Dinosaur fossil with 'totally weird' spikes in skeleton stuns experts

[muriel_volestrangler]

Fossil hunters have unearthed remnants of the oldest – and probably weirdest – ankylosaur known so far from a site in the Middle Atlas mountains in Morocco.

The remains of the heavily armoured animal are extraordinary in being the first to have defensive spikes that are fused to the skeleton, a feature researchers say is unprecedented in the animal kingdom.
...
The discovery was so unusual that scientists wondered whether the fossil might be a fake, but further inspection using a CT scanner found no signs that it had been constructed or tampered with.

The fossil dates to the middle Jurassic, about 168m years ago, suggesting the animal was one of the earlier ankylosaurs to roam the Earth. Beyond ranking as the oldest ankylosaur fossil known so far, it is also the first to be found in Africa.

https://www.theguardian.com/science/2021/sep/23/dinosaur-fossil-with-totally-weird-spikes-in-skeleton-stuns-experts

Bizarre dermal armour suggests the first African ankylosaur

Ankylosauria is a diverse clade of armoured dinosaurs whose members were important constituents of many Cretaceous faunas. Phylogenetic analyses imply that the clade diverged from its sister taxon, Stegosauria, during the late Early Jurassic, but the fossil records of both clades are sparse until the Late Jurassic (~150 million years ago). Moreover, Ankylosauria is almost entirely restricted to former Laurasian continents, with only a single valid Gondwanan taxon. Spicomellus afer gen. et sp. nov. appears to represent the earliest-known ankylosaur and the first to be named from Africa, from the Middle Jurassic (Bathonian– Callovian) of Morocco, filling an important gap in dinosaur evolution. The specimen consists of a rib with spiked dermal armour fused to its dorsal surface, an unprecedented morphology among extinct and extant vertebrates. The specimen reveals an unrealized morphological diversity of armoured dinosaurs during their early evolution, and implies the presence of an important but undiscovered Gondwanan fossil record.

Ankylosauria is a diverse clade of armoured herbivorous dinosaurs characterized by the possession of a diversity of osteoderms located on the skull, dorsal surface of the body and tail1,2. Ankylosaurs diverged from their sister-taxon, Stegosauria, in the late Early or early Middle Jurassic, but their fossil record at this time is extremely sparse2–4. Indeed, the only valid Middle Jurassic ankylosaur is Sarcolestes leedsi, represented by a partial lower jaw5. Ankylosauria increased in diversity in the Early Cretaceous, becoming important constituents of Late Cretaceous ecosystems, and went extinct along with other non-avian dinosaurs at the end-Cretaceous mass extinction1–4. Ankylosaurs are well-known on the former Laurasian continents, but their fossil record in Gondwana is highly fragmentary with only a single valid taxon being recognized6, although tantalizing fragmentary material suggests that they were more widespread. Here we describe a new specimen that we interpret as an ankylosaur from the Middle Jurassic (Bathonian/Callovian) of the Middle Atlas Mountains of Morocco – the first from Africa. The specimen fills a gap in the fossil record of Ankylosauria, suggesting that shortly after their evolution, ankylosaurs had attained a global distribution, and indicates an important but as yet undiscovered armoured dinosaur fossil record in the Jurassic of Gondwana.

https://www.nature.com/articles/s41559-021-01553-6

[hlthe2b]

1. I can see why they would have wondered initially if they were fake. How bizarre.

What might they have been facing to cause them to evolve spikes ankylosed (fused) to the skeleton?