Maganuco S, Dal Sasso C. The smallest biggest theropod dinosaur: a tiny
pedal ungual of a juvenile
Spinosaurus from the Cretaceous of Morocco.
PeerJ 2018;
6:e4785. [PMID:
29868253 PMCID:
PMC5984586 DOI:
10.7717/peerj.4785]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/27/2018] [Indexed: 11/20/2022] Open
Abstract
We describe a nearly complete pedal ungual phalanx, discovered in the Kem Kem Beds (Cenomanian) of Tafilalt region, south-eastern Morocco. The bone is symmetric, pointed, low, elongate, and almost flat ventrally in lateral aspect. This peculiar morphology allows to refer the specimen to the smallest known individual of the genus Spinosaurus. The bone belongs to an early juvenile individual and it is proportionally identical to the ungual of the third digit of a large partial skeleton recently found, suggesting an isometric growth for this part of the pes and the retention of peculiar locomotor adaptations—such as traversing soft substrates or paddling—during the entire lifespan.
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