AMPHICOELIAS

Amphicoelias altus, a diplodocid around 18 meters long and 18 tons in weight, was named by palaeontologist Edward Drinker Cope in December 1877 for two vertebrae, a pubis (hip bone), and a femur (upper leg bone) discovered in stratigraphic zone 6 of Colorado's Morrison Formation. But the real story lies with a much larger species...

Amphicoelias fragillimus

Amphicoelias fragillimus was shaping up to be the biggest dinosaur ever, and eclipsed even the Blue Whale in length when applying proportionate upscaling based on better-represented relatives to Edward Drinker Cope's sketches of a partial colossal vertebra found by Oramel Lucas at Colorado's Garden Park in 1877. Unfortunately, despite its humongous size, it was "misplaced" along with an equally huge partial femur found a short distance away, and all attempts to locate it have been in vain.

It's not beyond the realms of possibility that Cope, obsessed with one-upping his arch rival during their infamous machismo-driven bone wars, was telling fibs. But reputations were at stake, and the fact that Othniel Charles Marsh, who often sent spies to keep tabs on Cope and his discoveries, didn't publicly question the measurements of his find speaks volumes for its validity. Given its "fragillimus" state and a lack of fossil-hardening preservatives available at the time, it may have just crumbled to mush where it lay.

In 1921, Amphicoelias fragillimus was provisionally synonymised with Amphicoelias altus by H.F. Osborn and C. C. Mook, who noted similarities to Diplodocus. Then, in 2007, John Foster rocked palaeontology to its core when he suggested that these similarities were actually identicalities and that Diplodocus should probably be synonymised too. The cross-section of the thigh bone, which palaeontologists clung to as a means to separate Amphicoelias altus from Diplodocus, is now known to occur in Diplodocus too, and if they do represent the same critter, then the latter name would be sunk as the former was coined first.

The vertebra of Amphicoelias fragillimus, however, sports features not found in either Amphicoelias altus or Diplodocus and is no closer to one than it is to the other. Separated at the species level by Cope, the former may actually represent a different type of sauropod entirely, but before it can be granted its own name, the original remains need to be pinpointed for closer scrutiny, and the chances are slim... or so you might think.

Despite opining the difficulty in confirming its taxonomic validity without the holotype in hand for further study and the holotype remaining well and truly lost, Kenneth Carpenter renamed Amphicoelias fragillimus to Maraapunisaurus in 2018, reclassified it as a rebbachisaurid, and revised its vertebrae to a less spectacular 2.4 meters in height which, based on the proportions of its new-found family members, scythed close to 50% off its popular estimated body length of 58 metres. Amphicoelias latus was found at the same site as Amphicoelias altus, whose name is virtually identical. It is possible that Cope confused himself and accidentally flip-flopped the first two letters of their epithets as he scribbled their names in his notebook, but he did assign the former its own holotype (AMNH 5765); four caudal vertebrae and a right femur which, despite being extraordinarily robust, has been misplaced. Nevertheless, the bits that were available to study are closer in form to those of Camarasaurus than to those of Amphicoelias, which led Osborn and Mook to assign them to Camarasaurus supremus in 1921. However, it appears to have more in common with Camarasaurus grandis. In 2010, a monograph was made available (but not formally published) by Henry Galiano and Raimund Albersdorfer in which they referred a new species to Amphicoelias—Amphicoelias brontodiplodocus—based on several complete specimens found in the Dana Quarry of Big Horn Basin. Shockingly, this "paper" sunk every Morrison formation diplodocid plus a few from elsewhere into Amphicoelias altus, and the only other diplodocid the authors considered valid was their new and ridiculously named critter—literally "Both sides hollow thunder double beam". Unsurprisingly, this theory didn't receive much support from palaeontologists, which in hindsight was justified. In exchange for a bagful of cash, a specimen named "Sleeping Beauty" found itself mounted in a Dubai shopping centre in 2014 with the unbelievably mundane "DubaiDino" hanging around its neck after Saudi banker Johara Al Bayedh won a naming contest sponsored by the Emaar Malls Group. And guess what? It's a confirmed species of Diplodocus longus, the only mounted specimen made up entirely of original fossilised bone, no less. It's such a shame that kids will be monkey-swinging from its ribs and carving their names into its toes while it should be in a museum, undergoing serious scientific study.