Theropods of the British Isles Part I

The bipedal theropods represent the most diverse group of dinosaurs including all the meat-eating ones as well as some omnivorous and herbivorous forms. Primitive theropods include the coelophysoids (small, slender and lightly built dinosaurs that thrived worldwide during the Late Triassic, and for which the best known representative is the North American Coelophysis), the ceratosaurs (including forms such as Ceratosaurus and Carnotaurus) and the tetanurans. The last group contains the vast majority of the theropods and its members are characterized among other things by a rigid tail and the total loss of the fourth and fifth digits in their hands. Megalosaurs (i.e. Megalosaurus) are early tetanurans while Spinosaurs (i.e. Spinosaurus and co) are possibly related to them. Later tetanurans are the allosauroids (large predators such as Allosaurus and Carcharodontosaurus) and the coelurosaurians, which in turn include the tyrannosauroids (such as Tyrannosaurus), the ornithomimosaurs (the ostrich-mimic forms such as Struthiomimus and Ornithomimus) and the maniraptorans. The maniraptorans with their modified wrist and generally large hands are represented by the birds (where the hands became wings) and all their closest relatives, such as the oviraptosaurs (Oviraptor and co), the deinonychosaurs (Velociraptor and co).

Fig 1.- Small coelophysoids lived during the Late Triassic in Great Britain.

Late Triassic Theropods

During the Upper Carnian (~ 220 MYA) of Scotland lived Saltopus elginensis Huene 1910, known from a poorly preserved partial skeleton including dorsal, sacral and caudal vertebrae and fragments of fore and hind limbs (BMNH R3915) found in the Lossiemouth Sandstone Formation, near Elgin, Morayshire. The exact affinities of the animal have been debated. It was either a primitive theropod or a more ancestral dinosauriform.

Theropods were definitely present during the Late Triassic period in the British Isles as proven by the discovery of fragments in the fissure fills of southern Wales. A pelvis, femur and dorsal vertebrae (BMNH PV RU P77/1 and RUP 76/1) from Pant-y-ffynon, Wales of Norian age (~210 MYA), were possibly from a coelophysoid.

The dubious ‘Zanclodon’ cambrensis Newton, 1899 of Rhaetian age (~200 MYA) is known from the mold of a large left dentary with teeth (BGS 6532/BMNH R2912) from Glamorganshire, Wales (Lilstock Fm). This one might be another coelophysoid.

Fig 2.- Larger coelophysoid such as Sarcosaurus roamed the Early Jurassic of England.

Early Jurassic Theropods

In the early Jurassic, coelophysoids are represented by the shadowy Sarcosaurus. The type species, Sarcosaurus woodi Andrews, 1921 is known from a partial pelvis, femur and vertebra (BMNH 4840/1) from Leicestershire (Lias Fm) of Early Sinemurian age (which probably is actually of earlier Late Rhaetian or Hettangian age, ~198-200 MYA). A second species, Sarcosaurus andrewsi Huene, 1932 (= Magnosaurus woodwardi) is based on a partial right tibia (BMNH R3542), originally reported by Woodward in 1908 from Warwickshire of Hettangian age (~198 MYA). Sarcosaurus was a quite large coelophysoid with an estimated length of about 3.5 m.

From the Sinemurian (~192 MYA) Upper Broadford Beds Formation of the Isle of Skye (Scotland) came an incomplete right tibia (NMS.G.1994.10.1), interpreted as belonging to a small theropod, probably another coelophysoid (Benton et al., 1995).

A partial hindlimb from Charmouth, Dorset  (BMNH 39496) that was described by Owen (1861) alongside remains of the ornithischian Scelidosaurus harrisonii was reported from the Lower Lias (Hettangian-Sinemurian). This one was found to be comparable to a megalosaur and would therefore be an early member of this group of large theropods that will dominate the Middle Jurassic period.

Finally, a tooth (BMNH 41352) from the Lias group of Lyme Regis, named ‘Megalosaurus’ lydekkeri von Huene, 1926 (= Magnosaurus lydekkeri), is from an indeterminate theropod.

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)


References:

C. W. Andrews. 1921. On some remains of a theropodous dinosaur from the Lower Lias of Barrow-on-Soar. Annals and Magazine of Natural History, series 9 8:570-576

M.J. Benton, D.M. Martill & M.A. Taylor, 1995. The first Lower Jurassic dinosaur from Scotland: limb bone of a ceratosaur theropod from Skye. Scottish Journal of Geology, 31, 177–182.

