Pelvic and femoral anatomy of the Allodaposuchidae (Crocodyliformes, Eusuchia) from the Late Cretaceous of Lo Hueco (Cuenca, Spain)

Purpose The fossil record of postcranial remains assigned to Allodaposuchidae is currently sparse. However, the Late Cretaceous paleontological site of Lo Hueco (Cuenca, Spain), from where two new taxa of allodaposuchid have been described, has yielded numerous postcranial remains assignable to this clade. Among them, the large amount of pelvic and femoral material is notable, providing the opportunity to study these allodaposuchid elements and assess their morphological similarity with other eusuchian remains. Methods The comparison with extant crocodylians was accomplished using traditional morphometric techniques, whereas the comparison with other fossils and establishment of morphotypes was done using morphological criteria. Results The results of the cluster and principal components analyses show morphological differences between extant crocodylians and allodaposuchids from Lo Hueco, allowing the segregation of these lineages. The similarities found between the pelvic and femoral remains from Lo Hueco, and those referred to Allodaposuchus precedens and other putative allodaposuchids from the Iberian Peninsula, allows referral of these remains to allodaposuchids. The differences found among the femoral and pelvic remains of Lo Hueco enables us to recognize two morphotypes per each element. Conclusions This study allows a better understanding of allodaposuchid postcranial elements that were previously poorly known. The ilia, ischia and femora from Lo Hueco allodaposuchids are distinct from those of other crocodylian lineages. Finally, the fact that there are two morphotypes per each element at Lo Hueco is congruent with the presence of two different allodaposuchids at the site.