What is Nedoceratops? That depends on who you ask. The single known skull could represent a transitional growth stage between Triceratops and Torosaurus head shapes in a single species of dinosaur, or it might be
The suggestion that Nedoceratops was truly a Triceratops caught in the act of rearranging its skull has sparked a renewed interest in this dinosaur. Though known to paleontologists for over a century, the dinosaur was often viewed as an oddball and did not even receive a full redescription until about a month and a half ago. Nedoceratops has never been as popular or well-known as its relatives Triceratops and Torosaurus, and so I was surprised to learn that a life restoration had once been made of this peculiar creature.
A paper on the restoration accompanied a 1905 scientific description published by Richard Swann Lull but mostly written by John Bell Hatcher. This was not a bit of scientific claim-jumping. Hatcher had been working towards completing a massive monograph on horned dinosaurs. It had been started by his former boss, O.C. Marsh, who died of typhus before he could finish the book. The task of wrapping it all up went to Lull, who decided to publish Hatcher's description of the Nedoceratops skull separately in 1905. (At the time, Lull proposed that the dinosaur should be called Diceratops, though the name has been changed multiple times.)
Lull's restoration was of a battered animal. Unlike other horned dinosaurs, Nedoceratops had two unequally-shaped holes in the squamosal bones on the sides of its frill. Hatcher thought these might be natural holes in the skull, but Lull argued that, since Triceratops, Torosaurus and Nedoceratops undoubtedly used their horns and frills like spears and shields, "It seems vastly more probable that are 'old dints of deep wounds' received in combat." The animal survived the presumed injury, and Lull thought some kind of "horny or leathery integument" would cover the gaps in the frill.
We now know that Lull was probably wrong. When I asked paleontologist Andy Farke—who redescribed the skull—what he thought about the strange skull holes of Nedoceratops, he replied:
The old thought was that these holes were the result of accidental “gorings” during horn-to-horn combat between rival dinosaurs. But, Darren Tanke and I recently noted that most aspects of the fenestrae argue against them being the result of injury. Instead, we think they were probably just the result of bone resorption in an area of the frill that was already thin to begin with. No horn thrusts required.Even so, Lull's restoration is remarkable. I cannot recall seeing any other model or sculpture of Nedoceratops, and it is a rare vision this contentious dinosaur in the flesh.
Farke, A. (2011). Anatomy and Taxonomic Status of the Chasmosaurine Ceratopsid Nedoceratops hatcheri from the Upper Cretaceous Lance Formation of Wyoming, U.S.A PLoS ONE, 6 (1) DOI: 10.1371/journal.pone.0016196
Lull, R.S. (1905). Restoration of the horned dinosaur Diceratops. American Journal of Science, 4 (4), 420-422