A new genus and species of mosasaur has been identified from a 1-m- (3.3-foot-) long skull and isolated bones found in a phosphate mine in Morocco.
Life reconstruction of Gavialimimus almaghribensis hunting a school of teleosts. Image credit: Tatsuya Shinmura.
The new mosasaur species swam in the oceans between 72 and 66 million years ago (Cretaceous period).
Scientifically named Gavialimimus almaghribensis, it had a long, narrow snout and interlocking teeth — similar to gharials, relatives of crocodiles and alligators.
“This discovery adds a layer of clarity to a diverse picture seemingly overcrowded with mega-predators all competing for food, space and resources,” said lead author Catie Strong, a student in the Department of Biological Sciences at the University of Alberta.
“Its long snout reflects that this mosasaur was likely adapted to a specific form of predation, or niche partitioning, within this larger ecosystem.”
There is evidence that each mosasaur species shows adaptations for different prey items or styles of predation.
The fossilized skull of Gavialimimus almaghribensis. Image credit: Catie Strong.
“For some species, these adaptations can be very prominent, such as the extremely long snout and the interlocking teeth in Gavialimimus almaghribensis, which we hypothesized as helping it to catch rapidly moving prey,” Strong said.
“Another distinctive species would be Globidens simplex, which has stout, globular teeth adapted for crushing hard prey like shelled animals.”
“Not all of the adaptations in these dozen or so species are this dramatic, and in some cases there may have been some overlap in prey items, but overall there is evidence that there’s been diversification of these species into different niches,” she said.
Alternatively, the main contrasting hypothesis would be a scenario of more direct competition among species.
“Given the anatomical differences among these mosasaurs, though, the idea of niche partitioning seems more consistent with the anatomy of these various species,” Strong said.
“This does help give another dimension to that diversity and shows how all of these animals living at the same time in the same place were able to branch off and take their own paths through evolution to be able to coexist like that.”
The discovery of Gavialimimus almaghribensis is described in a paper in the Journal of Systematic Palaeontology.
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Catherine R.C. Strong et al. A new species of longirostrine plioplatecarpine mosasaur (Squamata: Mosasauridae) from the Late Cretaceous of Morocco, with a re-evaluation of the problematic taxon ‘Platecarpus’ ptychodon. Journal of Systematic Palaeontology, published online September 28, 2020; doi: 10.1080/14772019.2020.1818322
