More than a century and a half before Sir Richard Owen coined the word dinosaur in 1842, a quarryman digging into limestone beds in the Oxfordshire parish of Cornwell, England, unearthed a massive, petrified twenty-pound piece of rock that looked unmistakably like the lower knee-joint end of a colossal thighbone. Handed over in the 1670s to Dr. Robert Plot—Professor of Chemistry at the University of Oxford and the very first keeper of the Ashmolean Museum—this extraordinary specimen became the first dinosaur fossil ever illustrated and described in a printed scientific book in human history, even though Plot’s wildly entertaining explanation of what the bone actually belonged to went down in scientific folklore.
The 1677 Illustration in The Natural History of Oxfordshire
Born in Kent in 1640, Robert Plot was one of the leading natural philosophers of Restoration England: a Fellow and Secretary of the Royal Society who walked across English counties interviewing miners, farmers, and apothecaries to compile exhaustive encyclopedias of local geology, plants, and antiquities. In 1677, Plot published his landmark volume, The Natural History of Oxfordshire.
On Plate VIII of the book, Plot included a meticulous copperplate engraving of the mysterious giant stone fragment dug out of the Cornwell quarry (Middle Jurassic limestone dating back roughly 168 million years). Measuring nearly two feet in circumference and weighing twenty pounds, the specimen had the exact hollow marrow cavity, porous bone structure, and twin rounded lower condyles of the distal end of a giant femur (thighbone)—identified today by paleontologists as belonging to Megalosaurus, a thirty-foot carnivorous theropod dinosaur that prowled Jurassic England.
Mineral “Sports of Nature,” a Roman War Elephant, or a Biblical Giant?
Because nobody in seventeenth-century Europe had the faintest idea that giant reptiles had ruled the Earth millions of years before humanity existed, Robert Plot worked through three fascinating seventeenth-century hypotheses to explain what this giant petrified bone could be:
- Hypothesis 1 (Plastic Virtue of the Earth): Initially, like many Renaissance geologists, Plot wondered if the stone wasn’t an animal bone at all, but a lusus naturae (“sport of nature”)—a regular rock crystallized by minerals in the ground into the accidental shape of a bone. However, looking at the microscopic bone pores and exact anatomical contours of the specimen, Plot admitted it looked far too precise to be a random rock.
- Hypothesis 2 (A Roman War Elephant): Next, Plot reasoned that if it was a real bone, it had to belong to the largest animal ever brought to Britain: an elephant brought over during the Roman invasion of Emperor Claudius in 43 AD. Yet when Plot went down to examine an actual elephant skeleton displayed in Oxford and compared the measurements, he realized the Cornwell fossil was dramatically larger and differently shaped than an elephant’s femur.
- Hypothesis 3 (A Giant Human From Genesis): Having ruled out elephants, Plot arrived at his famous final conclusion: the bone must be the petrified thighbone of a real-life giant human man or woman of the sort mentioned in ancient scriptures and classical histories!
1763: How Richard Brookes Gave a Dinosaur the Funniest Name in Science
The story of Robert Plot’s dinosaur bone took an even more hilarious turn eighty-six years later in 1763. Although the actual physical fossil had been lost at the Ashmolean Museum in the early 1700s, the English physician and compiler Dr. Richard Brookes reprinted Plot’s 1677 engraving in his multi-volume work, A New and Accurate System of Natural History.
Looking closely at the drawing of the broken femur end—which featured two large, rounded, symmetrical lobes side by side beneath a broken cylindrical shaft—and remembering Plot’s conclusion that the fossil belonged to a giant human male, Brookes decided to apply Carl Linnaeus’s brand-new system of Latin binomial nomenclature to the picture. Thinking the two rounded bone condyles looked less like a knee joint and much more like a petrified pair of giant human testicles, Brookes solemnly labeled the illustration Scrotum humanum!
In the 1970s and 1990s, when paleontologists realized that Brookes’s 1763 Latin binomial name Scrotum humanum technically predated William Buckland’s 1824 naming of Megalosaurus by sixty-one years under the chronological rules of zoological nomenclature, the International Commission on Zoological Nomenclature had to step in and officially rule Scrotum humanum a forgotten invalid name (nomen oblitum)—saving the dignity of the world’s first discovered dinosaur while cementing Robert Plot’s place as the accidental grandfather of dinosaur paleontology.
