish and Sweetman, 2011). Many other non-avialian theropods are known from specimens shorter than 100 cm, such as Parvicursor (39 cm) (Karhu and Rautian, 1996), Sinosauropteryx (68 cm) (Chen et al., 1998), Mei (53 cm) (Xu and Norell, 2004), Mahakala (70 cm) (Turner et al., 2007), and the oviraptorosaur Yulong ("chicken-sized",~70 cm) (Lü et al., 2013). ...
... Early Cretaceous alvarezsaurids have not yet been found in China, although Haplocheirus is known from the Upper Jurassic Shishugou Formation in northwestern China (Choiniere et al., 2010). Scansoriopterygids are thought to have been largely arboreal (Naish and Sweetman, 2011) and, besides being rare, most occur in Middle Jurassic deposits. Among them Epidendrosaurus (IVPP V12653) (Zhang et al., 2002) has poorly preserved feet, and the feet of Epidexipteryx (IVPP V15471) (Zhang et al., 2008) are not known. ...
... life position in a generalised maniraptoran silhouette.(from Naish andSweetman 2011) ...
Recognition by the Royal Mail of Europe’s smallest adult dinosaur found at Ashdown Brickworks, Bexhill (Wealden).
Reference: Austen, P.A., 2013. David Brockhurst – Royal Mail’s Stamp of Approval! Hastings & District Geological Society Journal 19, 32–33.
... It incorporates two pits exploiting argillaceous and arenaceous strata in the mid-Valanginian part (Gallois and Worssam, 1993) of the Hastings Group. Of these, Crowborough Pit has yet to yield vertebrate fossils, but a number of strata in the more northerly Pevensey Pit, which is in the upper part of the Wadhurst Clay Formation and the lowest part of the overlying Tunbridge Wells Sand Formation (Fig. 2), have yielded a diverse assemblage of aquatic and terrestrial vertebrates (Naish and Sweetman, 2011). The clay known locally as the 'lower clay' contains two bone bed horizons ( Fig. 2) representing channel lags of variable lateral thickness and extent. ...
... It is the most palaeontologically diverse, yielding abundant bones, bone fragments, teeth, scales, and other isolated elements. These represent chondrichthyan and osteichthyan fishes, salamanders, frogs, aquatic and terrestrial lizards, turtles, crocodyliforms, pterosaurs, and dinosaurs (Naish and Sweetman, 2011). The lowermost of the bone beds is known locally as the 'turtle bed' (Fig. 3). ...
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... While the small pterosaurs and theropod dinosaurs discovered at Liaoning are often articulated and near-complete (e.g. [42][43][44][45][46]), those from the Wealden typically consist of isolated bones [47,48]. In conclusion, the western European Lower Cretaceous pterosaur assemblage is most reasonably interpreted as strongly biased by the absence of sites where pterosaurs were both taxonomically diverse, and readily incorporated into the sediment record: a position that agrees with quantitative studies of pterosaur diversity across time [49]. ...
... This condition is reversed in many other pterosaurs [21,[50][51][52][53][54][55] ( Figure 8B). [50]; C Coloborhynchus spielbergi, after Veldmeijer [48]; D, Kimmeridgian dsungaripterid DFMMH/FV500, after Fastnacht [53]; E, Germanodactylus rhamphastinus, after Wellnhofer [66]; F, Pterodactylus antiquus, after Wellnhofer [32]. See text for accompanying description of characters and their primitive (0) and derived (1) states. ...
... Pterosaur pelves in dorsal view showing different states of characters 9 and 20-22, as illustrated by exemplar taxa. A, Rhamphorhynchus muensteri, after Wellnhofer[32]; B, Coloborhynchus spielbergi, after Veldmeijer[48]. See text for accompanying description of characters and their primitive (0) and derived (1) states. Scale bar = 10 mm. ...
Background
Pterosaurs have been known from the Cretaceous sediments of the Isle of Wight (southern England, United Kingdom) since 1870. We describe the three-dimensional pelvic girdle and associated vertebrae of a small near-adult pterodactyloid from the Atherfield Clay Formation (lower Aptian, Lower Cretaceous). Despite acknowledged variation in the pterosaur pelvis, previous studies have not adequately sampled or incorporated pelvic characters into phylogenetic analyses.
Methodology/Principal Findings
The new specimen represents the new taxon Vectidraco daisymorrisae gen. et sp. nov., diagnosed by the presence of a concavity posterodorsal to the acetabulum and the form of its postacetabular process on the ilium. Several characters suggest that Vectidraco belongs to Azhdarchoidea. We constructed a pelvis-only phylogenetic analysis to test whether the pterosaur pelvis carries a useful phylogenetic signal. Resolution in recovered trees was poor, but they approximately matched trees recovered from analyses of total evidence. We also added Vectidraco and our pelvic characters to an existing total-evidence matrix for pterosaurs. Both analyses recovered Vectidraco within Azhdarchoidea.
Conclusions/Significance
The Lower Cretaceous strata of western Europe have yielded members of several pterosaur lineages, but Aptian pterosaurs from western Europe are rare. With a pelvis length of 40 mm, the new animal would have had a total length of c. 350 mm, and a wingspan of c. 750 mm. Barremian and Aptian pterodactyloids from western Europe show that small-bodied azhdarchoids lived alongside ornithocheirids and istiodactylids. This assemblage is similar in terms of which lineages are represented to the coeval beds of Liaoning, China; however, the number of species and specimens present at Liaoning is much higher. While the general phylogenetic composition of western European and Chinese communities appear to have been approximately similar, the differences may be due to different palaeoenvironmental and depositional settings. The western Europe pterodactyloid record may therefore be artificially low in diversity due to preservational factors.
