Pelorosaurus
Name:
Pelorosaurus
(Monstrous lizard).
Phonetic: Pel-o-ro-sore-us.
Named By: Gideon Mantell - 1850.
Synonyms: Cetiosaurus conybeari.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Sauropoda, Brachiosauridae.
Species: P. conybeari
(type).
Diet: Herbivore.
Size: Estimated about 16 meters long.
Known locations: England - Lower Greensand
Group, Wealden Group, and France.
Time period: Mid Tithonian to end of the early
Cretaceous.
Fossil representation: Various partial post cranial
remains.
The
first sauropod
dinosaur to ever be named was Cetiosaurus,
which was
named in 1841 by Richard Owen. Owen however did not realise that
he was dealing with a dinosaur, he actually thought that he was
dealing with a giant marine crocodile. The first sauropod to actually
be identified as a dinosaur was actually Pelorosaurus,
named in
1850 by Gideon Mantell, the man who named Iguanodon,
the first
plant eating dinosaur to be named, and second dinosaur overall (it
was narrowly beaten by Megalosaurus).
Understanding
the taxonomic history of Pelorosaurus from this
point can give you a
headache, but in simple facts its goes like this. After Cetiosaurus
was first named Owen named many species because of differences in
attributed remains, but it was later realised that some of these
fossils were from different animals, and not attributable to
Cetiosaurus. One species, Cetiosaurus
brevis was realised to have a
mix of sauropod and iguanodont bones by Alexander Melville, who
subsequently took the sauropod material to create a new species of
Cetiosaurus, C. conybeari,
in 1849. The ‘conybeari’ part
was in honour of William Conybeare, a geologist who published the
first ever description of a plesiosaur, creating the genus
Plesiosaurus
in 1821.
Then
in 1950 Gideon Mantell took the sauropod fossils of C.
conybeari
and realising them to be different from the others of the genus used
them to establish a new genus. Adding a humerus that was confirmed to
come from the original fossil site, Mantell knew that he was dealing
with a big animal, and at first considered Colossosaurus, initially
thinking that the Ancient Greek ‘kolossos’ meant giant, though
when he checked he realised that it actually meant ‘statue’ (to be
fair to Mantell, the most famous colossuses are generally very
large). Mantell instead went with Pelorosaurus
which means
‘monstrous lizard’ while the species name was kept as conybeari in
keeping with naming guidelines concerning the naming of animals.
This
would have been a simple case of naming a new genus from an established
species, something that is standard fare in naming animals. However
Richard Owen perceived the species and genus re-namings by Melville and
Mantell as attacks upon his credibility as a naturalist. Owen after
all held important positions in the fields of British natural history,
and would have course wanted to protect his authority to hold those
positions. Owen was also quick to try and alter the works of others,
including renaming already established genera (Basilosaurus
and
Ornithocheirus
to name but two). Some may note that Owen only
sought to be scientifically clear, but less kind critics might call
them deliberate attempts to stamp his name upon important discoveries.
Richard
Owen’s counter to the creation of Pelorosaurus
was to immediately
discredit the work of Melville and Mantell. He accused Mantell of not
understanding the meaning of the name ‘brevis’, as well as
claiming that his original 1842 description of the name was
intended as a basic description. Owen conceded that C. brevis was
likely a nomen nudum, but saw to fix this by assigning further
sauropod fossils. When dealing with the creation of the genus
Pelorosaurus, Owen removed all fossil material
with the exception of
the humerus that was added by Mantell. Then later in 1859, Owen
once again attributed iguanodontid vertebrae to Cetiosaurus
brevis.
Stating that any connection of Pelorosaurus to Cetiosaurus
was a
mistake, and satisfied that his Cetioasurus brevis
had been
preserved, this was last that anything was said about it for just
over a hundred years.
While
Owen was a leading figure in the early years of dinosaur
palaeontology, much of his work has not stood the test of time. A
1970 study by John Ostrom and Rodney Steel applied modern reasoning
to Owen’s attempts at preserving Cetiosaurus brevis.
Their
conclusions were that Owen had simply tried to replace the holotype of
Cetiosaurus brevis, something that should not have
been allowed,
and certainly could not be accepted today. Criticism was also made
of Melville’s decision to remove the sauropod fossils and not the
iguanodont fossils, which really should have been removed instead.
The
result is that even though Pelorosaurus is only
represented by a few
fossils, it has actually been seen as valid since the late Twentieth
century, with Cetiosaurus conybeari named as a
synonym to the genus.
A second species of Pelorsaurus, P.
becklesi which was named from
partial remains and skin impressions is no longer thought to represent
Pelorosaurus, but rather a different titanosaur
genus. Various
fossils from England and now also France have been assigned to
Pelorosaurus, though often as indeterminate beyond
a genus level.
Pelorosaurus
is usually considered to be ranged from the very end of the Jurassic to
possibly as the end of the early Cretaceous, though most remains seem
to be earlier in the early Cretaceous. The isolated nature of many
Pelorosaurus fossils has led to confusion about
this. Overall
Pelorosaurus is perceived to have been a
brachiosaurid sauropod,
approximately some sixteen meters in length. Pelorosaurus
may have
coexisted with other sauropods such as Xenoposeidon.
Further reading
- Report on British fossil reptiles, Part II. - Reports of the
British Association for the Advancement of Science, 11: 60-204.
- Richard Owen - 1842.
- Notes on the vertebral column of Iguanodon. - Philosophical
Transactions of the Royal Society of London, 139: 285-300. -
A. G. Melville - 1849.
- On the Pelorosaurus: an undescribed gigantic
terrestrial
reptile, whose remains are associated with those of the Iguanodon
and
other saurians in the strata of Tilgate Forest, in Sussex. -
Philosophical Transactions of the Royal Society of London, 140:
379-390. - G. A. Mantelli - 1850.
- Monograph on the fossil Reptilia of the Wealden and Purbeck
formations. - Palaeontological Society, London. - R. Owen
- 1853.
- Monograph on the fossil Reptilia of the Wealden and Purbeck
formations. Supplement no. II. Crocodilia (Streptospondylus,
etc.). [Wealden.] - The Palaeontographical Society, London
1857: 20-44. - R. Owen - 1859.
- Saurischia. Handbuch der Pal�oherpetologie/Encyclopedia of
Paleoherpetology. - Gustav Fischer Verlag, Stuttgart 1-87. -
R. Steel - 1970.
- An unusual new neosauropod dinosaur from the Lower Cretaceous
Hastings Beds Group of East Sussex, England. - Palaeontology,
50(6): 1547-1564. - M. P. Taylor, D. Naish -
2007.
- Sauropod dinosaurs. In Batten, D. J. (ed.) English
Wealden Fossils. The Palaeontological Association (London),
pp. 476–525. - P. Upchurch, P. D. Mannion &
P. M. Barrett - 2011.
----------------------------------------------------------------------------
Random favourites
 |
 |
 |
 |