MOROCCO — A newly unearthed fossil of Spicomellus afer has upended long-standing theories about the evolution of ankylosaurs, the heavily armored, plant-eating dinosaurs best known from Late Cretaceous North America and Asia.
In a study published in Nature on September 2, 2025, researchers from the Natural History Museum in London and Université Sidi Mohamed Ben Abdellah (USMBA) in Morocco revealed that Spicomellus, long known only from a single rib, is indeed an ankylosaur—and the earliest known member of the group, as well as the first ever discovered in Africa.
“The new specimen reveals extreme dermal armour modifications unlike those of any other vertebrate, extinct or extant,” wrote authors Thomas J. Raven, Paul M. Barrett, Claire B. Joyce, and Susannah C.R. Maidment. These include an “elaborate cervical half-ring” with “extremely long spikes,” fused armor on the ribs, and “a sacral shield bearing small and large spikes…arranged in a grid pattern.” One shoulder spike alone measured 87 cm in length.
But most significantly, the fossil contains “handle vertebrae”—a distinct structure previously believed to appear only in the Early Cretaceous—that anchor a tail weapon, comparable to the iconic tail clubs of Ankylosaurus.
According to the study, “The presence of handle vertebrae closely similar to those of Cretaceous ankylosaurids in the Middle Jurassic presents a fundamental challenge to this conventional understanding.”
The authors suggest these extravagant features were likely used for display and sexual selection, not just defense: “The ornate, complex and baroque armour of Spicomellus suggests that, early in their history, ankylosaur armour was under strong sexual selection and that it evolved initially primarily for display, rather than defense.”
The discovery, they conclude, “overturns several long-standing hypotheses about ankylosaur evolution,” indicating that tail weapons emerged 30 million years earlier than previously thought and were more diverse than once believed.
