and Mesonychoteuthis, the giant and colossal
squid, are enigmatic and awe inspiring animals. Very little is known about the
lifestyle of these spectacular animals, despite the examination of numerous
corpses of Architeuthis, much of what we know about the animals'
behaviour and lifestyle boils down to educated speculation. What is not so well
known is that these modern squid were not the first giant squid in the Earths oceans, we have tantalising remains of animals that were at
least as large as these modern species that shared the oceans with the
ammonites, mosasaurs, giant turtles and plesiosaurs
about 80 million years ago during the Late Cretaceous period. Imagine the
difficulties of reconstructing these ancient animals when all we have to go on
are fragmentary fossilised remains of the pens, or gladius,
of these animals!
The teuthid gladius is the internal remnant of the exterior shell of the
primitive nautiloid ancestral cephalopods. The gladius is contained within a "shell sac" to which the
muscles are attached, the gladius providing
strengthening and support for the mantle, the main body of the squid. "Fossil Teuthids"
are largely identified and classified by variations in the shape of the gladius alone and comparisons with living species of cephalopods; soft bodied
parts, in those rare cases of exceptional preservation, are not generally
diagnostic or much use in determining species interrelationships. Unfortunately
the gladius alone does not help us to understand how
these animals appeared and behaved in much detail; one only has to think of the
wide variety of body shapes, visual displays, variations in habitat and
behavioural differences in living cephalopods to imagine how much we have lost and will never be able to
reconstruct with these ancient animals.
Upper Cretaceous "teuthid"
remains are very poorly known from North America; as an example the trachyteuthid Actinosepia
canadensis is the most common specimen and this
is known from just 25 examples (1987 figure). Prehistoric giant squid remains
are known purely from the shallow Western Interior Seaway, which was a vast sea
that bisected North America, so vast that at times it connected the Gulf of Mexico to the Arctic covering the great
American Plains of today. These seas arose during the Early Cretaceous following a period of rapid
global warming, sea floor spreading and rise. This seaway is thought to
have been very shallow, generally less than 600 feet deep, with a flat muddy
bottom. The seaway was biologically
extremely active and squid were seemingly common animals, five species have
been described, the large squids Kansasteuthis
lindneri and Enchoteuthis
melanae but the largest of all were Niobrarateuthis
bonneri, Niobrarateuthis walkeri
and Tusoteuthis longa.
Each of these species was described on the basis of a single specimen. All
these animals are known from remains of the gladius
alone, the stiffening rod running the length of the mantle, the different
species were known from variations in the size and form of this cuttlebone
until recent revisions grouped all these animals together under one genus.
These four genera of squid were roughly
contemporary; "teuthid" remains have been found in
the vast 85-80 million year old Niobrara chalk deposits
that stretch from south-west Kansas to Manitoba in Canada. Niobrarateuthis is chiefly known from the Upper Niobrara chalk formations in Logan County at the
Smoky Hills in Kansas. Fossils have also been identified in the Pembina
member of the Pierre Shale that lies immediately above the chalk at a date of
79 million years old. Tusoteuthis remains have
now been identified from these Pierre Shale deposits in Kansas, North and South Dakota and
from six specimens from southern Manitoba in Canada. All are from deposits at the Eastern margin of the Western Interior Basin.
To date two species of Niobrarateuthis
have been identified, N. bonneri and N. walkeri. N. bonneri was described by H.W. Miller in 1957 on the
basis of three specimens found in the late thirties in the Niobrara
Chalk at the Smoky Hills, and N. walkeri in 1977 by R.G.
