Three-dimensionally preserved eggs were reported in 2014. Comparisons between the scleral rings of "Pterodaustro" and modern birds and reptiles suggest that it may have been nocturnal and similar in activity patterns to modern anseriform birds that feed at night. Because of its long torso and neck and comparatively short legs, "Pterodaustro" was unique among pterosaurs in having difficulties to launch. Even with the pterosaurian quadrupedal launching mechanism, it would have required frantic and fairly-low angled take-offs possible only in open areas, much like modern geese and swans. Bonaparte in 1970 assigned "Pterodaustro" to the Pterodactylidae; in 1971 to a Pterodaustriidae. However, from 1996 cladistic studies by Alexander Kellner and David Unwin have shown a position in the Ctenochasmatidae, together with other filter feeders. Cladogram following Andres, Clark & Xu, 2014. In 2018, Longrich, Martill, and Andres recovered a significantly different set of relationships for early pterodactyloids in their own analysis, as shown below using the earliest available definitions for each clade name.