Description

Inostrancevia lived in the Upper Permian in what is now northeastern Russia.

It was a large predator, of which two almost complete skeletons and other more fragmentary bone remains belonging to other individuals have been found. With a length of around 3 metres, it was one of the super predators of its time.

Why this look? Although its external appearance is not known exactly, it is ruled out that it had scales since findings in another therapsid, Estemmenosuchus, reported by P. Chudinov in 1968, show impressions of naked glandular skin on the skull, similar to that of mammals. At the same time, remains of “probable” hair have been found in fossil excrement. This would suggest that some proto-mammals could have a hair cover (P. Bajdek et al. 2016).

Other interpretations of Inostrancevia, with naked glandular skin, would be equally plausible. Endothermy in Inostrancevia, or the ability to internally self-regulate temperature, is ruled out (Araujo et al. 2022). However, some type of inertial endothermy or similar is not ruled out, as an intermediate path, which does not entail all the characteristics completely adapted to endothermy itself. We therefore speculate that hair is one of those characteristics “halfway” to endothermy. *Although the publication by Araujo et al. suggests the appearance of endothermy in mammals in the Upper Triassic, this does not mean that all the characteristics presented by endothermic mammals appeared at the same time. Inostrancevia could have been an inertial endotherm covered in hair. Its proximity to mammals makes it plausible that it had transitional characteristics towards endothermy.

Our reconstruction suggests an animal more advanced in appearance towards mammals than the traditional reptilian representation. We opted for the appearance of a nocturnal animal (vertical pupil detail), as some studies suggest they could have been (Angielczyk KD, Schmitz L. 2014).

Atention: As a paleoartistic reconstruction, it is based on current evidence and hypotheses. Despite this, this information is not sufficiently abundant and precise to know all the details of its appearance. The coloration, for example, is totally unknown and artistically it has been given a spotted pattern, which would disguise its silhouette in its habitat. Its skin and/or hair, if it exists, is also unknown.

Bibliographies consulted: Prevoslavlev, P. A. (1927). “Gorgonopsidae from the North Dvinsky excavations of V. P. Amalitsky.” Kammerer, Christian F.; Viglietti, Pia A.; Butler, Elize; Botha, Jennifer (2023-05). «Rapid turnover of top predators in African terrestrial faunas around the Permian-Triassic mass extinction» Angielczyk KD, Schmitz L. (2014) «Nocturnality in synapsids predates the origin of mammals by over 100 million years »