Tusoteuthis
Name:
Tusoteuthis.
Phonetic: Too-so-te-ew-fiss.
Named By: Logan - 1898.
Classification: Mollusca, Cephalopoda,
Cephalopoda, Coleoidea, Vampyromorphida?
Species: T. longa (type).
Diet: Carnivore.
Size: Estimates vary and range from about 6 to
11 meters long (based upon giant squid and if measured from the
mantle to the tips of the tentacles).
Known locations: Canada, Manitoba - Pierre
Shale Formation.
Time period: Campanian of the Cretaceous.
Fossil representation: Several specimens of the
gladius (shell inside of the mantle).
Tusoteuthis
is a surprisingly little known Mesozoic animal, even though it is
potentially one of the largest squids to ever swim in the ocean.
Unfortunately the only preserved remains of Tusoteuthis
currently
known are of the gladius (sometimes called a ‘pen’). The
gladius is essentially an internal shell that is a feature also seen in
modern day squid genera that we can see swimming in the oceans.
Early
comparisons of the gladius of Tusoteuthis saw it
being compared to the
gladius of Architeuthis, more popularly known as
the giant squid.
From this Tusoteuthis was estimated to have had a
comparable mantle
(main body) length to Architeuthis. Adding on
the head, the arms
and the feeding tentacles at full extension, the total length of
Tusoteuthis was estimated at around eleven meters,
a bit shorter than
a very large specimen of the giant squid that we know today, and
also smaller than Mesonychoteuthis, better known
as the colossal
squid.
However
the interpretation of Tusoteuthis as being similar
to Architeuthis has
now been questioned with comparisons to Vampyroteuthis
(better known
as the vampire squid) now appearing. This is because the gladius of
Tusoteuthis is actually more like the gladius of Vampyroteuthis
in its
form. If this is correct, and if Tusoteuthis
had similar body
proportions to Vampyroteuthis, then it certainly
would not have been
eleven meters long, but possibly around six meters with a much
stockier body than Architeuthis.
Unfortunately
without soft tissue preservation, even in the form of a rock
impression, we will never know what the exact body proportions of
Tusoteuthis were, all we can do is make a best
guess. Given the
presumed size of the animal such preservation is extremely unlikely
unless a smaller juvenile was somehow preserved. Hope should not be
lost however as the soft tissues of other cephalopod genera such as
Proteroctopus,
Vampyronassa
and Palaeoctopus
are known to us,
though these specimens are of small individuals. There small size
means that less sediment was required to bury and preserve them.
As
a large cephalopod, Tusoteuthis is expected to
have been a powerful
hunter of animals including such things as fish and even other
cephalopods. Also given the much higher abundance of marine reptiles
during the late Cretaceous, it is perhaps possible that Tusoteuthis
may have hunted and attacked smaller marine reptiles when given the
opportunity. However there is strong fossil evidence that proves that
Tusoteuthis were themselves attacked and eaten by
other animals such as
mosasaurs
and large fish. There is even one specimen of a Tusoteuthis
that was being swallowed by a Cimolichthys
nepaholica, a type of fish
related to salmon. This fish seems to have attacked a squid too large
to swallow however as the gladius of the squid was found within the
throat of the fish not the stomach. It's probable that the squid
became stuck while being swallowed mantle first, blocking off the
gills so that the fish basically suffocated.
Further reading
- Statigraphic and taxonomic significance of Tusoteuthis
longa Logan
(Coleoida, Teuthida) from the Pembina Member, Pierre Shale
(Campanian), of Manitoba. Journal of Palaeontology, 61 (4)
727-737 - E. L. Nicholls & H. Isaak - 1987.
- Cretaceous fish predation on a large squid. - Evolutionary
Paleobiology of Behaviour and Coevolution, 195-197. - E. G.
Kaufman - 1990.
- Examples of vertebrate predation on cephalopods in the late
Cretaceous of the Western Interior. - Evolutionary Paleobiology of
Behaviour and Coevolution, 203-207. - J. D. Stewart
& K. Carpenter - 1990.
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