Saturday, February 24, 2024

[Paleontology • 2024] Minqaria bata • A New small Duckbilled Dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and Dinosaur Diversity in the late Maastrichtian of North Africa


 Minqaria bata 
Longrich, Pereda-Suberbiola, Bardet & Jalil, 2024

Reconstruction by Raul Martin 

In the Late Cretaceous, northern and southern hemispheres evolved distinct dinosaurian faunas. Titanosaurians and abelisaurids dominated the Gondwanan continents; hadrosaurids, ceratopsians and tyrannosaurs dominated North America and Asia. Recently, a lambeosaurine hadrosaurid, Ajnabia odysseus, was reported from the late Maastrichtian phosphates of the Oulad Abdoun Basin Morocco, suggesting dispersal between Laurasia and Gondwana. Here we report new fossils from the phosphates of Morocco showing lambeosaurines achieved high diversity in the late Maastrichtian of North Africa. A skull represents a new dwarf lambeosaurine, Minqaria bata. Minqaria resembles Ajnabia odysseus in size, but differs in the ventrally positioned jugal facet and sinusoidal toothrow. The animal is small, ~ 3.5 m long, but the fused braincase shows it was mature. A humerus and a femur belong to larger hadrosaurids, ~ 6 m long, implying at least three species coexisted. The diversity of hadrosaurids in Europe and Africa suggests a dispersal-driven radiation, with lambeosaurines diversifying to take advantage of low ornithischian diversity. African lambeosaurines are small compared to North American and Asia hadrosaurids however, perhaps due to competition with titanosaurians. Hadrosaurids are unknown from eastern Africa, suggesting Moroccan hadrosaurids may be part of a distinct insular fauna, and represent an island radiation.

Skull elements of Minqaria bata nov. gen. et sp., MHNM.KHG.1395, holotype: right maxilla, braincase, left dentary. Sidi Chennane, Oulad Abdoun Basin, Upper Couche III, late Maastrichtian. Scale = 5 cm.

Systematic paleontology
Dinosauria Owen, 1842
Ornithischia Seeley, 1887
Iguanodontia, Baur, 1891

Hadrosauridae Cope, 1869
Lambeosaurinae Parks, 1923
Arenysaurini Longrich, Pereda-Suberbiola, Pyron et Jalil, 2021

Minqaria bata gen. et sp. nov.

Diagnosis. Small lambeosaurine characterized by the following character combination, which also differentiates it (where the specimens overlap) from Ajnabia odysseus. Jugal articulation lies very low on maxilla (autapomorphic within lambeosaurinae); ectopterygoid ridge ends at jugal articulation. Ectopterygoid ridge concave in lateral and dorsal views, narrower posteriorly than anteriorly. Neurovascular foramina arranged in a row. Highly domed frontoparietal, with extensive contribution of parietal to the dome, and a triangular parietal table. Maxillary toothrow sinusoidal in lateral or ventral views, with a deep buccal fossa. Dentary short and deep, occlusal margin straight; symphyseal process strongly extended anteriorly, and with straight ventral margin. Alveolar ridges of maxilla and dentary poorly developed. Teeth small, with narrow apices, broad central ridges, and rugose enamel.

Locality and horizon. Sidi Chennane, Oulad Abdoun Basin, Morocco; upper Couche III, late Maastrichtian. 

Etymology. Arabic, ‘minqar’, beak; ‘bata’, duck.

A hadrosaurid from the latest Maastrichtian phosphates of Sidi Chennane, Morocco, is distinct from Ajnabia odysseus and represents a new arenysaurin, Minqaria bata. Minqaria differs from Ajnabia in jaw and tooth morphology, suggesting it occupied a distinct niche. Fusion of cranial elements shows that it was mature despite its small size (~ 3.5 m), confirming the existence of small hadrosaurids in North Africa. Similarities with the European Arenysaurus provide further evidence for dispersal of lambeosaurines between the Ibero-Armorican landmass and Africa. A humerus from Sidi Daoui and a femur from Mrah Lahrach belong to larger individuals, suggesting at least three hadrosaur species occur in the phosphates. Even as lambeosaurines declined in the Maastrichtian of North America, they diversified in Africa.

Nicholas R. Longrich, Xabier Pereda-Suberbiola, Nathalie Bardet and Nour-Eddine Jalil. 2024. A New small Duckbilled Dinosaur (Hadrosauridae: Lambeosaurinae) from Morocco and Dinosaur Diversity in the late Maastrichtian of North Africa. Scientific Reports. 14: 3665. DOI: 10.1038/s41598-024-53447-9

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