F. v. Huene. 1910. Ein primitiver Dinosaurier aus der mittleren Trias von Elgin [A primitive dinosaur from the Middle Trias of Elgin]. Geologie und Paläontologie Abhandlungen (n.s.) 8(6):317-322.

D. Naish and D. M. Martill. 2007. Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: basal Dinosauria and Saurischia. Journal of the Geological Society, London 164:493-510.

O. W. M. Rauhut and A. Hungerbühler. 2000. A review of European Triassic theropods. GAIA 15:75-88.

Sauropods of the British Isles Part III

Fig 1.- Rebbachisaurids were present on the Isle of Wight during the Early Cretaceous.

Sauropods from the Early Cretaceous (part II)

The Wessex Formation of the Isle of Wight

The Wessex formation on the Isle of Wight of Barremian age (~ 127 MYA) has a number of sauropod remains, all very fragmentary but enough to point to a high degree of diversity for this group in the British Isles during the Early Cretaceous.

The presence of Diplodocids is scarce if ever they were present at all. A chevron has been described by Alan Charig (1980) as belonging to a diplodocid, but the identification has since then been disputed.  The presence of Rebbachisaurids, on the other hand, is well attested and is represented by isolated bones, including a characteristic scapula [= shoulder blade]  (MIWG 6544), tail vertebra (MIWG 5384) and possibly teeth.  From these scant remains, it appears that the unnamed British representative of this group is most closely related to the Spanish Demandasaurus and the African Nigersaurus (see my previous post about it).

Brachiosaurids were also certainly there and remains are represented by  ‘Pleurocoelus’ valdensis Lydekker, 1889, based on teeth, dorsal and caudal vertebra found near Cuckfield, East Sussex, Hastings beds and on the Isle of Wight. Usually considered to be dubious, Pleurocoelus valdensis is, according to Ruiz-Omeñaca & Canudo (2005), a perfectly valid taxon that was also present in the Iberian Peninsula. Other possible brachiosaurid remains include  ‘Ornithopsis’ eucamerotus Hulke, 1882, based on a set of pelvis bones (BMNH R97), an unnamed taxon evidenced by a single large cervical vertebra (MIWG 7306) that might have belonged to the largest dinosaur of Europe (Naish et al., 2004), and Eucamerotus foxi Blows, 1995, described from a neural arch (BMNH R2522), two dorsals (BMNH R89-90) and another dorsal from a juvenile specimen (BMNH R2524). Oplosaurus armatus Gervais, 1852, is based on a large tooth (BMNH R964) that may belong to a brachiosaurid, but more recent analysis indicated it is more probably from a camarasaurid (Canudo et al., 2002). Chondrosteosaurus gigas Owen, 1876 is known from two neck vertebrae (BMNH 46869 & BMNH 46870) and is probably a basal titanosauriform, although we cannot say if it is a camarasaurid or a brachiosaurid.

Fig 2.- The specialized Titanosaurs were the dominant group of sauropods at the end of the Early Cretaceous.

The most evolved group of sauropods, the titanosaurs, is represented by Iuticosaurus valdensis LeLoeuff et al., 1993, known from 2 tail vertebrae (BMNH R146a & BMNH 151).

Finally, two dubious taxa are indeterminate sauropods: the Isle of Wight ‘Ornithopsis’ hulkei dorsal vertebra (BMNH R28632) was renamed Bothriospondylus elongatus by Owen in 1875 and ‘Ornithopsis’ eucamerotus by Hulke in 1882. Chondrosteosaurus magnus Owen, 1876 is based on a single partial vertebra (BMNH R98).

The Lower and Upper Greensand

The Lower Greensand Group of Aptian age (~120 MYA) delivered a pelvis and associated sacrum (BMNH R12713) from Luccombe Chine, Isle of Wight of a titanosauriform of some sort (Stroh, 1949, Blows, 1995). Also from the Lower Greensand came Dinodocus mackesoni Owen, 1884, based on a humerus (BMNH 14695) from Hythe, Kent. Possibly another indeterminate titanosauriform.

The Upper Greensand formation (Albian-Cenomanian age, ~112 MYA) in southeastern England bears a few sauropod remains, which are the youngest in the British Isles and all belong to titanosaurs. “Titanosaurus” lydekkeri Huene, 1929 (= Iuticosaurus lydekkeri), based on a vertebra (BMNH 32390) found on the Isle of Wight, was synonymized with Macrurosaurus semnus by McIntosh, 1990, but generally considered a nomen dubium.  Macrurosaurus semnus Seeley, 1876 is based on a set of 25 caudal vertebrae (SM B55630) and 15 more various bits found in Cambridgeshire and of Cenomanian age, and is an indeterminate titanosaur.

