A recently published groundbreaking caecilian fossil discovery made by Ben Kligman, Virginia Tech PhD candidate, and his phenomenal colleagues not only graced the cover of Nature journal this month, but also honored one of the Academy’s very own scientists.
We reached out to the lead author to learn more!
What is a caecilian, and why do their fossils matter?
Today’s amphibians are represented by three major groups: frogs, salamanders and the limbless worm-like caecilians. We know relatively little about caecilians compared to frogs and salamanders — most species live underground, burrowing in the soil and leaf litter of tropical forests, making scientific collection and observation difficult. This cryptic lifestyle also produced an exceptionally sparse fossil record of extinct caecilians that further obscures our understanding of their present-day biology and their evolutionary history.
Prior to our study, only ten fossil caecilian occurrences were known, dating back to the Early Jurassic (~183 million years ago); however, DNA studies have estimated their evolutionary origins in the Carboniferous or Permian (~370 to ~270 million years ago), leaving a gap of at least 87 million years in which caecilians should exist, but no fossils have been found.
This huge time gap in the fossil record hides the early evolutionary history of caecilians and has led to a decades-long debate amongst scientists over the relationships of caecilians to frogs and salamanders. Consensus on caecilian relationships could only be resolved through the discovery of caecilian fossils older than the Jurassic to fill this gap.
Tell us more about your fossil discovery.
During our fieldwork at Thunderstorm Ridge at the Petrified Forest National Park in Arizona — a fossil-rich layer in the rock unit called the Blue Mesa Member of the Upper Triassic Chinle formation — we discovered the first unmistakable caecilian fossils, and the oldest known caecilian fossils, partially filling this large gap. Named Funcusvermis gilmorei in our study, this find extends the caecilian fossil record by ~35 million years into the Triassic Period!
The site has also produced a diverse assemblage of over 60 animals ranging from freshwater sharks to dinosaurs. Several other new species discovered at this site have been recently described, and include the unusual reptile Skybalonyx scapter, and the tiny mammal relative Kataigidodon venetus.
The lower jaws of at least 70 individuals of Funcusvermis have been recovered here, making Thunderstorm Ridge the most abundant fossil caecilian-producing bonebed ever discovered. Seeing the first jaw under the microscope, with its distinctive double row of teeth, sent chills down my back. We immediately knew it was a caecilian, the oldest caecilian fossil ever found — a once-in-a-lifetime discovery!
What a name! What was the inspiration?
The full name of the new species is Funcusvermis gilmorei. The genus name “Funcusvermis” was inspired by the 1972 song “Funky Worm” from the album Pleasure by the Ohio Players; a favorite song that was often played while we were all excavating fossils. “Funcus” is derived from the Latinized form of the English work funky (for the upbeat, rhythmic form of dance music), and the “vermis” is derived from the Latin word for worm. The band has approved this usage.
The species name honors the Academy’s Collections Manager, Ned Gilmore. When we discovered Funcusvermis I wanted to name the species after Ned because I doubt I would have followed this exact career path (which led to the discovery of Funcusvermis) if it weren’t for Ned’s mentorship back in the day.
I visited the Academy frequently while I was a child — many, many fond memories of seeing the exhibits. My parents also took my sister Hannah and I to your museum outreach events. It was at one of these that I first remember meeting Ned and Ted. Later on in high school, I became involved with the Delaware Valley Paleontological Society, which has its monthly meetings at ANS, and got really into searching for Triassic and Cretaceous fossils in the Philadelphia area. As part of graduating, I had to find an internship to do for the last month of my senior year. I ended up volunteering that summer at the Academy helping Ned catalogue and curate herpetology wet specimens. I got to see a ton of amazing and inspirational specimens, both fossils and living animals like frogs, salamanders and lizards.
Importantly, Ned mentored me while I was searching for fossils all over the PA/NJ area, and he really helped me develop my first understandings of geology, evolution and herpetology. I went on to apply these skills I first learned with Ned during my undergraduate research at Petrified Forest National Park, and then my PhD work today.
Ned was someone who always got really excited and enthusiastic about weird and obscure animals, and especially amphibians like frogs, salamanders and caecilians, and I think that a fossil caecilian is a very appropriate animal to name after him!