| abstract
| - Besides Azhdarchidae, Spec also harbours another diverse clade of toothless pterosaurs. Pteranodonts are perhaps the most iconic clade of pterosaurs, well established in the pop cultural imaginarium, and while utilmately losing the spotlight in the HE, Spec’s pteranodonts are perhaps the most inventive and bizarre of the world’s pterosaurs. Having possibly appeared as early as the Albian – if not deeper into the Lower Cretaceous -, pteranodontians gradually replaced their cousins in the Late Cretaceous, their domain beginning right after the systematic disappearence of their cousins, the ornithocheirids. The Santonian and Campanian periods are of particular relevance as the most iconic pteranodonts, †Pteranodon logiceps, †Geosternbergia sternbergi, †Geosternbergia maysei and †Dawndraco kanzai, dominate the flying vertebrate guilds of the north american seaways. At least a thousand †Pteranodon longiceps fossils are known, and many are so well preserved that for the longest time they proposed an important role in the understanding of pterodactyloids in general. An unique lineage of pteranodonts, the bizarre, nyctosaurids, also date back to this era, though they are much less common. Pteranodont remains before and after this span of time in the Santonian-Campanian are rare and often fragmentary, but they are found on a cosmopolitian scale, with remains occuring in not only North America, but South America, Europe and Japan as well (as well as a possible australian foot), and they span all the way to the Maastrichtian, both in the form of nyctosaurid humeri as well as well as specimens assigned to Pteranodontidae. Since the late Cretaceous that pterodactyloid pterosaur diversification has been focused on two main linages. The first is Azhdarchoidea, a clade of terrestrial pterosaurs that spawned stork, hornbill, terror bird and condor like forms, which are probably Spec's most famous pterosaurs. The other one, Pteranodontia, diversified instead on aquatic environments, giving a special touch to Spec's shores that HE's lack. By the end of the Mesozoic, it seems, larger pteranodontians were in turn replaced by the smaller, more adaptable nyctosaurids; the last known non-nyctosaurid genus was Antarctoptera, a genus which included the largest known pteranodontian ever, Antarctoptera hyperion, a massive flier with a wingspan of over 10 meters, competing directly with azhdarchids in terms of size. Said giant disappeared with the Paleogene/Eocene Thermal Maximum, which disrupted oceanic environments and caused the collapse of many food chains. During the Eocene nyctosaurids did better in freshwater environments, much like HE's early frigate birds such as Limnofregata, and with the changes imposed by the Oligocene they diversified once more, albeit with new competitors, the large radiation of icthyornithes. In Spec, Pteranodontia enters the Cenozoic with a bang, diversifying in the Eocene. Here, they witness global success and diversity, being the most common pterosaur lineage of the epoch, and the main component of the “Cenozoic Pterosaur Renaissance”. Besides characteristic marine piscivores, a variety of inland forms also appear, a few like Messelosauravis having wingspans beneath 1.5 meters. Much like in earlier ornithocheiroids, a wide range of wing proportions can be seen: while all retain large wings, in many of these forms either the wing finger or the fourth metacarpal is dramatically shorter, showcasing the tendency for inland flyers to have shorter wings. In some forms, the clawed finger metacarpals are still long and connected to the wrist, which may either be an atavism or an ancestral feature, since the phylogeny of many of these pterosaurs is only now starting to be understood. Most retain the “normal” stork like beak, though some have serrations and strange jaw curvatures. Pteranodontid fossils decrease drastically in number by the Oligocene, but this appears to be an artifact of preservation rather than a genuine feature, as the diversity achieved in the Eocene still occurs well into the Miocene; Pteranodontidae itself, however, appears to have disappeared in the Oligocene. This period witnesses a dominance of nyctosaurs in particular, which become some of the most common pterosaur finds in contrast to their Maastrichtian rarity. Other pteranodontians are mostly found on terrestrial/freshwater settings, a situation that goes on the present day. Unlike azhdarchids, which witness an evident shift in diversity by the Plio-Pleistocene, it’s difficult to evaluate how pteranodont diversity coped with the glaciations, given the rarity of non-nyctosaur remains. These seem largely unaffected, and middle-Pleistocene New Zealand sites seem to imply a sudden diversity increase at least during this era.
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