Ornithocheirus
Name:
Ornithocheirus (Bird hand).
Phonetic: Or-nith-oh-kye-rus.
Named By: Harry Govier Seeley - 1869.
Synonyms: Tropeognathus, Possibly also
Palaeornis, Cimoliornis, Criorhynchus, Cretornis.
Classification: Chordata, Reptilia,
Pterosauria, Pterodactyloidea, Ornithocheiridae,
Ornithocheirinae.
Species: O. simus (type).
Total number of species is under dispute,
see text.
Type: Piscivore.
Size: Roughly about a 5 meter wingspan, but precise
details uncertain.
Known locations: England - Cambridge Greensand.
Brazil - Santana Formation.
Time period: Albian of the Cretaceous.
Fossil representation: Well over forty sets of
remains have been attributed to different individuals, although there
validity is under debate.
Remains
of Ornithocheirus indicate that it was a medium
sized pterosaur however
Ornithocheirus has still had its total size grossly
overestimated in
the popular media, with the most outlandish suggesting that it had a
wingspan of twelve metres.
The
crests of Ornithocheirus were quite different from
the majority of
other pterosaurs in that they were on the tips of its beak as opposed
to its head. These crests extended from both upper and lower jaws,
with the upper crest extending towards the nostrils. Each crest was
convex, giving them a semi-circular profile.
Ornithocheirus
is thought to have lived in coastal regions where it would fly over the
sea to look for fish. Ornithocheirus also had a
different beak
structure to other related species in that the beak narrowed towards
the tip. This may have been to reduce water resistance while skim
fishing over the surface of the water. There are also a smaller
number of teeth which point vertical rather than out, perhaps as an
adaptation to catching larger fish.
A Taxonomic Headache
Many
of the early discovered species of pterosaurs that hark back to the
nineteenth century ended up with more species names than was
necessary. Although most of these have since had their species
listings cleaned up so that most if not all of the unnecessary species
have been repositioned into the valid ones, Ornithocheirus
still
causes continuing debate amongst pterosaur researchers about which
species are valid and which are not.
The
problems begin with the first remains that were recovered from the
Cambridge Greensand, a deposit that was once a sea bed. Because of
this the remains, while numerous, were not only disarticulated and
scattered, they were also eroded as well. Examining fossils that
are not eroded is hard enough, and because no one knew for certain,
the safe option was taken and they were assigned to the Pterodactylus
genus, at the time of which was being treated as a wastebasket for
any uncertain remains.
Although
some of the remains had already been attributed to Pterodactylus
most
of the material was still unclassified, so Harry Govier Seeley
undertook the task of identifying the remains. Seeley created the
genus Ornithocheirus, meaning 'Bird hand' in
the belief that
pterosaurs were ancestral to birds. Although we now know that birds
evolved from small theropod dinosaurs, this belief was quite common
during the nineteenth century. Although no type species was set,
Seeley did designate twenty-eight different species of Ornithocheirus
from the available remains.
When
these species were published in 1870, Richard Owen, by far the
most famous palaeontologist of the day in Britain, immediately
disputed the genus and species designation. This was on the grounds
that he did not consider Ornithocheirus ancestral
to birds, in fact
Richard Owen did not even believe in evolution, and as such the
'bird' part of the name was not justified. This was not the only
time that Owen would try to rename a species because it did not fit the
name, he also tried to have the prehistoric whale Basilosaurus
renamed because the 'saurus' part meant lizard when obviously
whales are mammals. Owen created two new genera, Coloborhynchus
and
Criorhynchus, of which only Coloborhynchus
continues to be recognised
to this day. Seeley however rejected Owen's renaming and designated
the type species as well as adding another.
After
this other researchers undertook the mantle of sorting out
Ornithocheirus, although the number of species
would rise to well
over forty. In 1914, Reginald Walter Hooley tried to restructure
the growing number of Ornithocheirus species. He
did this on the
basis of jaw shapes and in so doing he created the genera Amblydectes
(blunt biter) and Lonchodectes
(lance
biter). However
Amblydectes has since become a synonym of Coloborhynchus.
Brazilian
pterosaur discoveries towards the end of the twentieth century revealed
exceptionally well preserved specimens that almost immediately drew
comparison to pterosaurs like Ornithocheirus and Coloborhynchus.
However although many European researchers find the Brazilian
pterosaurs to be similar, Brazilian researchers have disputed the
addition of these remains to the European genera.
On
top of all this the majority of pterosaur researchers acknowledge the
fact that the original Cambridge Greensand specimens are so poorly
preserved that it's impossible to assign anything to them with a strong
degree of certainty. So, unless a much better preserved specimen of
Ornithocheirus can be recovered, ideally from
Western Europe so that
it can be more easily attributed to the Cambridge Greensand material,
the current species of Ornithocheirus including
the type specimen
named after only a partial jaw may continue to have question marks
hanging over them.
Further reading
- Index to the Fossil Remains of Aves, Ornithosauria, and Reptilia,
from the Secondary System of Strata, Arranged in the Woodwardian Museum
of the University of Cambridge. - Annals and Magazine of Natural
History. 5 (27): 225–226. - H. G. Seeley - 1869.
- On the Ornithosaurian genus Ornithocheirus, with a review of the
specimens from the Cambridge Greensand in the Sedgwick Museum,
Cambridge. - Annals and Magazine of Natural History. 13 (78): 529–557.
- Reginald Walter Hooley - 1914.
- Taxonomic review of the Ornithocheirus complex
(Pterosauria) from the
Cretaceous of England. - ZooKeys (308): 1–112. - T. Rodrigues &
A. Kellner - 2013.
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