Largest animal by geologic period

[BlueKrono]

I've been trying to compile a list of the largest animal of each geologic period. The recent article about the resizing of Dunkleosteus had me wondering about how it stacked up against the giants of other eras. Sorry it's in feet and inches, but it's still useful for comparison.

Precambrian - Dickinsonia 4'7"
Cambrian - Omnidens 4'11"
Ordovician - Aegirocassis 6'11"
Silurian - Acutiramus 6'11"
Devonian - Dunkleosteus 13'5"
Carboniferous - Helicoprion 26"3"
Permian - Prionosuchus 18'4"
Triassic - Shonisaurus 68'11"
Jurassic - Supersaurus 148'0"
Cretaceous - Bruhathkayosaurus 121'0"
Palaeogene - Basilosaurus 65'7"
Neogene - Megalodon 65'7"
Quaternary - Blue whale 99'0"

[Stegotyranno420]

This is an awesome idea and I wish it was utilized before. But it seems odd to include bruthakyosaurus. Still a fun list

[Lynx]

The fact that there were only two eras where the largest creature was a terrestrial creature amazes me.

[Stegotyranno420]

The fact that there were only two eras where the largest creature was a terrestrial creature amazes me.

*The largest known 

[Faelrin]

I've heard of all of these except Bruhathkayosaurus. Too bad the remains were fragmentary, and supposedly destroyed.

[dinofelid]

Cool idea! There's an artist on deviantart called Dragonthunders who's done a bunch of size charts for different periods up through the Devonian (he talks about the reason he hasn't yet done the Carboniferous or later in this twitter thread where he also mentions he got some info wrong in the Precambrian chart, updated work-in-progress here), so I looked at those to see if there were any bigger ones than what you have. In the Ordovician, there's Endoceras which does seem to have been gotten than Aegirocassis, the wiki articles gives a source for an estimate of 18.7 feet. In the Silurian, there's the crinoid Scyphocrinites, the artist references this paper (you can get around the paywall by using a sci-hub link) which says on p. 2 that "Scyphocrinoids have a stem as long as 3 m, an ∼10-cm-high calyx, with large interradial areas comprising fixed small plates and pinnules (for Scyphocrinites see Ubaghs 1978a: Fig. 292; for other closely related lobolith-bearing genera, such as Marhoumacrinus, Carolicrinus, and Camarocrinus see Hess 1999: Fig. 112; Haude et al. 2014: Fig. ". But these guys were sessile, attached to the sea floor, maybe you want to focus on motile animals?

For the Devonian, the new study that downgraded the largest Dunkleosteus to 4.1 m also suggested Titanicthys needed to be downgraded too, but it might have been slightly larger--if you click "download" button to get the full pdf, p. 44 gives an estimate of 4.15 m, though they say "Admittedly, the range of body sizes spanned by Titanichthys is not as clearly defined as Dunkleosteus be- cause remains of this taxon tend to be fragmentary [22], but Titanichthys appears to have been similar in size or only slightly larger than Dunkleosteus." Heterosteus might beat both of them in the Devonian, the wikipedia article gives a body length of up to 6 m.

On the twitter thread I linked above, the artist posted this work-in-progress size chart for Permian and Triassic which indicates some sharks in the Permian that were larger than the amphibian Prionosuchus, the twitter threads here and here indicate he has Parahelicoprion as the biggest Permian shark, the wiki page gives an estimate of 12 m. Also the wiki article on Helicoprion seems to say it's currently thought to have only lived in the Permian, not the Carboniferous as on your list, though there was one fossil from the Carboniferous that was reclassified: "In 1922, Karpinsky named a new species of Helicoprion, H. ivanovi, from Gzhelian (latest Carboniferous) strata near Moscow. However, this species has subsequently been removed from Helicoprion and placed as a second species of the related eugeneodont Campyloprion.[23]"

On that last twitter thread he also shows the Carboniferous fish Edestus as bigger than Campyloprion, so that might be the biggest one known to have lived in the Carboniferous--like many cartilaginous fish the body beyond the skull isn't know, but the wiki article says "Based on a 5:1 body length to head ratio, this suggests that individuals of E. heinrichi could reach lengths of 6.7 m.[4]" This article also mentions an unnamed Carboniferous shark that may have been up to 7 meters, based on the size of part of the braincase. Saivodus was another large Carboniferous shark known only from teeth but estimated in the wiki article to be up to 9 m. And in this tweet the artist mentions a Carboniferous fish known only from 10 cm teeth, Orodus ramosus, and says that "this scaled with complete specimens scales to sizes bewteen 12 to 15 meters".

For Supersaurus, where does the 148-foot estimate come from? This post from a paleontologist describes a recent study saying that "My conclusion, published in the Society of Vertebrate Paleontology annual meetings, is that it  exceeded 128 feet (39 m), and likely was 137 feet (42m) from nose to tail". Finally, if you're doing the largest individual rather than the average size for a species, the blue whale should be bigger, this page says "The longest blue whale on record is a female measured at a South Georgia whaling station in the South Atlantic (1909); she was 110' 17" (33.58m) long."