Sauropods—the biggest

Contrary to what is the usual SOP, Wedel and Hallett, in their recent sauropod book (published August 2016—I'd guess the manuscript can't be more recent than late 2015 at the earliest.  But that's still newer than most books) make casual reference several times to Amphicoelias fragillimus and treat it as a valid (albeit missing) specimen as reported.

This is interesting, because in doing so, they basically acknowledge that it's probably the biggest dinosaur specimen that we know of.  There are a number of contenders for that title, of course, and most are based on very fragmentary remains, so a lot of speculation and assumptions have to be inferred.  Also; what does "biggest" mean?  Longest?  Tallest?  Most massive?

Anyway, here's an illustration which shows, of course, how little of the animal that we actually know; the rest is inferred from related species.  As an aside, this also shows what the proper neck posture most likely really was—the age of flat-necked sauropods is over (although there's still tons of illustrations out there that adhere to it.)

Anyway; what are some other contenders for "biggest" besides A. fragillimus anyway?

I've got a post I did a month or two ago talking about some of the contenders.  As far as I know, it's still both accurate and up to date.  http://darkheritage.blogspot.com/2017/10/big-dinos.html

Anyway, that list wasn't meant to be exhaustive, but if you read the text and see the dinos mentioned, I think the only ones that are really missing that should be mentioned are Alamosaurus and maybe Antarctosaurus and Futalognkosaurus dukei.  For longest, you've got a few other contenders that otherwise aren't on the list: Mamenchisaurus sinocanadorum, Supersaurus vivianae,  and maybe Turiasaurus too, although it's probably not as large as the others.

For good measure, you have to also consider the largest specimens from the very latest Morrison of Camarasaurus supremus, which is unusual, given that Camarasaurus lentus, the most common Morrison sauropod, is a rather modest creature.  C. supremus is a good contender for most massive dinosaur, however—assuming that it scales up.

It's funny; for years and years, I thought of sauropods as rather boring dinosaurs; the equivalent of really big cows or something.  In recent years—and not just because of the tremendous size of some of the newer discoveries (newer than my old Brachiosaurus is the biggest, Diplodocus is the longest kids' book days from the 80s or earlier anyway); they just had a lot going on, there is some surprising variety to them, and they aren't just an artifact of the old Jurassic anymore like I used to think.  In fact, many of the most interesting ones are considerably later than that, and the Cretaceous looks to have been a heyday of sorts for sauropods, which is in contrast to what I used to believe, when I thought that there weren't any sauropods from the Cretaceous.  (Give me a break; those kids books I read when I was a kid were massively dumbed down.)  While this is especially true for the old Gondwana continents, Asia and North America have their share of really awesome Cretaceous (even very late Cretaceous) sauropods.

There's still the inexplicable-seeming gap of about 40 million years in North America, though.  Between Sauroposeidon and Alamosaurus, we don't know of a single sauropod that lived on the continent.  Somehow that seems unlikely, but... you never know, I suppose.