Revision of Camarillasaurus moves Monolophosaurus to the spinosaurs

According to Wikipedia – Monolophosaurus
“Monolophosaurus was originally termed a “megalosaur” and has often since been suggested to be an allosauroid. Cau (2024) recovered Monolophosaurus as a basal member of Allosauroidea.”

Cau’s 2024 study confirmed an earlier nesting in the large reptile tree (LRT, 2337 taxa. subset Fig 1) that also nested Monolophosaurus basal to Allosaurus and kin.

“In 2006, Thomas Carr suggested that Guanlong, another theropod with a large, thin, and fenestrated midline crest and from the same formation, was in fact a subadult individual of Monolophosaurus. Usually Guanlong had been considered a proceratosaurid tyrannosauroid, but Carr had performed an analysis in which both specimens clustered and were allosauroids.”

This is not confirmed by the LRT, which separates Guanlong from Monolophosaurus (Fig 1).

Wikipedia – Guanlong reports,
“Guanlong is a genus of extinct proceratosaurid tyrannosauroid dinosaur from the Late Jurassic of China.”

This is not confirmed by the LRT, which nests Guanlong with spinosaurs (Fig 1) and Proceratosaurus with little Scipionyx basal to the clades shown in figure 1.

Figure 1. Subset of the LRT focusing on spinosaurs and their relatives. ” data-image-caption=”

Figure 1. Subset of the LRT focusing on spinosaurs and their relatives.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/09/spinosaur-clade588.jpg?w=248″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/09/spinosaur-clade588.jpg?w=584″ class=”size-full wp-image-94623″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/09/spinosaur-clade588.jpg” alt=”Figure 1. Subset of the LRT focusing on spinosaurs and their relatives.” width=”584″ height=”706″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/09/spinosaur-clade588.jpg?w=584&h=706 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/09/spinosaur-clade588.jpg?w=124&h=150 124w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/09/spinosaur-clade588.jpg?w=248&h=300 248w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/09/spinosaur-clade588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 1. Subset of the LRT focusing on spinosaurs and their relatives.

Rauhut et al 2025 reported,
“A monophyletic Spinosauridae is found. This clade includes the poorly known Magnosaurus as the earliest branching member, followed by Monolophosaurus, which was found in a similar position in the equally weighted parsimony analysis of Schade et al. (2023). Given that the phylogenetic definition of Spinosauridae as currently employed (all theropods that are more closely related to Spinosaurus aegyptiacus than to either Megalosaurus bucklandii or Allosaurus fragilis; Rauhut and Pol 2019) is stem-based, these taxa would have to be regarded as a member of the Spinosauridae under this topology.”

By contrast, in the LRT Dilong, Guanlong, and Xiongguanllong nest basal to spinosaurs, while Monolophosaurus nests basal to the Allosaurus clade, as noted above (Fig 1).

Unfortunately, Dilong, Guanlong, and Xiongguanlong are not mentioned in the Rauhut et al text on spinosaurs, nor do these taxa appear in the authors’ cladograms.

So its taxon exclusion time again. The LRT minimizes taxon exclusion by including so many taxa. Too many taxa is better than too few.

References
Carr T 2006. Is Guanlong a tyrannosauroid or a subadult Monolophosaurus?. Journal of Vertebrate Paleontology. 26: 48A. doi:10.1080/02724634.2006.10010069
Rauhut OWM, Canudo JI and Castanera D 2025. Revision of the theropod dinosaur Camarillasaurus cirugedae from the Early Cretaceous (Barremian) of Teruel province, Spain. Palaeontologia Electronica, 28(3):a40.  https://doi.org/10.26879/1543
palaeo-electronica.org/content/2025/5627-revision-of-early-cretaceous-theropod-dinosaur

wiki/Monolophosaurus
wiki/Spinosauridae