Ancient Shark Species Resembling Two Animals Discovered in Mexico

In the Vallecillo limestone quarry in Mexico, a peculiar fossil has baffled paleontologists, failing to fit neatly into any previously known shark group. This new species, named Aquilolamna milarcae, has been found to possess combined characteristics of two distinct marine animal groups. The fossil was first discovered by quarry workers in 2012 and was carefully excavated by local paleontologists before being scientifically described in the journal Science by a research team from the National Centre for Scientific Research (CNRS) in France. Aquilolamna milarcae is estimated to have lived during the mid-Cretaceous period, approximately 93 million years ago, predating the Tyrannosaurus rex. During that era, global sea levels were much higher than today due to minimal polar ice caps, dividing the North American continent into two large landmasses separated by a vast seaway. Vallecillo, now a semi-arid plain, was once part of the seabed far from the coastline. The creature had pectoral fins spanning nearly 1.9 meters, while its total body length from head to tail was only about 1.6 meters, making its body wider than it was long. Its broad head and elongated pectoral fins gave the front part of its body a striking resemblance to a manta ray. However, the posterior part of its body tells a different story. Aquilolamna milarcae's tail fin is distinctively shark-like, and based on this vertebral structure and tail fin, the research team has classified the species within the order Lamniformes, a group that also includes plankton-eating sharks and mako sharks.