A team of paleontologists in the UK has identified the smallest and youngest specimen of the ichthyosaur Ichthyosaurus communis on record, and found the remains of a prehistoric squid within its stomach.
Reconstruction of a newborn Ichthyosaurus communis. Image credit: Julian Kiely.
The ichthyosaur fossil has a total length of just 27.5 inches (70 cm) and is approximately 199-196 million years old (Early Jurassic epoch).
University of Manchester paleontologist Dean Lomax and colleagues identified it as a newborn Ichthyosaurus communis, based on the arrangement of bones in the skull.
“It is amazing to think we know what a creature that is nearly 200 million years old ate for its last meal,” Lomax said.
“We found many tiny hook-like structures preserved between the ribs. These are from the arms of prehistoric squid. So, we know this animal’s last meal before it died was squid.”
“This is interesting because a study by other researchers on a different type of ichthyosaur, called Stenopterygius, which is from a geologically younger age, found that the small — and therefore young — examples of that species fed exclusively on fish. This shows a difference in prey-preference in newborn ichthyosaurs.”
The skeleton of a newborn Ichthyosaurus communis. Scale bar – 10 cm. Image credit: Lomax et al, doi: 10.1080/08912963.2017.1382488.
The new specimen of Ichthyosaurus communis is from the collections of the Lapworth Museum of Geology, University of Birmingham.
“There are several small Ichthyosaurus specimens known, but most are incomplete or poorly preserved. This specimen is practically complete and is exceptional,” Lomax said.
“It is the first newborn Ichthyosaurus communis to be found, which is surprising considering that the species was first described almost 200 years ago.”
The research is published in the journal Historical Biology.
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Dean R. Lomax et al. The first known neonate Ichthyosaurus communis skeleton: a rediscovered specimen from the Lower Jurassic, UK. Historical Biology, published online October 3, 2017; doi: 10.1080/08912963.2017.1382488