Green on the basis of one very badly crushed specimen. Miller regarded Niobrarateuthis
distinct from Tusoteuthis longa in that Tusoteuthis
had a lance-shaped gladius and lacked a prominent
keel. However, it may be misleading to identify these large squid as separate
animals; a 1987 paper by Nicholls and Isaak (1987) has
suggested that all five teuthid species from the
Western Interior Sea can in fact be regarded as one species, Tusoteuthis longa. The
differences in morphology noted above could be explained as artifacts of
preservation, deformations caused by crushing during the process of
fossilization and misinterpretation of dorsal and ventral surfaces. The sole
specimen of the gladius of Niobrarateuthis
walkeri was considered by Nicholls and Isaak to be so badly broken and crushed that any attempt at
reconstruction would be largely hypothetical. This theory has now achieved
general acceptance; all recorded examples of Niobrarateuthis,
Kansasteuthis and Enchoteuthis
are now in fact regarded as one and the same genus, Tusoteuthis
longa. The name Tusoteuthis
has been adopted as the common name as it was the earliest name used (Logan 1898) and took precedence
over the others.
Giant prehistoric squid are also known from other parts of the world. At Richmond, in Queensland, Australia a 100
million year old 1.3 metre gladius
was discovered by
14 year old Sonia Ievers
, and has been christened Boreopeltis soniae
in her honour. This is currently on display at the Richmond Marine Fossil Museum. Students
in Queensland located a contemporary second gladius in 1998 that measured over a meter in
length and possibly shows evidence of predation by Kronosaurus
a large pliosaur
Smaller related species of Boreopeltis
are known from the Mid Cretaceous (Aptian
black shale deposits, Heligoland
is a small island 50 km off the north German
coast and has a 1m thick shale deposit that has preserved a number of fossil teuthid
forms in exceptional detail, other genera found
there include Mastigophora
The whole working system of fossil "teuthid" taxonomy is still being compiled. The evolutionary
history of the orders of squid and other non-belemnoid
coleoid cephalopods is very poorly understood chiefly due to the lack of fossils
of these creatures; normally the only part of the animal that tends to become
fossilised is the chitinous gladius,
or pen, and even that is very rarely preserved due to its delicate nature. Much
of what is currently understood about evolutionary relationships of these
animals has not been agreed upon; there are two or three differing models of
the coleoid tree, each new discovery may call for the
models to be reworked. The only really well preserved coleoid
faunas are at localities such the 150 million year old Late Jurassic German Solnhofen and Holzmaden deposits
and the 100 million year old Cretaceous Hajoula
deposits from Lebanon, and a handful of other lesser known localities. These represent
snapshots of biodiversity; what happened in between them is tantamount to
educated guesswork with rare and isolated specimens providing evolutionary
clues. Most collections in museums are labelled simply as "Fossil Teuthids".
Nonetheless, a little of the
evolutionary history has been determined, even if it is somewhat speculative.
It is currently thought that these ancient giant squid were members of the vampyromorpha based on similarities in the shape and
structure of the gladius to the only extant member, Vampyroteuthis, the Vampire Squid. This is in common
with many of the Jurassic "teuthids" from Germany
and the Cretaceous animals from Lebanon.
Tusoteuthis is believed to be only very distantly
related to Architeuthis, and was originally assigned by Adolf
Naef to a completely separate branch of the family
tree, the Family Palaeololiginidae, of the Suborder Mesoteuthina,
a vampyromorph group that failed to survive the mass
extinction at the end of the Cretaceous. These Palaeololiginidae are well
documented in Germany from the Late Jurassic lithographic limestones.
Adolf Naef identified this
group in 1921 but he later admitted that he had not examined the actual gladius fossils themselves when assigning Tusoteuthis to the Paleololiginidae
and was working from a description; Nichols and Isaac revised the family to the
Kelaenidae in 1987. (Miller had also assigned Niobrarateuthis
to the Kalaenidae in 1968)
The taxonomy of Tusoteuthis can now be provisionally placed as
(Disclaimer: not all
researchers would accept this alignment, some place the Mesoteuthina
with the Teuthida, and a different family tree
Architeuthis & appearance
According to Theo Engeser's
model of coleoid evolution, the latest common
ancestor of Architeuthis and these Mesoteuthina
lived in the Devonian period, possibly over 380 million years ago. As these
giants are not believed to be ancestral to Architeuthis and left no
post-Cretaceous descendants, it appears that giants have evolved at least four
times in separate families, probably once in the MidCretaceous (Boreopeltis from Australia), once in the Late
Cretaceous (Tusoteuthis) and twice at a fairly
recent date (Architeuthis and Mesonychoteuthis).