This concludes our tour of the sauropods of the British Isles.


Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)


References:


W. T. Blows. 1995. The Early Cretaceous brachiosaurid dinosaurs Ornithopsis and Eucamerotus from the Isle of Wight, England. Palaeontology 38(1):187-197


W. T. Blows. 1998. A review of Lower and Middle Cretaceous dinosaurs of England. In S. G. Lucas, J. I. Kirkland, and J. W. Estep (eds.), Lower and Middle Cretaceous Terrestrial Ecosystems, New Mexico Museum of Natural History and Science Bulletin 14:29-38


J. Le Loeuff, E. Buffetaut, M. Martin, V. Martin, and H. Tong. 1993. Découverte d'Hadrosauridae (Dinosauria, Ornithischia) dans le Maastrichtian des Corbières (Aude, France) [Discovery of Hadrosauridae (Dinosauria, Ornithischia) in the Maastrichtian of Corbières (Aude, France)]. Comptes Rendus de l'Academie des Sciences, Paris, Série II 316:1023-1029


R. Lydekker. 1889. Note on some points in the nomenclature of fossil reptiles and amphibians, with preliminary notices of two new species. Geological Magazine, decade 3 6:325-326


R. Lydekker. 1893. On a sauropodous dinosaurian vertebra from the Wealden of Hastings. Quarterly Journal of the Geological Society of London 49:276-280


J. S. McIntosh. 1990. Sauropoda. In D. B. Weishampel, H. Osmólska, and P. Dodson (eds.), The Dinosauria. University of California Press, Berkeley 345-401


A. G. Melville. 1849. Notes on the vertebral column of the Iguanodon. Philosophical Transactions of the Royal Society of London 139:285-300.


D. Naish, D.M. Martill, D. Cooper & K.A. Stevens, 2004. Europe’s largest dinosaur? A giant brachiosaurid cervical vertebra from the Wessex Formation (Early Cretaceous) of southern England. Cretaceous Research, 25, 787–795.


D. Naish and D. M. Martill. 2007. Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: basal Dinosauria and Saurischia. Journal of the Geological Society, London 164:493-510


R. Owen. 1876. Monograph on the fossil Reptilia of the Wealden and Purbeck formations. Supplement no. VII. Crocodilia (Poikilopleuron) and Dinosauria? (Chondrosteosaurus). [Wealden.]. The Palaeontographical Society, London 1876:1-7


J. I. Ruiz-Omeñaca and J. I. Canudo. 2005. "Pleurocoelus" valdensis Lydekker 1889 (Saurischia, Sauropoda) en el Cretácico Inferior (Barremiense) de la Península Ibérica ["Pleurocoelus" valdensis Lydekker 1889 (Saurischia, Sauropoda) in the Lower Cretaceous (Barremian) of the Iberian Peninsula]. Geogaceta 38:43-45


H. G. Seeley. 1870. On Ornithopsis, a gigantic animal of the pterodactyle kind from the Wealden. Annals and Magazine of Natural History, series 4 5:279-283.


H. G. Seeley. 1876. On Macrurosaurus semnus (Seeley), a long tailed animal with procoelous vertebrae from the Cambridge Upper Greensand, preserved in the Woodwardian Museum of the University of Cambridge. Quarterly Journal of the Geological Society of London 32:440-444


M. P. Taylor and D. Naish. 2007. An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England. Palaeontology 50(6):1547-1564.

Sauropods of the British Isles Part II

Fig 1.- A hypothetical reconstruction of Pelorosaurus conybeari.

Sauropods from the Early Cretaceous (I)

