Evidence of armor in dinosaurs dates back to the Jurassic period, as demonstrated by the discovery of skin-derived osteoderms. However, past findings, limited to a rib and some mouth parts, have not provided a comprehensive understanding of these armored creatures.
Recent discoveries of Spicomellus remains have shed light on the evolution of ankylosaur armor, revealing that it became less intricate over time.
Unlike later ankylosaurs that featured smaller, solid spikes, the armor of Spicomellus boasted a back brimming with prominent, sharp spines. Each rib is believed to have produced up to six spikes, with some reaching impressive lengths, resembling lances more than defensive features.
The most notable spikes were located along its neck, where fused osteoderms formed a prominent half-collar of bone adorned with multiple elongated spikes. The researchers highlighted that no other known ankylosaur displays a similar configuration to the remarkable spines found on the cervical half-ring of Spicomellus.
In addition to its striking appearance, features on the tail vertebrae indicate that this dinosaur may have possessed a weaponized tail. The study’s authors assert that the specimen showcases extreme dermal armor modifications that are unprecedented among both extinct and modern vertebrates, setting Spicomellus apart from other armored dinosaurs.
Challenges in Classification
The distinctive traits of the Spicomellus skeleton make it challenging to classify within existing ankylosaur family trees. Researchers suggest that while some skeletal features align Spicomellus with ankylosaurs, it is likely an early offshoot of the main lineage. However, the lack of additional significant specimens from that era makes this classification tentative. There remains a possibility that Spicomellus is unrelated to other known organisms sharing a few of its unusual characteristics, a concept that remains difficult for scientists to accept.
