Exquisitely preserved specimen may overturn ideas about spiny creature’s home
Beat Scheffold/Palaeontological Institute and Museum/University of Zurich, Switzerland
A round belly, stubby feet and a tapering tail made one armored reptile a lousy swimmer. Despite earlier reports, Eusaurosphargis dalsassoi might not have swum at all, scientists now say.
E. dalsassoi was first identified in 2003. Fossils were found near Monte San Giorgio at the Swiss-Italian border alongside the remains of marine reptiles and fish that lived roughly 240 million years ago. That association led scientists to conclude the creature was aquatic. But a complete skeleton of E. dalsassoi unearthed in 2002 in the Swiss Alps and recently assembled contradicts that idea.
At just under 20 centimeters long, the fossil, probably of a youngster, shows that E. dalsassoi widened at the stomach and slithered forward with stiff elbow and knee joints and spadelike claws. That’s not a swimmer’s build, paleontologist Torsten Scheyer of the University of Zurich and colleagues report June 30 in Scientific Reports.
Armed with rows of small spikes along its back and spear-shaped plates framing its head, sides and tail, the animal resembled today’s girdled lizards. The researchers speculate that this particular E. dalsassoi died on a beach and then got washed into the ocean.
T. M. Scheyer et al. A new, exceptionally preserved juvenile specimen of Eusaurosphargis dalsassoi (Diapsida) and implications for Mesozoic marine diapsid phylogeny. Scientific Reports. Published online June 30, 2016. doi:10.1038/s41598-017-04514-x.
H. Thompson. Sea scorpions slashed victims with swordlike tails. Science News, Vol. 191, June 10, 2017, p. 5.