included Moroccan pterosaurs in 2018, and found Phosphatodraco to be an azhdarchid, and the sister taxon of Aralazhdarcho from Kazakhstan. A 2021 analysis by Rodrigo and colleagues also found these two genera to be sister taxa, joined in a clade by Eurazhdarcho from Romania. This clade was supported by one clear synapomorphy (a distinct, ancestrally shared feature), that the side margin of the mid-cervical vertebrae is straight when viewed from above and below, with almost parallel sides. These researchers noted that previous studies had defined Azhdarchidae as a node-based clade with Azhdarcho and Quetzalcoatlus as internal specifiers, but cautioned that in their new phylogeny, Phosphatodraco, Zhejiangopterus, and Eurazhdarcho would fall outside the group. They found this undesirable, as those genera had otherwise consistently been considered azhdarchids, and that for stability's sake, Phosphatodraco should be added as a third internal specifier for the group, since this would result in all these taxa being included. In 2021 paleontologist Brian Andres and colleagues also found Phosphatodraco and Aralazhdarcho to be sister taxa, supported by the reduction of pneumatic foramina on the side of the neural canal. This clade was recovered as part of the azhdarchid subclade Quetzalcoatlinae. The cladogram below shows the placement of Phosphatodraco within Azhdarchiformes according to Andres and colleagues, 2021: Paleobiology Feeding and ecological niche In 2008 Witton and Naish pointed out that although azhdarchids have historically been considered to have been scavengers, probers of sediment, swimmers, waders, aerial predators, or stork-like generalists, most researchers until that point had considered them to have been skim-feeders living in coastal settings, which fed by trawling their lower jaws through water while flying and catching prey from the surface (like skimmers and some terns). In general, pterosaurs have historically been considered marine piscivores (fish-eaters), and despite their unusual anatomy, azhdarchids have been assumed to have occupied the same ecological niche. Witton and Naish noted that evidence for this mode of feeding lacked support from azhdarchid anatomy and functional morphology; they lacked cranial features such as sideways compressed lower jaws and the shock-absorbing adaptations required, and their jaws instead appear to have been almost triangular in cross-section, unlike those of skim-feeders and probers. Witton and Naish instead stated that azhdarchids probably inhabited inland environments, based on the taphonomic contexts their fossils have been found in (more than half the fossils surveyed were from for example fluvial or alluvial deposits, and most of the marine