Fossil slab captures pterosaur landing

A 150-million-year-old limestone slab in Crayssac, France, preserves a rare record of a pterosaur landing, revealing a sequence of movements that had never been documented before. This discovery, made in 2009, was published in the Proceedings of the Royal Society B by a team led by Jean-Michel Mazin.

Unique sequence of movements

The track, known as CR01.02, shows a pterosaur making initial contact with the ground using only its hind legs, then pausing on all fours before resuming walking. This pattern closely matches the expected behavior of an animal landing from flight, rather than moving through water.

Significance of the site

The Crayssac site, identified in 1987 by amateur paleontologist Gérard Lafaurie, contains between 10,000 and 15,000 imprints, representing up to 95 percent of all known Jurassic pterosaur traces worldwide. This extraordinary concentration of fossils has made the area a key location for studying pterosaur behavior.

Protection of the site

Crayssac was classified as a National Natural Reserve in 2011 and protected under a dedicated building to preserve its delicate fossils. The limestone layer, only 1.2 meters thick, holds an exceptional density of imprints, including fine details like the movement of the hind limbs.

Scientific debate and resolution

Initially, some scientists, like David Unwin, suggested the marks could be from swimming rather than landing. However, the lack of any trace before the first contact and the precise sequence of movements strongly support the landing hypothesis, as explained by Kevin Padian, co-author of the 2009 study.

Broader implications

Recent research, including a study in Current Biology, highlights how such fossil imprints help understand pterosaur evolution. Crayssac’s landing track fits into the larger story of how these flying reptiles gradually adapted to life on the ground, rather than remaining exclusively airborne.