Streptospondylus
Name:
Streptospondylus
(Reversed vertebra).
Phonetic: Strep-toe-spon-dy-luss.
Named By: Christian Erich Hermann von Meyer -
1832.
Synonyms: Laelaps gallicus, Megalosaurus
cuvieri?
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda.
Species: S. altdorfensis
(type).
Diet: Carnivore.
Size: Uncertain, but roughly estimated to be up
to 7 meters long.
Known locations: France, Lower Normandy.
Time period: Upper Callovian/Early Oxfordian of the
Jurassic.
Fossil representation: Vertebrae and partial limbs
and partial left pubis.
Streptospondylus
could have become the first dinosaur to be scientifically recognised.
Starting in 1770 vertebrae and limb remains were steadily
recovered and over the course of the following years many fossils for
separate locations were collected before being sent to the Museum
National d'Histoire Naturelle in Paris, France in 1800. These
fossils were then added to collections from further areas by one
Georges Cuvier. In 1808 Georges Cuvier, one of the pioneers of
comparative anatomy as well as one of leading naturalists of his time
finally put forward a scientific description of the bones. However
the concept of large reptilian creatures like dinosaurs was still many
years away and so when Cuvier described a vertebra that we now know
belonged to a theropod dinosaur, he believed that what he was dealing
with were the remains of crocodiles.
Building
upon the work of Henry De La beche, Cuvier realised in 1822 that
the fossils he had previously described were actually from differing
time periods. Cuvier did not specify names for these fossils, but
in 1824 he outlined that there were two types. Also in 1824,
the first creature that would later be known as a definitive dinosaur
was named Megalosaurus
and as such this is why Megalosaurus is down in
history as the first dinosaur genus to be named and described.
However the actual term dinosaur would still not be coined for another
eighteen years. In 1825 another naturalist named Etienne Geoffroy
Saint-Hilaire created a new genus of crocodile called Steneosaurus
based upon two skulls. This new genus included the theropod dinosaur
vertebrae, though it was still not realised what this was.
Eventually
in 1932 the German palaeontologist Christian Erich Hermann von
Meyer was studying Steneosaurus fossils and
identifying several fossils
that should have belonged to other genera, including the marine
crocodile Metriorhynchus.
von Meyer also found the theropod
vertebrae, and since this was many years after the much publicised
discovery of the first dinosaur genera, specifically Megalosaurus,
von Meyer was quick to realise what it was. That year von Meyer
established Streptospondylus altdorfensis as a new
genus.
In
1842 the British naturalist Richard Owen (who in the same year
established the dinosaurs as a group for the first time) took issue
with the type species name of Streptospondylus.
Because
Streptospondylus altdorfensis was based upon fossils
once attributed to
Steneosaurus rostrominor, Owen believed that the
type species should
be written as Streptospondylus rostromajor since it
was based from the
earlier species, and when establishing this he assigned an
attributed skull as holotype. Owen was also responsible for greatly
increasing the number of Streptospondylus species from this time,
creating S. major in 1842, S.
recentor and S. meyeri in
1851 and S. Grandis in 1854. All four of
these species are
today considered to have been based upon fossils of Iguanodon,
the
second dinosaur genus named, as well as an ornithischian dinosaur
that is considerably different to theropods which are saurischian
dinosaurs.
Owen
also named one more species in 1842 however. S.
cuvieri was
described from a single damaged vertebra. In 1861 Owen assigned
the original material described by Cuvier to S. cuvieri
even though
S. rostromajor would technically have priority
because it was named
first. In 1923 a braincase of a theropod was also assigned to S.
cuvieri by Jean Piveteau on the basis that it was recovered
from the
same approximate area as the earlier fossils.
Things
began to change in 1964 when the palaeontologist Alick Walker
renamed Streptospondylus cuvieri as a new species
of
Eustreptospondylus,
E. divesensis, the braincase serving as the
holotype. Later in 1977 two other palaeontologists named P.
Taquet and S. P. Welles used the braincase to establish a new
theropod genus, Piveteausaurus.
In 2001 Ronan Allain stated
that there is no connection between the braincase and the older
theropod fossils that were included with it and that only the braincase
could be used to indicate Piveteausaurus as a
genus. Allain also
proved that the skull which was designated the holotype for
Streptospondylus rostromajor by Owen in 1842 was
in fact a
composite fossil of more than one creature. With the holotype for S.
rostromajor disproven as valid, the older name of S.
altdorfensis
was resurrected as the type species of Streptospondylus.
Today only
the definitely theropod fossils of the original assignments are
considered the valid fossils, and S. cuvieri
reduced to very little
distinctive material is now widely regarded as a Nomen dubium.
With
so little fossil material known for this genus not much is known about
this dinosaur. As a theropod it would have been a bipedal dinosaur
and probably a predator of other dinosaurs. The full size of
Streptospondylus cannot be definitely established,
but it has been
estimated to be around seven meters long, based upon comparisons to
more complete theropod genera. Another theropod genus named
Magnosaurus
is popularly believed to have been a close relative of
Streptospondylus. In fact Gregory S. Paul
informally named
Magnosaurus as a species of Streptospondylus,
S. nethercombensis,
in 2010, though to date Magnosaurus is still
regarded as a valid
genus by most palaeontologists.
Further reading
- A quantity of bones found in the rocks in the environs of
Honfleur, by the late Abb� Bachelet, G. Cuvier - 1800.
- Sur les ossements fossiles de crocodiles et particuli�rement sur
ceux des environs du Havre et d'Honfleur, avec des remarques sur les
squelettes de sauriens de la Thuringe, G. Cuvier - 1808.
- Recherches sur l'organisation des gavials, E. Geoffroy
Saint-Hilaire - 1825.
- Report on British fossil reptiles, Richard Owen - 1842.
- Triassic reptiles from the Elgin area: Ornithosuchus
and the
origin of carnosarus, A. D. Walker - 1964.
- Redescription du cr�ne de dinosaure th�ropode de Dives
(Normandie) [Redescription of a theropod dinosaur skull from Dives
(Normandy)], P. Taquet & S. P. Welles - 1977.
- Redescription de Streptospondylus altdorfensis,
le dinosaure
th�ropode de Cuvier, du Jurassique de Normandie [Redescription of
Streptospondylus altdorfensis, Cuvier's theropod
dinosaur from the
Jurassic of Normandy], R. Allain - 2001.
----------------------------------------------------------------------------
Random favourites
 |
 |
 |
 |