Paleontologists have discovered a new giant species of Mosasaurus, named Pluridence Imeraki, derived from Late Cretaceous phosphate deposits in Morocco. This slender-jawed mosasaur may have reached over 9 m (29.5 ft) in length, making it a significant addition to the mosasaur family.
Pluridence Imeraki holotype, enlarged view of the dentary. Scale bar – 10 cm. Image credit: Nicholas R. Longrich & Nour-Eddine Jalil, doi: 10.3390/d18030159.” width=”580″ height=”281″ srcset=”https://cdn.sci.news/images/2026/03/image_14606_1-Pluridens-imelaki.jpg 580w, https://cdn.sci.news/images/2026/03/image_14606_1-Pluridens-imelaki-300×145.jpg 300w” sizes=”(max-width: 580px) 100vw, 580px”/>
Pluridence Imeraki holotype, enlarged view of the tooth. Scale bar – 10 cm. Image credit: Nicholas R. Longrich & Nour-Eddine Jalil, doi: 10.3390/d18030159.
Pluridence Imeraki existed in the ocean during the late Maastrichtian period of the Cretaceous, roughly 66 to 67 million years ago.
This species is classified under the Halisauridae subfamily, which typically includes smaller mosasaurs. Early members ranged from approximately 4 to 5 m (13 to 16.4 ft) long, such as Halisaurus, which could grow up to about 7.5 m (24.6 ft) in closely related species like Pluridence Serpentis.
At over 9 meters long, Pluridence Imeraki rivals the largest predatory mosasaurs from the region.
Dr. Nicholas Longrich from the University of Bath and Dr. Nour Eddin Jalil from the National Museum of Natural History in Paris remarked, “The Late Cretaceous saw a significant expansion of mosasaurs, a specialized group of large marine predators that dominated the oceans during the final 25 million years of this period in Marrakech.”
“Morocco’s late Maastrichtian Phosphate Formation is home to the most diverse mosasaur assemblage known, featuring what could be the richest marine reptilian fauna globally.”
“In recent years, numerous new mosasaur species have been identified, with over 16 species reported so far.”
“The four primary subfamilies of mosasauridae represented in these phosphates include mosasauridae, plioplatecarpini, tylosauridae, and halisauridae, along with basal mosasauridae like Pachybalanus.”
“While mosasaurids account for most of the species diversity, halisaurids thrived in phosphate-rich areas and were prevalent across Africa during the Cretaceous.”
Pluridence Imeraki, Pluridence Serpentis, and Halisaurus aramburgi from the latest Maastrichtian phosphates in Morocco. Scale bar – 1 m. Image credit: Nicholas R. Longrich & Nour-Eddine Jalil, doi: 10.3390/d18030159.” width=”580″ height=”323″ srcset=”https://cdn.sci.news/images/2026/03/image_14606_2-Pluridens-imelaki.jpg 580w, https://cdn.sci.news/images/2026/03/image_14606_2-Pluridens-imelaki-300×167.jpg 300w, https://cdn.sci.news/images/2026/03/image_14606_2-Pluridens-imelaki-316×176.jpg 316w, https://cdn.sci.news/images/2026/03/image_14606_2-Pluridens-imelaki-195×110.jpg 195w” sizes=”(max-width: 580px) 100vw, 580px”/>Relative sizes of Pluridence Imeraki, Pluridence Serpentis, and Halisaurus aramburgi, all extracted from Morocco’s latest Maastrichtian phosphates. Scale bar – 1 m. Image credit: Nicholas R. Longrich & Nour-Eddine Jalil, doi: 10.3390/d18030159.
A 1.25 m (4.1 ft) long skull, along with the lower jaw of Pluridence Imeraki, was unearthed from the phosphate layer of Couche III in Sidi Chennan, Kouribga department, Morocco.
The phosphate layer represents a marine upwelling zone, deposited in a shallow marine embayment along the eastern edge of the Atlantic Ocean from late Maastrichtian to early Eocene times,” noted the paleontologist.
“These formations are part of vast phosphate accumulations that arose along the Tethyan Mountains and the eastern Atlantic margin during the Late Cretaceous and early Paleogene.”
Compared to related species, Pluridence Imeraki likely exhibited a distinct feeding strategy.
Variations in jaw structure, tooth shape, and eye size suggest that this species occupied unique ecological niches in the marine ecosystem at the Cretaceous’s end.
“We discovered that halisaurids were not only more diverse than previously imagined, but also exhibited greater variation in tooth morphology, jaw shape, and body size,” the researchers concluded.
“Instead of merely competing with mosasaurines, halisaurinae experienced a minor adaptive radiation during the Late Cretaceous and served as significant components of low-latitude ecosystems.”
The discovery of Pluridence Imeraki was detailed in a research paper published in this week’s edition of Diversity.
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Nicholas R. Longrich and Nour Eddin Jalil. 2026. A giant halisaurine from the late Maastrichtian of Morocco. Diversity 18(3):159; doi: 10.3390/d18030159
Source: www.sci.news
