The Paravertebra

Photo by Cas Liber

The species in question this week, Minmi paravertebra, has an interesting specific epithet that describes a specialized adaptation of the animal. Minmi, as we know, was one of the most basal, and therefore first, ankylosaurs. As expected, then, it must have had adaptations that set it apart from earlier ancestors as well as primitive adaptations that would be present, continued or more derived, in its descendants. One such trait, the one after which its specific epithet is named, is the armored nature of its vertebral column. Ossified dermal scutes as well as bony protrusions of armor have been well documented in specimens of Minmi but perhaps the most interesting armor is that found along the vertebral column. Horizontal plates of bone run along the lateral edges of the vertebrae the entire length of the column. These plates also give Minmi a parted down the middle look; scutes of armor are absent above the vertebrae and a negative space exists along the vertebral column.

Some models and illustrations show Minmi with relatively large shoulder spines protruding outward, though there is minimal evidence at best for the existence of such material. The majority of Minmi is covered in small protrusions of armor, save the negative space along the vertebral column. The head and neck are covered as well in most representations and there appears to be evidence for these coverings in the fossilized specimens.