SAUROPHAGANAX

When John Willis Stovall discovered some theropod dinosaur remains near Kenton, Oklahoma, in 1931 and named them Saurophagus (lizard eater) in an article by journalist Grace Ernestine Ray in 1941, he didn't nominate a holotype, even though he'd given himself a decade to pick one. A revisit by Lucas, Mateer, Hunt and O'Neill prompted the assignment of a tibia or shinbone (OMNH 4666) as lectotype—a retrospective holotype of sorts—in 1987. Then it all went pear-shaped.

In 1995, it was realised that the name Saurophagus had been assigned to a tyrant flycatcher (a "lizard-eating" bird) by William John Swainson 110 years earlier, and the lectotype tibia was tagged as non-diagnostic. With the remaining Kenton fossils up for grabs, Dan Chure nabbed a neural arch as holotype, salvaged whatever fossils were distinguishable from the same area's Allosaurus, cunningly replaced -us with -anax, and hey presto, Saurophaganax was added to the roll call of dinosaurs. Despite bearing an uncanny resemblance to the original name, Chure was quick to stress that Saurophaganax is not a like-for-like replacement for Saurophagus but an all-new critter in its own right. Ironically, Swainson's Saurophagus turned out to be synonymous with an omnivorous bird called Pitangus, which he had named himself in 1827.

At over ten meters long and close to four tons in weight, Saurophaganax was the largest carnivore in the Jurassic-aged Morrison Formation, outsizing both Allosaurus fragilis and Torvosaurus tanneri, and some even larger fossils of this most reclusive carnivore may have been discovered in New Mexico. Catalogued as NMMNH P-26083 and including a femur, several tail vertebrae and a hip bone, this new specimen of Saurophaganax should have proved once and for all that it isn't merely a huge specimen of Allosaurus (Allosaurus maximus) and douse the faintly-flickering theory that it may be the same as Epanterias.

Despite the lingering uncertainty, Oklahoma crowned Saurophaganax their official state fossil in 2000. Then prayed that this particular dinosaur adoption wouldn't end in tears. Take pity on Texas and their adopted "Pleurocoelus", which was renamed Paluxysaurus and adopted again just before the Mesozoic Moirai twisted fate once more, sinking it as a synonym of Sauroposeidon. Unfortunately, Saurophaganax was back in the limelight as the latest scrutiny of its fossils was published in 2024, and it wasn't good news.

According to Andy Danison and colleagues, the holotype of Saurophaganax is dubious, as it cannot be confidently assigned to a theropod or a sauropod, and thus it was in no position to accept referred remains from anywhere. The name could've been saved by invoking article 75.6 of the ICZN code and nominating a neotype from any of the confirmed gigantic Kenton quarry theropod fossils that Chure had assigned to Saurophaganax in 1995. But, alas, all of that material was instead referred to a new species of Allosaurus — a critter which is itself based on a dubious holotype replaced with a neotype — that they named Allosaurus anax. The potentially good news for Oklahoma is that their adopted Saurophaganax could come roaring back and smack Allosaurus anax down as a junior synonym if future studies confirm that its holotype belongs to a theropod.