The complete lack of fossils of Architeuthis' immediate ancestors makes
it impossible to determine when the recent giants arose. The difference between
Architeuthis, Tusoteuthis and Niobrarateuthis
can be seen when the gladius of the three animals is
compared, Architeuthis' gladius is a long
slender feather-shape; that of Tusoteuthis is
more robust, with a broader, humped and leaf-shaped conus,
gladius resembles that of a sturdy rounded paddle.
However, as mentioned above, it is now generally accepted that differences in
the shape of the gladius of the ancient giants may
simply be an artifact of preservation and the animals
may, in fact be one and the same. The radically different shape of the gladius of Architeuthis may indicate that these
Western Interior Seaway squid had a differing external appearance in the shape
of the mantle, perhaps broader at posterior end of the animal.
The external appearance of these ancient
giants can really only be a matter of conjecture, we have no trace of tentacles
or arms with these animals; all we can really say is that it is probable that
the mantle was probably of a similar length to a fully grown Architeuthis
as the largest fossilised gladius is of a similar
length to the modern giant. The longest rhacis of the
six Manitoba specimens measures at just over 1.2m in length but the sixth and
most recently recovered specimen is larger but incomplete, and would have
belonged to an animal which was a third larger again; it is unknown what the
maximum size adult animal would have been. If one assumes a consistent growth
rate maintaining the same proportions and ratios, then this sixth gladius would have been approximately in the order of 1.8m
if complete, and there is no evidence to suggest that this was fully grown. At
the time of writing (May 2004), another gladius
measuring six foot (1.8m) is being prepared for display at the North Dakota
Heritage Centre at Bismark, this was a find from the Pierre Shale at Pembina Gorge and is probably another Tusoteuthis,
(unconfirmed at time of writing). The maximum length of an Architeuthis gladius can be taken to be 2.15m (one specimen had a mantle
length of 2.25m and the gladius almost runs the
length of the mantle) so it appears that the mantle of Tusoteuthis
was of comparable size, if a little shorter. With so few specimens to work from
we cannot be sure what was the maximum size attained by Tusoteuthis,
a future gladius discovery may yet equal or exceed Architeuthis
It seems likely that these ancient animals
had eight arms and no tentacles, as there is no evidence that any of the other vampyromorphs, such as Plesioteuthis
or Trachyteuthis, had ten arms.
Observations of ten armed fossil species have recently been reinterpreted as
misinterpretation of drag marks in the silt (Fuchs, Keupp
and Engeser 2003). Given that it is almost certain
that these giants did not have these seizing tentacles of Architeuthis,
it is likely that these animals had a Total Length (tip of tentacles to tip of
mantle) shorter than Architeuthis, but the Standard Length (tip of arms
to tip of mantle) may have been of a similar size. We may be looking at an
adult Tusoteuthis with a Total Length of five
or six meters; this is assuming, of course, that Tusoteuthis
did not have exceptionally long arms! It is difficult to determine if they
would have had ink sacs but it is certainly possible as many other earlier
German Jurassic vampyromorphs have this feature. Arm
hooks are likely, but suckers do not fossilise and their presence cannot be
Another difference between Architeuthis
and the ancient giants is that of lifestyle as they lived in very different
environments. Architeuthis is thought to frequent depths of 600-1000 feet,
whereas the maximum depth of the Western Interior Seaway was just 600 feet. It seems logical to assume that the eyes of Tusoteuthis were probably of a lesser diameter than Architeuthis
as it lived in shallower conditions with more available light. There is some
indirect evidence that these ancient squid may have even lived close to the surface, as
detailed below a specimen of a Tusoteuthis gladius has been discovered with bite damage, this is
likely to have been caused by a mosasaur, an
important marine predator in the Seaway, and not likely to have been a deep
Evidence of Predation
Tusoteuthis probably would have constituted a major dietary
component for fish and marine reptiles throughout the Western Interior Seaway.
