Secrets of a scavenger

An ancient fragment of a skull from a 125-million-year-old flying reptile has unlocked secrets to how the creature scavenged for food, an expert said.

Istiodactylus is an exceptional creature possessing unusual, interlocking ‘cookie cutter’ teeth with razor edges

Mark Witton, a palaeontologist from the University of Portsmouth, has re-examined the fragment which has been housed in the Natural History Museum in London for more than a century.

He believes it shows that the pterosaur was a scavenging, vulture-like creature which lived off the carcasses of dinosaurs.

His study, published in the international Public Library of Science journal, PLoS ONE, suggests that the dimensions of the Istiodactylus’ skull can be reconstructed more accurately providing new insights into its feeding habits.

He said: “Istiodactylus is an exceptional creature possessing unusual, interlocking ‘cookie cutter’ teeth with razor edges.

“These have suggested to some that this pterosaur was a vulture-like scavenger, but supporting evidence from the rest of the skull was lacking.

“This fragment suggests the skull was a good 20 per cent shorter than previously supposed so, instead of a very long, low skull, it appears to have had quite the opposite – very short, very wide and very tall.

“This was rather unexpected as we thought we were very familiar with its anatomy, but it seems it is far more distinctive than we previously realised.”

Dr Witton, who specialises in pterosaurs, enormous winged creatures which soared the skies when dinosaurs roamed the earth, realised the significance of the third segment during a recent visit to the museum.

The specimen, Istiodactylus latidens, consisted of a skull broken into two large pieces representing the braincase and jaw tips, but little consideration had been given to the third element that seems to bridge the gap between them.

For almost 100 years, the creature was thought to have had a very long, low skull exceeding half a metre in length but its exact proportions were never clear as only the jaw tips and braincase of the animal had been studied.

Dr Witton suggests that the third fragment reveals an unusually short and tall cranium and, combined with previous observations on the unusual teeth of this animal, he suggests that it provides an improved understanding of Istiodactylus’ diet and foraging habits.

The third fragment indicates that the creature’s cheek bones were incredibly slender – only 6mm tall in a skull around 450mm long. By contrast, other parts of the skull were very robust.

Dr Witton said: “Modern scavenging birds have similar skull constructions, possessing both strong and weak skull components.

“Feeding on dead flesh allows them almost complete control over how they feed, so they can afford to have some weaker regions along their jaws without the worry of breaking them when biting into carcasses.

“The proportionally wide, tall skull would also anchor a good set of neck muscles, indicating a strong neck which is another feature shared with vultures which use their strong necks to pull carcasses apart.

“When considered with the shearing teeth, these attributes provide good evidence of scavenging lifestyles in these animals.”

The specimen of Istiodactylus was discovered on the Isle of Wight in late 1904 and has been in the Natural History Museum’s collections since 1911.