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Livyatan melvillei

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By theropod1   |   Watch
Published: September 13, 2015
Life reconstruction of this giant Miocene sperm whale, based on the related stem-physeteroid Brygmophyseter.
With proportions as restored here, the total length of the holotype individual is 15.4m. With the accompanying volumetric model yielding an estimated mass of ~51t, it turned out very robust in built, similar to some extant cetaceans.

Similar to extant orcas, these basal physeteroids were macrophagous predators of large vertebrate prey (e.g. other whales), and probably among the apex predators of their time.
This is supported by the presence of large, enamel-bearing teeth in both the mandible and the upper jaw, a robust cranial morphology and large temporal fossa, features on which they converge with extant macrophagous delphinids. The presence of exostoses adjacent to the teeth of the related Acrophyseter deinodon are signs of activity-related bone remodeling as a consequence of habitual powerful biting (Lambert et al. 2014).

Feel free to leave a comment and let me know your thoughts and suggestions!

Methods:
Modified skeletal and silhouette multiview restoration
I estimated postcranial axial length of the holotype of Brygmophyseter shigensis based on the table of vertebral measurements and the lateral-view photograph of the skeletal cast (p. 23, Plate 8) in Kimura et al. (2006).
The lengths of incomplete vertebrae were estimated based on the adjacent ones, or missing epiphyses were added based on the size of those in more complete vertebrae from adjacent positions. Intervertebral cartilage was measured as restored in the tail and lumbar region of the cast (where it was not obscured by ribs), and this percentage was applied to the entire post-cervical vertebral collumn in order to get an estimate of the in-vivo length that corresponds to the figured skeleton. Based on the above methodology, postcranial length (including the neck, also based on photo measurements) is about 4.2m.

Thanks to :iconblazze92: for providing valuable imput during this and later stages!
The ribs of the reconstruction were rotated for a more streamlined, life-like thorax, but space for the sternal complex (not figured) was left beneath the ventral end of the dorsal ribs.

The relative size of Livyatan, to which the postcrania of Brygmophyseter were fitted, bases on their relative bizygomatic skull widths. My measurements from fig. 5a and fig. 7a in Hirota & Barnes 1994 were within less than 1.5% of each other, at 70-71cm,consistent enough to suggest accuracy of the scalebars. Using the mean of those, Livyatan has a skull 2.79 times as wide (197cm, Lambert et al. 2010), and it is herein assumed that postcranium scales isometrically with bizygomatic width. The entire skeleton was scaled based on its digitally-measured axial length, and the skull replaced with that of Livyatan.

Soft tissue bases primarily on the extant Physeter macrocephalus, but with the addition of a larger fin and flippers, in a semblance of other active, macrophagous cetaceans (note that these were not included in the 3D model since their size and thickness would have been con. Their impact on the animal’s overall mass is unlikely to be significant).

Based on this reconstruction, and again incorporating data from extant sperm whales, I produced a 3D model in blender to estimate its body volume:
Blender model, multiview
The result being a volume of about 50.8m³, which,given a density of 1000kg/m³, as would be expected in aquatic animals, corresponds to the same number of tons (1t=10³kg).
A bulky bodied animal, with a mass[kg]/length[m]³-ratio of 14.01, it compares favourably to the largest macroraptorial animal alive today, Orcinus, where it averages ~14.35 (source), and to the related pygmy and dwarf sperm whales Kogia spp., whose published records (Long 1991, McAlpine et al. 1997, Scott et al. 2001, Stamper et al. 2006, link) indicate an average of ~14.63.

All in all, a considerable amount of work went into the research done for this reconstruction, and I am rather pleased with how it turned out, but I will continue to update this reconstruction and seek for ways to improve it. Any help doing so is appreciated. That doesn’t mean rude and baseless comments are, but I am not in the habit of deactivating comments just because some people can’t behave.

UPDATE: 14/10/2015: Adapted the dorsal view of the silhouette and 3D-model to match the proportions of Physeter. Drawing of dorsal view will also need an update based on that.

UPDATE: 11/12/2015: Finally came round to scanning my new reconstruction taking the aforementioned revisions into account, and also experimenting with an altered colour-scheme.

