British scientists have identified the smallest and youngest ichthyosaurus on record, along with a surprise preserved in its stomach.
The ichthyosaur fossil, about 70 centimetres long, had the remains of a prehistoric squid in its stomach.
“It is amazing to think we know what a creature that is nearly 200 million years old ate for its last meal,” University of Manchester palaeontologist Dean Lomax says.
“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.”
Lomax was among the researchers who recently identified the largest ichthyosaur ever found, a 3.5-metre adult fossil, as a new species in the genus. That specimen contained the petrified bones of a foetus in its womb.
The latest specimen, belonging to the species Ichthyosaurus communis, is from the collection of the University of Birmingham’s Lapworth Museum of Geology in the UK. It is described in the journal Historical Biology.
Based on microfossils preserved in the rock from around the skeleton, researchers found that the animal dated from about 199–196 million years ago, the early Jurassic period.
“There are several small Ichthyosaurus specimens known but most are incomplete or poorly preserved,” Lomax says.
“This specimen is practically complete and is exceptional. It is the first newborn Ichthyosaurus communis to be found, which is surprising considering that the species was first described almost 200 years ago.”
I. communis was the earliest species from this group of seagoing reptiles to be properly recognised, in 1821. It is one of the most common early Jurassic fossil reptiles in Britain. Many examples were found by British Victorian-era palaeontologist Mary Anning, investigating Jurassic marine fossil beds in the cliffs along the English Channel at Lyme Regis in south-west England.
In 2015, Lomax described another new ichthyosaur species, which he named I. anningae in her honour.