Land snails are usually preserved as fossilized snail shells or imprints, while preservation of their soft bodies is a rarity. "Our new amber find is truly remarkable for this reason as well," explains Dr. Adrienne Jochum of the Senckenberg Research Institute and Natural History Museum Frankfurt and the Natural History Museum of the Burgergemeinde Bern, and she continues, "In a piece of Cretaceous amber from Myanmar, we discovered the body and shell of an exceptionally well-preserved female land snail shortly after the birth of her offspring, which is also preserved in the amber."
Together with colleagues from China and Germany, Jochum examined the
amber using high-resolution photography and micro-computer tomography images
and was able to reveal the snail shell, which is about 11 millimeters high, and
the "marshmallow-like" body of the mother as well as the five
newly-born young.
"The snails were apparently encased in the tree resin immediately
after birth and preserved in that position over millions of years. The mother
snail must have noticed her impending fate and is stretching her tentacles up
in a 'red alert' posture," adds Jochum.
Although live births are known in land snails, they are considered the
exception. The researchers assume that the species, newly described as
Cretatortulosa gignens, gave birth to its young alive in order to protect its
offspring from predators as long as possible in the tropical forests of the
Cretaceous.
Jochum explains, "Just like their modern relatives from the genus
Cyclophoroidea, our new discovery probably spent its life inconspicuously on
dead and rotting leaves. We assume that the young of this species—compared to
egg-laying snails—were smaller and lower in number to increase their chance of
survival."
According to the study, the fossil from an amber mine in northern
Myanmar offers unprecedented insights into the ecology and behaviour of snails
that lived 99 million years ago.
"Based on the discovery, we can not only make statements about the
morphology and paleoecology of the animals, but we now also know that
viviparous snails existed in the Cretaceous period," adds a delighted
Jochum.
The study is published in Gondwana Research.
Source: Senckenberg Research Institute and Natural History Museum
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