Inabtanin: a large Late Cretaceous pterosaur from Jordan

Inabtanin alarabia is based on a partial skeleton from Jordanian phosphate deposits. It preserves portions of the jaws and neck together with much of one wing. Researchers estimated a wingspan near five metres and used CT scans of the humerus to investigate how the wing may have borne flight loads. Those scans support a functional interpretation, not a direct observation of its flight.

Quick facts

A fossil from Jordanian phosphate deposits

The holotype was found at the Inab-6 locality near Russeifa. Its Muwaqqar Formation rocks date to the Maastrichtian near the end of the Cretaceous. The specimen combines upper and lower jaw pieces, early cervical vertebrae, a scapulocoracoid, a left humerus and much of the right wing. Several long wing bones make a size estimate possible, although the skeleton is incomplete.

The genus name draws on Arabic words associated with grapes and a dragon; alarabia refers to the Arabian Peninsula. The preserved jaws lacked teeth. They do not reveal colour, soft tissues or a specific diet. The original study recognised an azhdarchoid but did not resolve a precise family through a full phylogenetic analysis.

Wing bones and a five-metre estimate

The authors estimated a wingspan of roughly five metres from the preserved wing bones. The number is inferred from proportions: neither a complete outstretched wing nor the outline of its flight membrane survives. The study also considered the much larger Arambourgiania, whose wingspan estimate rests on different material.

CT scanning exposed a network of thin supports inside Inabtanin's humerus. Their orientation matters to resistance under load. The authors compared this structure with wing bones of living birds and suggested that Inabtanin could have relied substantially on flapping, while much larger pterosaurs might have spent more time soaring. This is an inference from anatomy, not an observation of wingbeats or a measured travel route.

What the locality does not establish

The animal was buried in marine deposits, but burial at sea does not prove that it always lived above open water. Toothlessness likewise does not identify its prey. Inabtanin preserves bones useful for flight comparisons; Huanhepterus instead offers a densely toothed snout. Their fossils answer different questions and come from different places and times.

Reading the reconstruction

The cover and shoreline scene are artistic interpretations of a living pterosaur. The fossil supports the existence of a toothless beak and large wing bones, while colouring, soft tissues and behaviour remain choices for the illustration.