Strong explained there is evidence that each species of the giant marine lizard shows adaptations for different prey items or styles of predation.
“For some species, these adaptations can be very prominent, such as the extremely long snout and the interlocking teeth in Gavialimimus, which we hypothesized as helping it to catch rapidly moving prey,” she said.
She added another distinctive species would be Globidens simplex—described last year by the Caldwell lab—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,” Strong noted.
Alternatively, the main contrasting hypothesis would be a scenario of more direct competition among species. Strong said given the anatomical differences among these mosasaurs, though, the idea of niche partitioning seems more consistent with the anatomy of these various species.
“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,” she said.
The remains of the G. almaghribensis included a meter-long skull and some isolated bones. There was nothing to explain the cause of death of the specimen, which was uncovered in a phosphate mine in Morocco that is rich in fossils.
“Morocco is an incredibly good place to find fossils, especially in these phosphate mines,” Strong said. “Those phosphates themselves reflect sediments that would have been deposited in marine environments, so there are a lot of mosasaurs there.”
Reference: “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” by Catherine R. C. Strong, Michael W. Caldwell, Takuya Konishi and Alessandro Palci, 28 September 2020, Journal of Systematic Palaeontology.