The pelvic armor elements in the ankylosaurian material from the Upper Cretaceous
of Iharkut, Hungary are described here. Among these, a new articulated hip region
of a small bodied ankylosaur is referred here to cf. Struthiosaurus sp. It preserves,
uniquely among Late Cretaceous European ankylosaurs, an in situ pelvic armor composed
of among others four, keeled, oval to circular osteoderms lying centrally and arranged
longitudinally above the synsacral neural spines. This is the first indication of
this type of pelvic osteoderm arrangement in an ankylosaur, increasing our knowledge
on this poorly known part of the ankylosaur skeleton. Some additional pelvic osteoderms
are also described that help to reconstruct and distinguish the pelvic armor of the
two Late Cretaceous European ankylosaurs Struthiosaurus and Hungarosaurus. Both taxa
have some fused parts in the pelvic armor but most probably neither of them had a
single, fused pelvic shield as that of the Early Cretaceous Polacanthus. Interwoven
texture on the ventral surface of the osteoderms, observed in both European taxa and
known in other ankylosaurs (e.g. Polacanthus, Nodosaurus), is suggested here to be
a characteristic feature of the non-keeled, fused pelvic armor elements of Ankylosauria.
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