Two fragments of a tiny crocodile skull found three months apart by different private collectors fit together perfectly to make a complete skull.
The species was named Koumpiodontosuchus aprosdokiti, which means the "unexpected button toothed crocodile," by University of Portsmouth palaeontologist Dr Steve Sweetman.
The back half of the tiny skull was found on a beach near Sandown on the Isle of Wight by Diane Trevarthen, while on a fossil-hunting holiday with her family.
Three months later Austin and Finley Nathan, also fossil-hunting while holidaying on the island, found another tiny fragment of skull, this time a snout.
More From This Section
The museum re-examined the earlier specimen and found that it fitted perfectly together with the snout.
"Both parts must therefore have been found very soon after they were released from the mud and debris originally laid down on a dinosaur trampled river floodplain around 126 million years ago," Sweetman said.
On first inspection Sweetman thought the skull belonged to a crocodile known as Bernissartia fagesii known from skeletons of a similar age discovered first in Belgium and later in Spain.
"The location of the hole in the mouth, where the airway from the nose opens, was surrounded by bones at the very back of the palate.
"This tells us that the discovery is not only a new species but also a new genus of ancient croc closely related to, but subtly different to those alive today," Sweetman said.
The finding was published in the journal Acta Palaeontologica Polonica.