The Hastings Beds

The Hastings Beds in East Sussex, of Berriasian-Valanginian age (~140 MYA), bore a number of fragmentary sauropod remains. A set of tail vertebrae and chevrons (BMNH R2544–2555) found near Cuckfield, East Sussex, were originally described alongside some iguanodont remains by Richard Owen as Cetiosaurus brevis (Owen, 1842). Alexander Melville, noting Owen’s mistake, renamed the sauropod vertebrae Cetiosaurus conybeari (Melville, 1849). A year later, Gideon Mantell realizing that they belong to a animal quite distinct from Cetiosaurus, changed the name into Pelorosaurus conybeari (Mantell, 1850), and added to the description, a humerus (BMNH 28626) found a few meters away from the original vertebrae material. This succession of attribution changes resulted in a taxonomical nightmare for the later generation scientists. Technically, the name C. brevis has indeed seniority over Pelorosaurus conybeari and should be considered to be the valid name. However, with the invalidation of C. medius (see Part I), C. brevis would also be the type species of the genus Cetiosaurus, making its use for the Middle Jurassic C. oxoniensis, which turned out to be a very different animal quite problematic (As far as I know, the petition to ICZN to make C. oxoniensis the type species of Cetiosaurus is still pending) . As for the general aspect of what Pelorosaurus may have looked like, all that can be said from the scant remains is that it was a brachiosaurid and would probably resemble to a smaller version of the North American Late Jurassic Brachiosaurus, with a possible size of some 15 meters in length.

Not much can be said about the three other named sauropods of the Hastings Beds. ‘Pelorosaurus’ becklesi Mantell, 1852 (= Morosaurus becklesii Marsh, 1889) based on a humerus (BMNH R1868), ulna, radius and skin impressions, probably belong to a different animal than Pelorosaurus conybeari. It may also be a brachiosaurid unless it is a more advanced titanosaur. ‘Ornithopsis’ hulkei Seeley, 1870 is based on two dorsal vertebrae, one from East Sussex (BMNH R2239), the other from the Isle of Wight Wessex Formation (BMNH R28632), and originally thought to belong to a pterosaur (thus the genus name which means “bird likeness”). Owen (1876), however, split the two findings, naming the East Sussex vertebrae Bothriospondylus magnus, then Chondrosteosaurus magnus. The remains have no distinct characteristics apart the fact that they belong to a sauropod of some sort so the name should be considered dubious.  Xenoposeidon proneneukos Taylor & Naish, 2007 is based on a single partial back vertebra (BMNH R2095). Xenoposeidon’s vertebra is so unique that its affinities within the Sauropods are quite uncertain.


Next will be the sauropods from the Wessex Formation.

 

 

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

References:

G. A. Mantell. 1850. On the Pelorosaurus; an undescribed gigantic terrestrial reptile, whose remains are associated with those of Iguanodon and other saurians in the strata of the Tilgate Forest, in Sussex. Philosophical Transactions of the Royal Society of London 140(16):379-390.

A. G. Melville. 1849. Notes on the vertebral column of the Iguanodon. Philosophical Transactions of the Royal Society of London 139:285-300.

D. Naish and D. M. Martill. 2007. Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: basal Dinosauria and Saurischia. Journal of the Geological Society, London 164:493-510.

R. Owen. 1876. Monograph on the fossil Reptilia of the Wealden and Purbeck formations. Supplement no. VII. Crocodilia (Poikilopleuron) and Dinosauria? (Chondrosteosaurus). [Wealden.]. The Palaeontographical Society, London 1876:1-7.

H. G. Seeley. 1870. On Ornithopsis, a gigantic animal of the pterodactyle kind from the Wealden. Annals and Magazine of Natural History, series 4 5:279-283.

M. P. Taylor and D. Naish. 2007. An unusual new neosauropod dinosaur from the Lower Cretaceous Hastings Beds Group of East Sussex, England. Palaeontology 50(6):1547-1564.

Sauropods of the British Isles I

 Fig 1.- Reconstruction of Cetiosaurus oxoniensis.


Sauropods, the long-necked, long-tailed giant herbivorous dinosaurs, are better known in popular imagination by their North American representatives, Diplodocus and Brachiosaurus. Sauropods are divided into a number of families and groups that can be distinguished from details of their skeletal anatomy and teeth. Among the most primitive families, the Melanosaurids were only recently (Yates, 2007) recognized as early sauropods instead of being placed within more basal sauropodomorphs. Cetiosaurids are an ill-defined group of primitive sauropods built around the British Cetiosaurus and perhaps including other members such as the Chinese club-tailed Shunosaurus. The Turiasaurs form a recently erected clad (Royo-Torres et al., 2006) of gigantic sauropods so far restricted to southernwestern Europe. The Diplodocoids regroup three distinct families, the highly specialized rebbachisaurids, the relatively short-necked, tall-spined dicraeosaurids and the long and slender diplodocids. The Macronarians are characterized by their erect neck posture and comparatively large nasal opening (nostrils) on their head. They are subdivided into the camarasaurids (primitive macronarians), brachiosaurids and titanosaurs, the last two families including the largest and heaviest creatures that ever walked the earth.