The evidence for this comes from coprolites (fossilised faeces), damaged gladius fragments and a choked fish!
A total of five
specimens of coprolites have been collected from separate locations (1987
figure). Two of these coprolites were collected from a Niobrara chalk exposure in Rooks County, Kansas and contain three broken fragments of gladius
between them. Three more coprolites
containing small Tusoteuthis inclusions were
obtained from the chalk at the junction with the Pierre Shale in Gove County, Kansas, one of which also contains fish teeth and vertebrae.
From the coprolites alone it is difficult to determine what animal was eating Tusoteuthis, but from the small size of these
coprolites researchers have concluded that this was probably some form of large
predatory fish (largest is 4.78cm x 3.82cm). Another specimen
from the chalk at Logan county consists of a mass of varied fish vertebrae,
jaws, skull fragments and teeth along with fragments of a large teuthid gladius, it is believed
that this is probably the stomach contents of a large carnivore of indeterminate
origin. This specimen measures 26.7cm x 16.5cm x 4.4cm is currently held at Fick Fossil Museum, Oakley, Kansas.
For two specimens of Tusoteuthis from the Pierre Shale at Red Bird, Wyoming, the predators are identifiable. A spectacular
discovery of a partial specimen of the predatory fish Cimolichthys nepabolica contained a nearly complete gladius of Tusoteuthis
that had been swallowed whole, and was so large it had probably choked the fish
to death. Cimolichthys was a large primitive teleost
probably related to the salmon and resembling a barracuda in form with conical
and widely spaced teeth suitable for puncturing flesh. It is believed to have
been an open water predator adapted for sustained swimming and rapid bursts of
speed and was a long-ranging and common species in the Western Interior Seaway.
This particular specimen of the fish is incomplete, the preserved section
measures 152cm in length but it contains a nearly complete 66cm gladius of an immature Tusoteuthis.
The squid is lodged in the area of the stomach of the fish with the
expanded rear of the gladius stuck in the ribcage in
the area of the shoulder of the fish. The rhacis or
'handle' of the gladius projects towards the mouth
where it appears to be broken below the left gill cover. It seems likely that Cimolichthys
approached the squid from the rear, attacked and attempted to swallow the
animal whole; the head and arms of the squid would have projected from the
mouth and it probably struggled, death for the fish probably came from the
fractured gladius ripping through the skin of the
squid and causing interior gill damage or the size of the body of the squid
forcing the gullet to remain open. This amazing specimen is currently held at
the University of Colorado Museum.
Mosasaurs are also believed to have been predators of Tusoteuthis and other cephalopods. Ammonites have been reported with mosasaur bite damage and fossils have also been found with teuthid hooks in their gut contents. A 128cm Tusoteuthis gladius also
housed at the University of Colorado Museum bears three punctures along the
length of the rhacis. These punctures forced the rod
bundles from which the rhacis is composed to splay
apart and cause some severe twisting to the structure. The punctures are widely
spaced, the distance of 31cm between two of the punctures has been interpreted
as an oblique angle of attack by the mosasaur. The
number of times the mosasaur bit the squid is
unknown, it is unclear if the struggling squid was released or the body was
severed allowing the gladius and mantle to sink to
the sea floor. This specimen was collected from the Sharon Springs Member of
the Pierre Shale, and it is thought that the predator was probably Tylosaurus proriger
known from the same deposits.
