So you think you know rhinos?

John Flynn, Frick Curator of Fossil Mammals at New York’s American Museum of Natural History, sent me this photograph (below), asking if I remembered the specimen depicted. A complete and well-preserved skull of Hyrachyus eximius, I recognized it immediately as the first notable specimen I ever collected for the Field Museum back in the summer of 1994, when I was a volunteer preparator and a novice – but very enthusiastic – collector of vertebrate fossils. I will never forget the thrill of that particular discovery.

Field Museum specimen P1020856, Hyrachyus eximius.
Field Museum specimen P1020856, Hyrachyus eximius.

I kept a somewhat prosaic journal that summer, which failed to capture the excitement of that first expedition to the Bridger Basin of southwestern Wyoming. Nevertheless, inspired by seeing the specimen again, I excavated the long-neglected journal from a dusty desk drawer. My entry for Monday, July 18 reads (in part):

Down in the badlands I find early discouragement. I am distracted, I find nothing, and I conclude that this area is destitute of fossils. Even the turtles are scarce…. I wander for another 30 minutes before I spot what appears to be limb fragments, but in fact turns out to be a toothless jaw frag[ment], quite large. It is black in color and stands out distinctly on the pale … butte. I trace a line above and below the specimen and find more fragments but little to be excited about. Below and downstream … in the dry wash I find 2 more fragments of the same color and of compatible size to be associated with the jaw. I put them in the same bag. Back at the butte I scrape the topmost weathered layer with the pick end of my hammer. Just under the surface I find more jaw frag[ment]s. I get out my awl and brush and I soon realize that I have a complete lower jaw. Next to the jaw I uncover what turns out to be a complete skull – it appears to me to be a camel. [Hyrachyus is actually a small rhino.] The rest of the afternoon, minus a sorry lunch that I share with Robin [Whatley] on a nearby hill, I spend in uncovering my specimen.

A beautiful restoration of Hyrachyus eximius from 1913 by R. Bruce Horsfall.
A beautiful restoration of Hyrachyus eximius from 1913 by R. Bruce Horsfall.

Fortunately for posterity, this episode was also recorded by my late friend and colleague Steve McCarroll. Steve published an entertaining account of the following day – when the specimen was finally collected – in the Field Museum’s membership newsletter, In the Field. Steve wrote:

Paul had found what he was calling a skull and said he would have to go back and collect it in the morning. This was Paul’s first summer collecting with us in Wyoming, and so John and I were a bit skeptical about his identification of the specimen as a skull. Specimens are often [found] crushed and covered with bits of rock, so field identifications are often changed back in the lab once the specimen is cleaned up.

Even so, the thought of finding a skull was exciting. A complete fossil skull is a very rare find, so John decided to take a look at the specimen…. All morning I had occasionally glanced over to the spot where John and Paul were crouched down over the ground, the spot, I assumed, where the “skull” was. As I waited I … reread some scientific papers…. But by 9:20 a.m. I had run out of things to do. I glanced one last time over at John and Paul and saw that John was no longer at the site. I walked over to the edge of the ridge … and saw John below just starting the long walk uphill…. Carefully cradled in his arms was a small block of rock. About halfway up the hill John looked up at me, a huge grin creasing his face, and said, “It’s really cool.”

From left to right: Robin Whatley, Steve McCarroll, John Flynn and me. I am tired and dehydrated from a tough day in the field.
From left to right: Robin Whatley, Steve McCarroll, John Flynn and me. I am tired and dehydrated from a tough day in the field.