Due to their hollow bones with thin wals, pterosaur bones have quite some difficulty in not being destroyed. As such, the bulk of pterosaur specimens we have that do not come from lagerstattën are highly fragmentary; this pretty much helps with the notion that they didn’t decline, but it obviously has the unfortunate side effect of creating massive gaps in our understanding of these flying sauropsids.
One of the most iconic examples of the mysticism of pterosaur fragmentary remains is the often mentioned, but rarely explored Cretaceous pterodactyloid Lonchodectes. The original specimen, known as BMNH 39410, was discovered in a chalk formation in England, dating to the Turonian (making this one of the youngest known non-azhdarchid/pteranodontian pterosaurs). Originally identified as Pterodactylus compressirostris by Richard Owen in 1851, it was transfered to Ornithocheirus by Harry Govier Seeley roughly two decades later, before finally being recognised as it’s own genus by Reginald Walter Hooley in 1914 (who bizarrely also attributed the specimen as Ornithocheirus‘ holotype).
Subsequently, two other species, L. giganteus and L. daviesii, were also found, the first known from Cenomanian sediments while the latter dates all the way to the Albian, suggesting that this genus existed on this planet for a period of roughly 20 million years. Several other species formerly from Ornithocheirus and Pterodactylus were also added: L. saggitirostris, from the Hauterivian of Sussex (extending the temporal range to 39 million years), L. platystomus from the Aptian/Albian of Liaoning, and L. machaerorhynchus/microdon from the Albian deposits in the Cambridge Greensand.
Of these, only the last is considered dubious, as Alexander O. Averianov lumped it into Ornithostoma, another mysterious pterodactyloid (considered by Alexander to be an azhdarchoid, possibly related to tapejarids), though this is not considered to be an accurate statement.
Other possible lonchodectid remains have been reported from the Maastrichtian of India and Ross Island, though I haven’t checked the sources, and they might represent ornithocheirids instead. The mysterious australian pterosaur Mythunga has also been considered a lonchodectid in at least some sources.
What exactly is Lonchodectes?
Since it’s discovery as an independent genus, Lonchodectes has been consistently ping-ponged between Ornithocheiroidea and Azhdarchoidea. The latter is universally no longer considered to be a correct assertion, even more so due to the presence of teeth in Lonchodectes (Azhdarchoidea is notorious for it’s toothless taxa, after all). To my knowledge, an identity as an ornithocheiroid is also not taken seriously in most circles.
Recently, it seems fashionable to place lonchodectids within Ctenochasmatoidea, which would make them related to Pterodactylus after all. If so, Lonchodectes is among the youngest known ctenochasmatoids to exist.
The remains are far too fragmentary to attribute them any sort of lifestyle, but considering both ctenochasmatoids and non-euornithocheiroid ornithocheiroids generally fed on the ground or swimming, a stork-like lifestyle would make sense.