Numerous remains of sauropods were found in the British Isles, but the vast majority of the named genera and species are based on very scant material with no unique characteristics making them nomina dubia (dubious names). However, they can generally be diagnosed at higher group levels, showing that the British Isles were once home to a diverse fauna of sauropods that include the earliest members of such groups as the Diplodocoidea and Rebbachisauridae. Let’s meet them in stratigraphical chronological order (please note that the list of fossils mentioned is in no way exhaustive)...

We already met in a previous post, Camelotia borealis from the Westbury Formation of Late Triassic Rhaetian age, which was possibly an early sauropod, unless it is a large representative of something more basal.

Sauropods from the Middle Jurassic

The first definite British sauropod remain comes from the Middle Jurassic Aalenian stage (~175 MYA). It consists of a partial left pubis and ischium (BMNH R9472) of the Northampton Sands Formation, from Harleston, Northamptonshire (Reid, 1984). This unnamed taxon was possibly a brachiosaurid or a titanosaur making it either way the earliest recorded macronarian in the world.

Fig 2.- Britain has some remains belonging to the earliest known macronarian.

Next come large collection of bones from the Forest Marble Formation of Bathonian age (~165 MYA).  The most famous fossil of this formation is the primitive sauropod Cetiosaurus (“whale lizard”). Cetiosaurus is one of the earliest dinosaurs to receive a name and, as it happened to many genera described in the early days of paleontology, it became a so-called wastebasket taxon, with up to 13 species described in the British Isles alone, ranging temporally from the Middle Jurassic to the Early Cretaceous. In a general revision of the genus, Upchurch and Martin (2003) finally recognized the only Cetiosaurus oxoniensis Phillips, 1871 from the Forest Marble as a valid species.  Cetiosaurus is known from various postcranial elements coming from different places in Oxfordshire (OUM J13605-13613, 13615-13616, 13619-13688, 13899), Northamptonshire and Gloucestershire. A partial skeleton from the slightly older Bajocian (~ 170 MYA) Rutland Formation of Rutland (LCM G468.1968) is also being assigned to C. oxoniensis, as well as a partial braincase (OUM J13596) and a tooth (OUM J13597) found at the same location than the Oxfordshire Blechington specimen. This large, perhaps 20 meters long sauropod exhibits a number of primitive features in the structure of their vertebrae.  Due to the fragmentary nature of the remains, many aspects of this animal, such as the skull, are almost totally unknown, despite it being the best-known sauropod of Great Britain.

Cetiosaurus medius Owen, 1842 known from 11 caudal centra (OUM J13693–13703) and other various bits found in Oxfordshire, Gloucestershire, Buckinghamshire, is non-diagnostic. Since C. medius is generally considered as the type species of Cetiosaurus, its invalidation would render the naming of C. oxoniensis problematic. A petition has therefore been filed to ICZN to make C. oxoniensis the new type species for the genus. Cardiodon rugulosus described by Owen in 1844, out of a single, now lost, tooth unearthed near Bradford-on-Avon, Wiltshire, may be the same animal than Cetiosaurus, but it was also been proposed to be a Turiasaur.

Two other distinct taxa are known from the Forest Marble Formation: one is ‘Cetiosaurus’ glymptonensis  Phillips, 1871 (= Cetiosauriscus glymptonensis (Phillips, 1871) McIntosh, 1990) described from a series of 9 caudal vertebrae (OUM J13750-13758) found in Glympton, Oxfordshire. It was possibly a diplodocoid, making it the earliest known member of this group in the world. However, due to the lack of unique characters, C. glymptonensis is generally considered to be a nomen dubium (Barrett et al., 2003). The as dubious Bothriospondylus robustus  Owen, 1875 = Marmarospondylus robustus) from Bradford-on-Avon, Wiltshire, is known from a single dorsal vertebra (BMNH R22428) and might be a macronarian.

Another possible macronarian has been described from the similar age Kilmaluag Formation (late Bathonian) of Strathaird, Isle of Skye, Western Scotland: it is a tooth (NMS G 2004.31.1), one of the very rare dinosaurian remains found in Scotland. This fossil is distinctly different from both Cetiosaurus and Cardiodon (Barrett, 2006).

From the Lower Callovian age (~163 MYA) Kellaways formation, comes ‘Ornithopsis’ leedsi Hulke, 1887, known from vertebrae, ribs and pelvic fragments (BMNH R1984-1988), found near Peterborough, Cambridgeshire. This was probably a Brachiosaurid. The name Ornithopsis originally refers to the undeterminate O. hulkei from the Early Cretaceous (see part II), which would mean that O. leedsi probably requires a new generic name.