Potentially the largest fossil coleoid to be discovered to date was published in January 2006 by Kazaushiga Tanabe, Yoshinori Hikida and Yasuhiro Iba. It consisted of one half of an enormous set of jaws discovered in Late Cretaceous Campanian (83-71 mya) sediments at Wakkaweenbetsu Creek, Nakagawa Town, Hokkaido, Japan. The fossil was composed of a black phosphatic material and was contained inside a calcareous nodule. Included with the specimen were numerous bivalves and specimens of the heteromorphic ammonite Polyptychoceras
. The fossil came from the Upper Yezo Group of mudstones, 'Yezo' being an old name for Hokkaido. The fossil is an upper jaw that measures 97mm in length and is 22.5mm wide at its maximum point. It has a very sharply pointed rostrum that is angled acutely, and both the inner and outer lamellae are present.
In order to determine the systematic relationship of the specimen, the authors performed a cladistic analysis based on 5 morphological characteristics of the jaw in comparison with 22 other extant coleoids and Nautilus
. As a result of this and from a physical comparison of the shape of the rostrum and wings, the authors determined that the specimen is closest to the sub-order Oegopsina. The authors then attempted to estimate a total size for the animal, by examining the ratio of the maximum length of the upper jaw (LUJ) to total mantle length (ML) in eight extant coleoid species. Applying these derived ratios to the fossil jaw and plotting it along with these other specimens, it was concluded that the Mantle Length was probably akin to Architeuthis
. The jaw is similar to Architeuthis
not only in overall size, but in shape, and structure. It differs in that the crest margin is more convex in shape and has more prominent growth lines on the inner lamella.
The authors conclude that this specimen represents a large new species, Yezoteuthis giganteus
, that would have been present in Late Cretaceous Northwest Pacific along with many small ammonoid and nautiloid shelled cephalopods. The jaw is currently housed at the Nakagawa Museum of Natural History.
In summary, Tusoteuthis was probably a major component of the
ecosystem of the Western Interior Seaway and a favoured prey item of assorted
marine predators. It probably lived in shallow depths and would have been a
fast moving muscular squid as demonstrated by its robust gladius
providing anchorage for powerful musculature. Possibly as large as Architeuthis,
it would have thrived in a very different and extremely biologically active environment.
1) Morden District Museum, Manitoba, Canada. http://www.mordenmuseum.com/
2) North Dakota Heritage Centre at Bismarck (expected late 2004?). http://www.state.nd.us/hist/hcenter.htm
3) Natural History Museum of Los Angeles County, California as part of the "Savage Ancient Seas" Exhibit.
Sternberg Museum of Geology at the University of Kansas, Fort Hays, Kansas. http://www.oceansofkansas.com/Sternbrg.html
A painting and gladius can
be seen at the Australian Richmond marine fossil museum "Kronosaurus
ELLIS, R. Aquagenesis.
FUCHS, D., KEUPP, H., and
ENGESER, T., New records of soft parts of Muensterella
scutellaris Muenster, 1842 (Coleoida)
from the late Jurassic Plattenkalks of Eichstatt and their significance for Octobrachian
relationships. Berliner Palaobiol.Abh. 03: 101-111 Berlin 2003.
KAUFFMAN, E. G.,
Cretaceous fish predation on a large squid.
Evolutionary Paleobiology of Behaviour and Coevolution, 1990: 195-197.
MILLER, H.W., Niobrarateuthis bonneri,
a new genus and species of squid from the Niobrara
Formation of Kansas. Journal of Palaeontology,
NICHOLLS, E.L., and ISAAK, H., 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, 1987.
STEWART, J.D., and
CARPENTER, K,. Examples of
vertebrate predation on cephalopods in
the late Cretaceous of the Western Interior. Evolutionary Paleobiology
of Behaviour and Coevolution, 1990: 203-207.
TANABE, K., HIKIDA, Y., and IBA, Y., Two coleoid jaws from the Upper Cretaceous of Hokkaido, Japan. Journal of Paleontology 80 (1) 138-145, 2006.
Mike Everhart, Tracy Ford, Jean McKinnon, Dr Troy
Myers, Dan Varner, Chris Vencevich, Mark Montague (Monty).
Posted May 2004 -- Updated January 2006