The Hands and Feet of Pterosaurs: Insights into Taxonomy, Ecology, and Ichnology

<p dir="ltr">Pterosaurs, extinct reptiles of the Mesozoic (210-66 million years ago) were the first vertebrates to achieve powered flight. While their aerial abilities are well studied, their interactions with terrestrial ecosystems remain poorly understood, largely due to limited research on their hand and foot anatomy. This study provides a comprehensive quantitative assessment of autopodial morphology across Pterosauria, demonstrating that hands and feet are critical yet underutilised tools for addressing taxonomic, palaeoecological, and ichnological questions. (1) Pterosaur autopodia are revealed as valuable taxonomic tools. Historically overlooked, hand and foot morphology can resolve longstanding debates, exemplified by the Pterodactylus-complex. This case study demonstrates that Pterodactylus antiquus and Diopecephalus kochi are distinct taxa, that can be reliably differentiated by differences in autopodial anatomy. (2) Manus and pes morphology also provide insights into functional adaptations and ecological roles. These structures, directly interacting with the environment, reflect mechanical demands of varying locomotor ecologies. Using ecologically driven variation in autopodial morphology across extant amniotes as a framework, locomotor hypotheses are tested across Pterosauria. Results reveal a high degree of phalangeal disparity, comparable to extant birds and lepidosaurs. Early non-pterodactyliforms exhibit features consistent with arboreal or scansorial ecologies, while derived pterodactyliforms show increasing terrestrial adaptations from the Middle Jurassic onward. (3) Integration of autopodial and ichnological data corroborates this hypothesis. Pterosaur pes morphologies, strongly influenced by skeletal anatomy, exhibit restricted soft tissue coverage and arthral foot pad arrangements. These features enable the assignment of distinctive track morphotypes to specific trackmaking clades. Non-pterodactyloid tracks are absent, while pterodactyloid tracks dominate over 140 global localities from the Mid-Jurassic to the end-Cretaceous. Tracks are primarily associated with the most terrestrially adapted groups based on autopodial proportions: ctenochasmatoids, dsungaripterids, and neoazhdarchoids. This work highlights how the track record serves as an independent line of evidence which can be used to test anatomical hypotheses.</p>