Fig 3.- other remains from britain are from the earliest known diplodocoid.

In the overlying Oxford Clay Formation (Middle Callovian – Early Oxfordian age, ~161 MYA), other materials from Peterborough, including a series of vertebrae (BMNH R.3078) were confusingly also referred to ‘Ornithopsis’ leedsi by Woodward in 1905. But Charig concluded in 1980 that the bones belong to a quite different animal, a diplodocid, and give them the name ‘Cetiosauriscus’ stewarti.


Sauropods from the Late Jurassic

From the Kimmeridge Clay Formation of Kimmeridgian age (~153 MYA), comes Duriatitan humerocristatus (Lydekker, 1888) (Initially named 'Cetiosaurus' humerocristatus) based on a gracile left humerous (BMNH R44635) from Weymouth, Dorset (Hulke, 1874). It was determined to belong to a Titanosauriform (Barrett et al., 2010). The dubious ‘Ornithopsis’ manseli  (Lydekker, 1888) (= ‘Ischysaurus’ manseli ), based on a partial humerus ((BMNH 41626), also from Dorset, may belong to the same animal. The same can be said of Bothriospondylus suffosus Owen, 1875 from Wiltshire, known from dorsal and sacral vertebrae (BMNH R44592-5: 4).

Some non-diagnostic vertebrae, limb elements and dermal scutes found near Stretham, Cambridgeshire (BMNH 32498-99) were described as Gigantosaurus megalonyx Seeley, 1869 and belong to a sauropod of some sort. Also from the Kimmeridgian, ‘Cetiosaurus’ longus Owen, 1842 based on a single dorsal and caudal centra (OUM J13617) from the Portland Stone Formation at Garsington, Oxfordshire, is an indeterminate sauropod.


Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

References:

P. M. Barrett. 2006. A sauropod dinosaur tooth from the Middle Jurassic of Skye, Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 97:25-29

P. M. Barrett, R. B. J. Benson, and P. Upchurch. 2010. Dinosaurs of Dorset: Part II, the sauropod dinosaurs (Saurischia, Sauropoda) with additional comments of the theropods. Proceedings of the Dorset Natural History and Archaeological Society 131:113-126

A. J. Charig. 1980. A diplodocid sauropod from the Lower Cretaceous of England. In L. L. Jacobs (ed.), Aspects of Vertebrate History: Essays in Honor of Edwin Harris Colbert. Museum of Northern Arizona Press, Flagstaff 231-244

J. W. Hulke. 1874. Note on a very large saurian limb-bone adapted for progression upon land, from the Kimmeridge Clay of Weymouth, Dorset. Quarterly Journal of the Geological Society of London 30:16-17

D. Naish and D. M. Martill. 2007. Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: basal Dinosauria and Saurischia. Journal of the Geological Society, London 164:493-510

R. Owen. 1841. Description of a portion of the skeleton of the Cetiosaurus, a gigantic extinct saurian reptile occurring in the Oolitic formations of different portions of England. Proceedings of the Geological Society of London 3, part 2(80):457-462

R. Owen. 1875. Monographs on the fossil Reptilia of the Mesozoic formations. Part II. (Genera Bothriospondylus, Cetiosaurus, Omosaurus). The Palaeontographical Society, London 1875:15-93

M. D. Jones. 1970. Cetiosaurus oxoniensis, Phillips J. A middle Jurassic sauropod from Rutland, England. Leicester Literary and Philosophical Society 64:144-150

J. Phillips. 1871. Geology of Oxford and the Valley of the Thames. Clarendon Press, Oxford 1-523.

P. M. Upchurch and J. Martin. 2003. The anatomy and taxonomy of Cetiosaurus (Saurischia, Sauropoda) from the Middle Jurassic of England. Journal of Vertebrate Paleontology 23(1):208-231.

Spinops: my very own personal paleoart portfolio

Once upon a while, scientists came with really catchy dinosaur names. Examples of cool generic nomina include Dracorex (the “dragon king”), Raptorex (the “king thief”), Cryptoraptor (the “hidden thief”), Brontosaurus (the “thunder lizard”) and Diabloceratops (the “devil horn face”). Shame that some of those critters turn out to be invalid and too bad scientific names cannot be recycled! Others are just plain awful. For (at least) English speakers, there are real tongue twisters such as Bruhatkayosaurus (fortunately this one might just be a hoax [great post from Matt Martyniuk]), Futalognkosaurus (do I even get the spelling right?), Krzyzanowskisaurus, Naashoibitosaurus. 

