While the mosasaur on display at the Natural History Museum of Los Angeles County’s Dinosaur Hall is more complete, paleontology collections full of less-intact fossils can help scientists understand the history of life on earth. (photo courtesy of the Natural History Museum of Los Angeles County)

Making up the vast majority of paleontological collections, less complete fossils like jaws, teeth and ribs have made researchers wonder whether they had anything reliable to say about evolution.

Published recently in “Paleobiology,” a new study led by Hank Woolley, a graduate student-in-residence at the Natural History Museum of Los Angeles County Dinosaur Institute, finds that fragmentary fossils can contain reliable phylogenetic information, increasing the scientific value of all specimens housed in collections, not just the most complete ones.

“This is exciting, because results like ours increase the scientific value of incomplete specimens housed in museum collections, and that allows us to include more of Earth’s extinct biodiversity as we continue to piece together the past,” Woolley said.

Fossils captivate the imagination, especially the rare, remarkably complete specimens that decorate the exhibit halls of museums around the world, but behind-the-scenes museum collections are teeming with less complete fossils that often never see the public eye.

“We often only get to hear about excavations of exceptionally complete fossil animals and plants, but in the background, the majority of the collections that paleontologists make in the field is made up of incomplete and fragmentary fossils,” Woolley added. “It’s historically been hard to quantify how trustworthy these fossils are, since they’re so incomplete. What we do in our study is attempt to quantify just how reliable incomplete fossils are when we try to figure out their evolutionary relationships.”

Assessing evolutionary relationships of fossil organisms remains one of the great ongoing endeavors of paleontology and the study of fossils.

Woolley and his team wanted to test whether all of the less complete fossils filling up museum collections could help reliably answer those questions. To do so, they used more than 6,500 specimens from NHM and other major natural history collections.

First, they identified the most common partial fossils across the collections. While complete skulls are the gold standard – capturing key features that let paleontologists know how closely two species sit on the tree of life – the team found that jaws, teeth, ribs and vertebrae were the most common fossils.

Woolley and his team then used a series of sophisticated phylogenetic comparative methods, metrics and tests to show that the incomplete representations of the skeleton in the fossil record do not mislead interpretations of evolutionary relationships of lizards, snakes and their relatives.

Their study revealed that the less-complete fossils making up the bulk of paleontological collections do in fact contain reliable phylogenetic information, reinforcing the importance of natural history collections for future research.

For information, visit nhmlac.org.