References:
Hirota, Kiyoharu; Barnes, Lawrence G. (1994): A new species of Middle Miocene sperm whale of the genus Scaldicetus (Cetacea; Physeteridae) from Shiga-mura, Japan. The island Arc, 3 (4), pp. 453-472.
Kimura, Toshiyuki; Hasegawa, Yoshikazu; Barnes, Lawrence G. (2006): Fossil sperm whales (Cetacea, Physeteridae) from Gunma and Ibaraki prefectures, Japan; with observations on the Miocene fossil sperm whale Scaldicetus shigensis Hirota and Barnes, 1995. Bulletin of the Gunma Museum of Natural History, 10 pp. 1-23.
Lambert, Olivier; Bianucci, Giovanni; Beatty, Brian L. (2014): Bony outgrowths on the jaws of an extinct sperm whale support macroraptorial feeding in several stem physeteroids. Naturwissenschaften, 101 (6), pp. 517-521.
Lambert, Olivier; Bianucci, Giovanni; Post, Klaas; Muizon, Christian de; Salas-Gismondi, Rodolfo; Urbina, Mario; Reumer, Jelle (2010): The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru. Nature, 466 (7302), pp. 105-108.
Long, Douglas J. (1991): Apparent predation by a white shark Carcharodon carcharias on a pygmy sperm whale Kogia breviceps. Fishery Bulletin, 89 (23) pp. 538-540.
Mcalpine, Donald F.; Murison, Laurie D.; Hoberg, Eric P. (1997): New Records for the Pygmy Sperm Whale, Kogia Breviceps (physeteridae) from Atlantic Canada with Notes on Diet and Parasites. Marine Mammal Science, 13 (4) pp. 701-704.
Scott, M. D.; Hohn, A. A.; Westgate, A. J.; Nicolas, J. R.; Whitaker, B. R.; Campbell, W. B. (2001): A note on the release and tracking of a rehabilitated pygmy sperm whale (Kogia breviceps). Journal of Cetacean Research and Management 3 (1) pp. 87-94.
Stamper, M. Andrew; Whitaker, Brent R.; Schofield, T. David (2006): Case Study: Morbidity in a Pygmy Sperm Whale Kogia breviceps due to ocean-bourne Plastic. Marine Mammal Science 22 (3) pp. 719-722.
Image size
4775x3257px 4.29 MB
IMAGE DETAILS
Make
Canon
Model
MP190 series
Software
GIMP 2.8.14
Comments31
anonymous's avatar
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KaprosuchusDragon's avatar
KaprosuchusDragonHobbyist Digital Artist
i like bothe the version you replaced with this and this :D
theropod1's avatar
theropod1Student Traditional Artist
And thanks for the faves and the watch btw!
KaprosuchusDragon's avatar
KaprosuchusDragonHobbyist Digital Artist
np ;)
theropod1's avatar
theropod1Student Traditional Artist
Thanks! Yeah, I sort of like the new colouring better, it somehow looks more realistic to me.
KaprosuchusDragon's avatar
KaprosuchusDragonHobbyist Digital Artist
hey i using the livyatan shilluete you made to draw a lyviatan is it ok that i post it with a link to the shiluette?
theropod1's avatar
theropod1Student Traditional Artist
Sure, totally fine!
KaprosuchusDragon's avatar
KaprosuchusDragonHobbyist Digital Artist
k first im drawinga nother cute alpha predators with megalodon and livyatan
theropod1's avatar
theropod1Student Traditional Artist
Cool, I’m curious to see what these two look like in cute :D
KaprosuchusDragon's avatar
KaprosuchusDragonHobbyist Digital Artist
yeah probaly done today i hopeBucktooth 
KaprosuchusDragon's avatar
KaprosuchusDragonHobbyist Digital Artist
i like the new colours they are cool
SpinoInWonderland's avatar
Nice color scheme.

I still think it would be slimmer though, like a sperm whale, but that's just my opinion.
theropod1's avatar
theropod1Student Traditional Artist
Thanks.

A reconstruction based on Physeter is being planned, I just couldn’t find the time so far. This one is also like a sperm whale; a pygmy sperm whale, which has proportionately long ribs similar to Brygmophyseter.
SpinoInWonderland's avatar
I'd like to see what you come up with :) (Smile)
theropod1's avatar
theropod1Student Traditional Artist
Have a look! :)
SpinoInWonderland's avatar
I just did. I fully agree with it. ~14ish meters and ~30-40 tonnes seem just about right.
Shaochilong's avatar
Are you sure you know what the cranium of Livyatan looks like? Because when you described it as having a "lower jaw considerably thinner than the upper jaw", it sounds like you're thinking of the skull of Physeter. Which is not the same as the skull of Livyatan 
the skull of Livyatan actually has a fairly large mandible relative to the cranium : img4.hostingpics.net/pics/5433…

And here is the much narrower cranium of Physeter:
 upload.wikimedia.org/wikipedia…;

I'd sure like to see your more "realistic depiction" of Livyatan with a deformed and dislocated mandible. 
Ovleg's avatar
I still can't buy the reconstruction based on the guessed fleshed unreliable mount of Brygmophyseter. There is a reason why Lambert et al. didn't reconstruct Livyatan with it despite the availability of this mount.
theropod1's avatar
theropod1Student Traditional Artist
Have fun. I'm looking forwards to seeing your vision of an animal closing its mouth with it's jaw in disarticulation...
Dinopithecus's avatar
I have more questions (sort of relevant).

How much ramming is required for an odontocete to kill something similar in size to themselves? It takes some amount of time, doesn't it? Also, do you think it would be as effective on a much smaller size scale?
theropod1's avatar
theropod1Student Traditional Artist
Yes, it seems to take some amount of time. When killer whales use it for killing large whales, they ram their prey repeatedly.

I think it becomes potentially more potent the larger the animal gets, due to the square cube law (kinetic energy grows to the third power given that the animal doesn’t get slower, which it doesn’t necessarily do in water, while the tissue’s resistance to rupturing or fracturing only grows to the second power).

As long as its head is still capable of adapting to cope with the stresses that is, which I think is the case in large otontocetes (looking at sperm whales, of course).

E.g. No matter its adaptions for doing so (which wouldn’t even be necessary on such a small scale), one guinea pig ramming another guinea pig won’t really do any damage, but one orca ramming another orca or one sperm whale ramming another sperm whale is a different story.
asari13's avatar
asari13Hobbyist Traditional Artist
nice
theropod1's avatar
theropod1Student Traditional Artist
Thanks!
anonymous's avatar
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