 Among the recently allocated names, Spinops is one of the best I came across: it is short, easy to remember and combines those of two of the most iconic dinosaurs, Spinosaurus and Triceratops. Good reasons to use it for my new paleoart portfolio website, before somebody else get the same idea… 

I’ve just started, and so far it has only some 140 images in it as I have to go through all my folders and hard drives to check what I've done since 2007. The nice thing about this online portfolio is that it is wholly searchable (type for instance “plesiosaur” if you want to see these only), and illustrations can be arranged by group or production date. Have a look…

Late Triassic Dinosaurs of the British Isles

Fig 1.- Thecodontosaurus antiquus.

The British Late Triassic land vertebrate fauna is essentially known from disarticulated bones found in various Mesozoic fissure fills of underlying Lower Carboniferous limestone in England and Wales. The fauna include the very first British dinosaurs of Rhaetian age (~ 200 MYA), living alongside a variety of reptiles including sphenodontians, running crocs of the sphenosuchian group (such as Terrestrisuchus gracilis), trilophosaurs (such as Variodens inopinatus), and gliding lizards such as Kuhneosaurus. Dinosaurs were not the dominant group that will rule the land during the Jurassic and Cretaceous periods, constituting only about 10% of the vertebrate fauna found in those fissure fills. One archosaurian form, named Agnostiphys cromhallensis from the Cromhall Quarry in Avon, has clearly some dinosaurian characteristics. It was described in 2002 by N.C. Fraser and co-workers based on a left ilium, left maxilla, a right humerus, a pair of astragalus and an isolated tooth. The validity of the taxon is disputed as the different parts may come from different animals (thus making the original description a chimera) and the remains are too scant to decide if it was an archosaur closely related to dinosaurs or a true primitive dinosaur, possibly a herrerasaur.

Sauropodomorphs from Rhaetian fissure fills: Thecodontosaurus, Asylosaurus, Pantydraco

The other dinosaurian remains of the Rhaetian fissure fillings all belong to basal sauropodomorphs, the group of saurischian dinosaurs which will eventually lead to the Jurassic and Cretaceous long-necked herbivorous giants called Sauropods to which the North American Brachiosaurus, Diplodocus and Apatosaurus are the most popular members. From a locality known as Durdham Down, Clifton, near Bristol in England, hundreds of bones have been excavated in the 1830s and originally described by Riley and Stutchbury as three separate taxa: Thecodontosaurus antiquus based on a right dentary with 21 teeth, Paleosaurus cylindricon (Now Paleosauriscus cylindicon) and P. platyodon (now Rileyasuchus platyodon), the latter two, each based on a single tooth. The other bones were subsequently distributed by Owen (1842), Huxley (1870) and Marsh (1892) among the three taxa. Huxley (1870) was the first to recognize the dinosaurian nature of the remains. The different disarticulated bits had subsequently quite diverging and complicated systematic histories, some being referred to a phytosaur (i.e. Rileya), others to theropods and ornithosuchians. Sadly, a portion of the materials, including the holotype dentary of Thecodontosaurus, was destroyed during the WWII bombing of Bristol. Recent efforts try to put order in the systematic mess accumulated over more than a century, but opinions went from attributing all the Durdham Down dinosaurian bones to the single species of basal sauropodomorph, Thecodontosaurus antiquus (Benton et al., 2000) with different morphotypes representing sexual dimorphism, to reserving the generic name to the original jaw and its neotype only (Galton, 2005). In his last magisterial review, Pete Galton (2007) examined all the surviving materials of Durdham Down (including the mislabeled bones which were for a while thought to come from Australia, leading Seeley to described them in 1861 as a new species, Agrosaurus macgillivray, which would have been the earliest known dino from down under) and illustrations made of materials lost during the war. He concluded that the Durdham Down collection is a mixture originating from a handful of species: Thecodontosaurus antiquus, to which the jaw and gracile bones were attributed, a new erected taxon, Asylosaurus yalensis for the only significant articulated skeletal part (an almost complete forearm and associated dorsal vertebrae and ribs), and a few number of unnamed basal sauropodomorphs, including a possible anchisaur. New materials of Thecodontosaurus have been discovered in fissure fill at Tytherington Quarry, Avon, in 1975 are are being prepared and awaiting formal description. Compared to the later huge sauropods, Thecodontosaurus was a rather small dinosaur measuring no longer than 2.5 meters in length that was probably bipedal. His leaf shaped teeth indicated that it was a herbivore.

