VENENOSAURUS

Being that venomous critters generally use their poison as a means to incapacitate something that they wish to eat, the "veneno" of Venenosaurus—from the Latin venenum meaning poison—may seem like a strange word to be attaching to a strict vegetarian, even one that's 12 meters long. And it would be. But it all makes sense when you look at its place of discovery: the Poison Strip Member of Utah's Cedar Mountain Formation, where Anthony DiCroce discovered its fossils in 1998. So the search for a toxin-crippling dinosaur continues. Humphh.

Venenosaurus, formally described in 2001, represents a gracile titanosauriform—a lightly built member of a group of long-necked plant-eating sauropods—from the Early Cretaceous, roughly 112 million years ago. Its partial skeleton—comprising vertebrae, limb bones, and pelvic elements—reveals a creature more lightly built than the barrel-bodied Camarasaurus, yet not as slender as Cedarosaurus, with which it shared its stratigraphic neighborhood. Its hand bones are long and slim, the forearms proportionally delicate, and the tail vertebrae display unusual side fossae (depressions or cavities). But unlike the fossae on most sauropods, which led to chambers for air-sacs to lighten their skeletons and enhance respiratory efficiency, these were merely deep depressions divided by internal ridges, hinting at a less specialized breathing system. The vertebrae also boast articulations not reported in any other sauropod.

In short, Venenosaurus is the kind of awkwardly gorgeous fossil that keeps paleontologists honest: fragmentary enough to provoke questions, rich enough to suggest answers. It borrows the long-armed look of brachiosaurids and flashes pelvic and vertebral traits that nod toward titanosaurs, yet refuses to commit to either identity. That half-and-half quality provides a valuable glimpse at titanosauriform experimentation—a snapshot of evolution in the act—and a reminder that Early Cretaceous localities like the Poison strip still have stories left to tell.