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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