Spinosaurid Dinosaurs

Two new Early Cretaceous specimens from the Wessex Formation of the Isle of Wight, UK, represent distinct and novel genera and species of spinosaurids: Ceratosuchops inferodios and Riparovenator milnerae, according to a team of paleontologists led by the University of Southampton.
Artist’s impressions of Ceratosuchops inferodios (foreground) and Riparovenator milnerae (background). Image credit: Anthony Hutchings.
Spinosaurids are members of Spinosauridae, a family of predatory theropod dinosaurs that includes the giant Spinosaurus.
These dinosaurs are known from the Early to Mid Cretaceous of Africa, Europe, South America and Asia.
Spinosaurids are among the most distinctive and yet poorly-known of large-bodied theropod dinosaurs.
They are characterized by an elongate, laterally compressed snout, sub-conical dentition and, in a subset of species, a long neural spine sail.
Their unusual skull morphology is atypical of non-avian theropod dinosaurs, and multiple lines of evidence point to an ability to exploit semi-aquatic niches.
The newly-identified spinosaurids, Ceratosuchops inferodios and Riparovenator milnerae, lived during the Early Cretaceous epoch, some 125 million years ago.
Their fragmentary and incomplete remains were discovered at Chilton Chine on the Isle of Wight’s southwest coast by fossil collectors.
The only spinosaurid skeleton previously unearthed in the UK belonged to Baryonyx, which was initially discovered in 1983.
“We found the skulls of Ceratosuchops inferodios and Riparovenator milnerae to differ not only from Baryonyx, but also one another, suggesting the UK housed a greater diversity of spinosaurids than previously thought,” said Chris Barker, a Ph.D. student at the University of Southampton.
“It might sound odd to have two similar and closely related carnivores in an ecosystem, but this is actually very common for both dinosaurs and numerous living ecosystems,” said Dr. David Hone, a paleontologist at Queen Mary University of London.
Although the skeletons of Ceratosuchops inferodios and Riparovenator milnerae are incomplete, the researchers estimate that both species measured around 9 m (30 feet) in length, snapping up prey with their meter-long skulls.
“With a series of low horns and bumps ornamenting the brow region the name of Ceratosuchops inferodios also refers to the predator’s likely hunting style, which would be similar to that of a heron,” they said.
“Herons famously catch aquatic prey around the margins of waterways but their diet is far more flexible than is generally appreciated, and can include terrestrial prey too.”
According to the study, spinosaurids might have first evolved in Europe, before dispersing into Asia, Africa and South America.
“A palaeogeographic reconstruction suggests a European origin for Spinosauridae, with at least two dispersal events into Africa,” the authors said.
The study was published in the journal Scientific Reports.
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C.T. Barker et al. 2021. New spinosaurids from the Wessex Formation (Early Cretaceous, UK) and the European origins of Spinosauridae. Sci Rep 11, 19340; doi: 10.1038/s41598-021-97870-8

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