Spinosaurus: wet? dry? or with muddy feet?

Sereno et al. [again] promote the hypothesis that,
“Two stages are clarified in the evolution of Spinosaurus[Fig 1] , which is best understood as a semiaquatic bipedal ambush piscivore that frequented the margins of coastal and inland waterways.”

Yes,
we looked at this paper earlier last May when it was ‘pre-printed.’ Sereno et al was Received: 07 May 2022, Preprinted: 26 May 2022, Accepted: 05 October 2022 and Published: 30 November 2022. Evidently it was refereed sometime between May and October. So… why did we see it before peer-review? This is the way things are nowadays.

Nowhere in the Sereno et al text
are the terms “temperature” or “regulation” (see figure 2), glossing over one hypothesis for the hyper-development of the sail back. We looked at Spinosaurus thermoregulation earlier here.

Two taxa from the Sereno et al taxon list enter
the large reptile tree (LRT, 2186 taxa, subset Fig 3) today: Baryonyx and Afrovenator, both added in an attempt to more closely replicate the Sereno et al taxon list (with more completely known taxa). Here it appears Sereno et al did not include enough taxa to understand the ancestry of spinosaurs. In their cladogram, Ceratosaurus is ancestral. In the LRT Ceratosaurus is a taxon without descendants. Adding taxa always clarifies interrelationships. And science is a moving frontier.

References
Ibrahim N, Sereno PC, Dal Sasso C, Maganuco S, Fabbri M, Martill DM, Zouhri S, Myhrvold N, Iurino DA 2014. Semiaquatic adaptations in a giant predatory dinosaur. Science. doi:10.1126/science.1258750.
Sereno PC et al (8 co-authors) 2022. Spinosaurus is not an aquatic dinosaur. eLife 2022;11:e80092. DOI: https://doi.org/10.7554/eLife.80092

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