The remains, dinosaur feathers and mammalian hairs, belong to the Lower Cretaceous, with an age of between 105 and 110 million years , whose description and analysis have been published in the journal Scientific Reports .
The research team, made up of Sergio Álvarez Parra, Xavier Delclòs (both from the University of Barcelona), Mónica M. Solórzano Kraemer (Senckenberg Museum of Natural History in Frankfurt am Main), Luis Alcalá (Fundación Conjunto Paleontológico de Teruel-Dinópolis) and Enrique Peñalver (Geological and Mining Institute of Spain) has unraveled the origin of the two pieces found in the resin produced in an aerial environment in that period of time.
The pieces were located in two different locations: one was found years ago in the amber deposit of San Just , in the municipality of Utrillas (the dinosaur feathers), and the other in Ariño , in the excavation during the summer of 2019 with object of extracting amber in the Santa María mine. What they did not expect was to find the remains of vertebrates inserted in the amber. It is precisely this last piece that corresponds to the discovery of the oldest mammal hair in amber in the world.
Ariño amber has three mammalian hairs with their characteristic microscopic scale pattern, exceptionally well preserved thanks to amber. The parallel arrangement of the three hairs and their similar proportions allow researchers to identify it as a small tuft of a mammal.
What creatures do both remains belong to?
“The determination of both findings is very complex, but it is likely that the feather remains correspond to the extinct Enantiornithes birds, as well as other feathers in amber. As for the lock of hair, we must consider that the pattern of superficial scales is similar to that of the hair of current mammals ”, explains Sergio Álvarez, researcher at the UB and first author of the study. “Ariño was already known for his vertebrate fossils, such as the dinosaurs Proa valdearinnoensis and Europelta carbonensis, but no one thought that we could find vertebrate remains included in amber,” adds Álvarez.
How were these pieces generated?
According to scientists, both pieces have their origin in the same conservation process described as ” pull off vestiture” which is based on catching small portions of plumage or fur from a living specimen, when in contact with a mass sticky resin, either while sleeping or resting on or near a tree; remaining inactive for the necessary time so that some hardening of the resin took place and trapped the hairs or feathers. It is the key in this preservation method: it is necessary that a certain time elapses in this contact of the resin with the animal for this “clothing removal” to occur.
The two pieces of amber in this study are deposited in the Aragonese Museum of Paleontology (Fundación Conjunto Paleontológico de Teruel-Dinópolis) and both add even more value to the extensive fossil record of the province of Teruel.
Referencia: Álvarez-Parra, S et al. “Cretaceous amniote integuments recorded through a taphonomic process unique to resins”. Scientific Reports