Fig 2.- Pantydraco caducus.

From the more or less contemporary fissures fill of Panty-ffynnon Quarry in South-Western Wales, came several partial skeletons including an almost complete skull and associated partial skeleton of the unfortunately named Pantydraco caducus. The remains are from a juvenile basal sauropodomorph. Like Thecodontosaurus, Pantydraco was a bipedal herbivore, measuring probably no more than 2 meters in length.

Fig 3.- Camelotia borealis.

The large Late Triassic sauropodomorph, Camelotia

All the sauropodomorphs from the rhaetian fissure fills were rather small in size and gracile in appearance, but a larger animal announcing the heavy sauropods from the Jurassic, existed at that time, as proven by a partial disarticulated skeleton found in sedimentary beds at the base of the Westbury formation at Wedmore Hill, Somerset. The animal was named Camelotia borealis, after the legendary castle of King Arthur.  Remains of Camelotia are so fragmentary that it is hard to derive its affinities but it might have been related to the quadrupedal Melanosaurus, unless it was a very primitive sauropod. Camelotia is estimated to have measured about 10 meters in length.

Original artworks on Paleoexhibit are copyrighted to Nobu Tamura. Do not use without permission (Email: nobu dot tamura at yahoo dot com)

References:

Benton M.J. , Juul, L., Storrs, G.W. & Galton, P. M. 2000. Anatomy and systematics of the prosauropod dinosaur Thecodontosaurus antiquus from the Upper Triassic of Southwest England. Journal of Vertebrate Paleontology 20: 77–108.

Fraser, N. C., K. Padian, G. M. Walkden, & A.L.M. Davis , 2002. Basal dinosauriform remains from Britain and the diagnosis of the Dinosauria. Palaeontology , 45 (1): 79-95.

Galton. P. M. 2005. Basal sauropodomorph dinosaur taxa Thecodontosaurus Riley & Stutchbury, 1836, T. antiquus Morris, 1843 and T. caducus Yates, 2003: their status re: humeral morphs from the 1834 fissure fill (Upper Triassic) in Clifton, Bristol, UK. Journal of Vertebrate Paleontology 25(3, suppl.):61A

Galton, P. M. 2007. Notes on the remains of archosaurian reptiles, mostly basal sauropodomorph dinosaurs, from the 1834 fissure fill (Rhaetian, Upper Triassic) at Clifton in Bristol, southwest England. Revue de Paléobiologie 26(2):505-591.

Galton, P. M., Yates, A. M.  and Kermack, D. M. 2007. Pantydraco n. gen. for Thecodontosaurus caducus Yates, 2003, a basal sauropodomorph dinosaur from the Upper Triassic or Lower Jurassic of South Wales, UK. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 243(1):119-125.

Naish, D. and Martill., D. M. 2007. Dinosaurs of Great Britain and the role of the Geological Society of London in their discovery: basal Dinosauria and Saurischia. Journal of the Geological Society, London 164:493-510

Yates. A.M. 2003. A new species of the primitive dinosaur Thecodontosaurus (Saurischia: Sauropodomorpha) and its implications for the systematics of early dinosaurs. Journal of Systematic Palaeontology 1(1):1-42.

R.I.P. Dan Varner (April 19, 1949 - January 1, 2012)

Mosasaurus by Dan Varner.

I did not have the privilege to know Dan Varner and did not know until very recently, shame on me, that he was the man behind the beautiful paintings illustrating the “Oceans of Kansas” website. I sadly learned that he passed away on January 1st, 2012 after a prolonged battle with illness;  a tremendous loss for the entire paleoart community…

From all the amazing Mesozoic marine life depictions he created during his too short a career, this one is a personal favorite. Mosasaurs were after all closely related to the modern monitor lizards, so it makes perfect sense to give them a similar tongue! The underwater light effect is eye-catching and the three transfixed ammonites watching the marine lizard swimming by gives to the entire scene a unique sense of cephalopodian apprehension... simply beautiful!

It’s hardly my place, I think, for me, an amateur nobody, to give a fitting eulogy to such a great artist so I am simply directing you to the ‘in memoriam’ sections I came across on the web, starting with the “Oceans of Kansas” website, followed by tributes from paleo-illustrators Jaime Headden (check his Globidens), Matt van Roojien, David Maas and from the Art Evolved Crew.