The Biggest - Puertasaurus reuili by Paleo-King

They seem to have gotten wide due to needing a longer and more efficient digestion, either because of changes in the cretaceous plants (i.e. more toxic?) or as a response to more extreme seasons and more volatile food supply. Funny thing is, we don't know how much longer they could have gotten. The Puertasaurus holotype probably wasn't even the longest.

The mobile island theory is tempting but probably off. Titanosaur legs and feet get more robust in their evolution just as their bodies do. These animal's limbs were evolving to support more mass for their length, so judging by their skeletons, they were not becoming aquatic in any sense. Other sauropods probably didn't have any trouble floating even with a slimmer body. None of them were semi-aquatic, but all were capable of floating and swimming - elephants can swim just fine, and sauropods had more attachment points for limb muscles, so likely more precise movements. The overall density of sauropods was, ton for ton, less than most other animals because of all the air sacs in their bones. This was true of brachiosaurs, diplodocoids, mamenchisaurs, etc. just as it was for titanosaurs.

Chris Masna actually did that part. I designed the Puertasaurus.

Also, hummingbirds are dinosaurs by definition, as all birds are highly derived theropods from the coelurosaur line.

Thanks very much!

Amphicoelias is totally valid - in the sense of it being a valid genus with valid type material. However the type material (Amphicoelias altus) is from an animal no bigger than Diplodocus.

Amphicoelias fragillimus, the near-mythical giant vertebra that got lost, was only about 40% of the vertebra (if the published drawing can be believed) but based on that a 2m+ tall reconstruction has been drawn for the full bone by both Cope and Ken Carpenter.

For being a bone that no longer exists, it's definitely extremely popular. But the fact is, this isn't the biggest dinosaur we have currently existing fossil proof for. If more bones are ever found, it may actually need its own genus separate from Amphicoelias, the proportions are a bit different from A. altus, but not enough to definitively erect a new genus. The problem with this animal is not so much its validity (the bone is no longer around to analyze) but the fact that it's so poorly documentes (a single paper from Cope, and it isn't even the main focus of the paper). Cope could have made a scaling error, or a typo. The discovery was so obscure that for nearly a century nobody paid it any attention in major paleo-journals. So the real issue is that it wasn't really a big deal until the 1990s (and until the 1980s even PhDs thought there was nothing bigger than Brachiosaurus, despite larger and more massive sauropods (some still as yet undescribed) being known from Argentina since the 1920s (and possibly even since the late 1800s).

That said, there are some footprints scattered around the planet that could have been made by an A. fragillimus-sized creature. None of them are in the Morrison, but that doesn't rule out their discovery. But when you scale off of footprints, you really run into some serious problems. Unless you can scale a bigger animal from the same family off of bones, I'd avoid scaling from footprints, just don't do it! There's too much margin of error either way, either from splaying of the heel pads, or conversely from prints with caved-in edges that are too eroded to tell if they caved in. (for Breviparopus, I kept in mind that "Brachiosaurus" nougaredi can actually be scaled to a larger size based on a pretty huge partial sacrum, so Breviparopus is not a record-breaker even in Brachiosauridae - or even if you put it in another family.)

The average blue whale is less than 65 tonnes in mass, it's not larger at all than Puertasaurus.

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Blue whales were nowhere near the actual largest animal that ever lived title.

The problem is that people commonly take the largest specimens as the only figures while ignoring the plethora of more average specimens.

It may look thin from the side, but when viewed from the front [link] , it's very wide. Puertasaurus didn't have a thin neck, it just had very odd proportions and the neck's cross-section was very squat.

Thanks very much! Yes R2D2 really helps make this picture catchy. At some point Puertasaurus will get the recognition it deserves and Argentinosaurus will probably no longer be "the biggest" in popular opinion/dinosaur fandom (it already isn't in reality). And I think this poster will be one of the main reasons why.

Thanks! It was a lot of work, but both Chris and myself are glad at how well it turned out

For scale.

I reached that posture based on part speculation from the shape of the 9th neck vertebra (the only one preserved) and part comparison with related, more complete titanosaurs. Given the extreme squatness of the neck's centra, a big range of vertical motion was possible, so there are many inclines and degrees of curvature that are possible with this neck, I just illustrated one of the more conventional non-feeding possibilities.

You're very welcome + Kudos to Chris for doing the 3D render.

Actually it's not that black and white. The family tree is based on my own research of the material (I have close to a hundred titanosaur papers, most of which are either descriptions or redescriptions). Currently my analysis uses a number of characters that to my knowledge have not been included in most cladistic analyses. I do have a data table with characters, however I have not yet had time to publish it. If you want to ask about specifics (for example "how is Trigonosauridae a valid clade, what unique derived characters do they have") you can email me for details but I can't give everything away just yet. My photographic stash of image of titanosaurs bones is vast beyond all expectations, and I've collected images of every titanosaur discovery for the past 10 years. Both official published images and otherwise. Over the past 2 years I have compiled my data, there is still much to be done before publication however and since paleontology is not my day job there are more pressing priorities. However the trends in this data appear rather strong, and many characters I found have been totally ignored by the few large phylogenetic studies of titanosauria.

Keep in mind our understanding of titanosaur evolution is still in its infancy. This family tree in its current version may turn out to be incorrect on some points; but it's incredibly doubtful to me that most of the clades you mentioned are wrong. In particular Acrofornica and Trigonosauridae are very distinct and tight-knit clades whose members can not be comfortably placed anywhere else. I accept that it may need to be revised in the future, after all that's what science is all about. But it's definitely not made on a whim, and I doubt that the entire thing will ever be falsified. Keep in mind that most of the family trees which predominate in the current research are completely different from each other as well (compare McIntosh with Wilson and Upchurch, and even among their findings alone, and depending on the statistical method used the phylogeny will arrange itself as many as 15 different ways)

BTW I am not creating "nomina nuda" as I am not inventing any new taxa here. A "nomen nudum" is by definition a name used for an individual taxon (i.e. genus or species) rather than a general term denoting a probably family or clade. Remember that there is no such thing as a "naked clade" so long as at least its namesake is a valid species with a description.

Yeah when you live in water you can get a lot heavier than land animals and still not be crushed by your own mass (unless you get stuck on a beach). Blue whales can weigh up to 200 tons, and they filter their food more or less effortlessly out of the same water that surrounds them, instead of browsing or hunting for it. Talk about cheating lol!

Actually that estimate is at least 10 years out of date. David Gillette originally estimated it at around 130-150 ft. long, but this was only a preliminary (and very overblown) guess. Seimosaurus was more recently reexamined, by Dr. Ken Carpenter, Scott Hartman and others, and has been rescaled to 110 ft. long. In fact Greg Paul back in 1994 already had reconstructed it at around this length. It's not hard to gauge its real size, most of the skeleton is actually known. And it's smaller than Gillette estimated.


Even if Seimosaurus were 150 ft. long, would still be a lot lighter than any of the really big titanosaurs. Diplodocids are mostly pretty light for their length, essentially just a huge tail on a slim, compact body that appears to be from a much smaller animal.