2006 Gregory Award Recipient
John R. Bolt
John R. Bolt is currently Curator of Fossil Amphibians and Reptiles in the Department of Geology, Field Museum, and formerly Department Chair. He served for 5 years as Treasurer of the Society of Vertebrate Paleontology; during that time and continuing to the present he has also been either Chair or Member of the Financial Oversight Committee. His election as Treasurer represented a departure from the previous practice of electing a single Secretary/Treasurer. This change represented a recognition that the Society’s growing membership and increasing complexity required separation of the Secretary/Treasurer’s functions. These factors also led, during John’s tenure as Treasurer, to a number of changes in the Society’s business operations including the decision to employ an association-management firm.
As an undergraduate in Geology at Michigan State University, John decided on a career in vertebrate paleontology. In his senior year he was accepted into several VP programs including those at the University of Chicago and the University of Michigan. The latter explains how he came to spend a summer in the Pleistocene of (mostly) Meade County, Kansas with Claude Hibbard’s field crew, which that summer included Margaret Stevens and Rick Zakrzewski.
Following this summer in Meade County, John began graduate work with E. C. Olson at Chicago. Field work with Ole in the Lower Permian of north Texas was a revelation to a Midwestern boy: this had to be the hottest place on Earth, at least in July. John had no sooner decided to do a thesis on some Lower Permian tetrapod(s), than a project found him. A commercial collector had sent Ole some tiny tetrapod specimens for identification. These came from the famous Lower Permian Fort Sill fissure fills in SW Oklahoma, and their state of preservation was amazing despite the fact that they had been prepared with an Air-Dent. John determined that they looked like dissorophid temnospondyls, but the dentition was unique: all specimens were missing crowns, yet the tooth bases looked as though they had all been planed off at the same height, not broken. By coincidence Parsons and Williams had recently published their work on modern-amphibian relationships, emphasizing the unique bicuspid and pedicellate teeth of lissamphibians. Collecting trips to Fort Sill soon resulted in much more material, and definitive association of lissamphibian-type teeth with this little dissorophoid temnospondyl. John named the new taxon Doleserpeton annectens, and argued that it supported earlier suggestions of a relationship between dissorophoids and the origin of lissamphibians. This work was the beginning of John’s long-standing interest in dissorophoids, the origin of lissamphibians, and the fauna of the Fort Sill deposits.
After graduation from the University of Chicago, John spent several years at the University of Illinois Medical Center, which he left for a position at the Field Museum. Together with Bob DeMar he began work on patterns of tooth replacement in polyphyodont vertebrates, especially Paleozoic tetrapods. The multiple-tooth-rowed captorhinomorphs presented a particularly interesting problem: it was obvious that these animals had replacement, but the mechanism was not clear. A histological study with Armand de RicqlÃ¨s, of Captorhinus aguti (another Fort Sill species) suggested an answer. C. aguti apparently used a system involving growth of the dentary medially, with addition of new teeth, and loss of teeth laterally due to bone remodelling.
Continuing his interest in lissamphibian origins, John began discussing the subject with Eric Lombard, of the Department of Organismal Biology and Anatomy at the University of Chicago. Their intent to study the evolution of the anuran ear was expanded into a general study of the evolution of the tetrapod ear. The anuran-ear paper they had initially contemplated appeared several years later, and proposed that anurans are most closely related to dissorophoids. This was followed by a paper on the evolution of the stapes, and John and Eric have continued to collaborate on other studies.
Although most of John’s field work has been in the Lower Permian of the southwestern US, with excursions into the Triassic, he always wanted to collect Mississippian or Devonian tetrapods. He is still waiting for the Devonian opportunity; but he got a chance at the Upper Mississippian, thanks to the generosity of the Iowa Geological Survey. This was a locality near the town of Delta in SE Iowa, an abandoned quarry that has produced hundreds of specimens of tetrapods and “fish.” The latter led to John’s first non-tetrapod paper, a study of the lungfish Tranodis castrensis with Hans-Peter Schultze. The most abundant species at Delta is a stem tetrapod christened Whatcheeria deltae by John and Eric Lombard. They have since published other studies on the Delta fauna, and their work on this fascinating fauna continues. John feels very fortunate to have the chance to collect and study one of the few Mississippian tetrapod localities in the world, and is excited about continuing this and other projects.
Photo courtesy of John R. Bolt.