International researchers, including Dr. Adrienne Jochum of Senckenberg, have discovered a new species of land snail in a piece of amber approximately 99 million years old. The snail’s shell features short, bristly hairs that are arranged along its margin. In their study published in the journal Cretaceous researchthe team, led by first author Dr Jean-Michel Bichain of the Museum of Natural History and Ethnography in Colmar, France, concludes that the presence of hairs may have offered the molluscs a selective advantage in their evolution.
The fine hairs, measuring only 150 to 200 micrometers in length, have been detected on the shell of the newly discovered species Archaeocyclotus brevivillosus sp. nov. using conventional microscopy and 3D X-ray micro-computed tomography.
“This is already the sixth species of hairy-shelled Cyclophoridae, a group of tropical land snails found so far, embedded in Mesozoic amber, around 99 million years old,” says Dr. Adrienne Jochum from the Senckenberg Research Institute and the Natural History Museum Frankfurt and the Natural History Museum Bern. Dr. Jochum explains that “it is not uncommon for fossil and extant land snail shells to be adorned with ridges, hairs, nodules or folds; however, the development of such ‘decoration’ is still a complex process that does not happen without purpose.”
The hairs of snail shells are formed by the upper layer of the protein shell (periostracum). Hairy shells are known from several families of land snails, including the wood snails or the Polygyridae snails, suggesting that hairiness arose several times independently during the evolution of land snails, even in groups that were only distantly related.
“The new species, Archaeocyclotus brevivillosus, comes from a Cretaceous amber mine in Burma’s Hukawng Valley, where it was collected before 2017. The fossil snail is 26.5 millimeters long, 21 millimeters wide and 9 millimeters high. The outer margin of the shell is lined with short hairs which are clustered around the opening of the shell. Its name derives from the Latin words brevis (short or small) and villōsus (hairy or shaggy)”, explains Jochum, describing the animal.
A total of eight species of the family Cyclophoridae have been recovered from Burmese amber, and six of them exhibited spiky shells. Scientists believe this is no coincidence. They speculate that hairiness gave snails an evolutionary advantage.
“For example, the hairs could improve the ability of animals to cling better to the stems or leaves of plants, which has already been observed in modern snails. They may also have played a role in the thermal regulation of the snail by allowing tiny water droplets to adhere to the shell, thus serving as an ‘air conditioner.’ Or they may have protected the snail’s shell from corrosion by the highly acidic soil and leaf litter. the ancient rainforest floor.The hairs could also have served as camouflage or protected the snail from direct attack by stalker birds or ground predators.Finally, it cannot be excluded that the hairs provided an advantage in sexual selection,” says Jochum, summarizing the possible benefits of hairs for snails.
A 99-million-year-old snail fossilized in amber during childbirth
Jean-Michel Bichain et al, Archaeocyclotus brevivillosus sp. nov., a new cyclophorid land snail (Gastropoda: Cyclophoroidea) from mid-Cretaceous Burmese amber, Cretaceous research (2022). DOI: 10.1016/j.cretres.2022.105359
Provided by Senckenberg Research Institute and Natural History Museum
Quote: Hairy snail discovered in 99 million year old amber (2022, October 25) Retrieved October 25, 2022 from https://phys.org/news/2022-10-hairy-snail-million-year- old amber. html
This document is subject to copyright. Except for fair use for purposes of private study or research, no part may be reproduced without written permission. The content is provided for information only.
#Hairy #snail #discovered #million #year #amber