HOME | DD

Description
The most cursed of skeletal subjects. Although it's no longer the oldest known dinosaurian apex predator, the presence of multiple individuals of Dilophosaurus, representing almost a fully complete skeleton between them, makes it essential to our knowledge of what the earliest large theropods looked like. The strange anatomy of its skull puzzled paleontologists for a long time, as it was thought that the notched upper jaw was too weak to handle the stress of struggling prey; explanations for this ranged from a piscivorous diet to the animal having been an obligate scavenger. As Marsh & Rowe (2020) point out, the skull isn't as delicate as previously thought, and its ziphodont condition, the local arid habitat, and bite marks on the small sauropodomorph Sarahsaurus confirm that Dilophosaurus preyed on terrestrial animals, although mostly ones much smaller than itself.

The tall paired crests on the snout were only discovered long after the initial description of the holotype, UCMP 37302. Although generally assumed to have been the base for a keratin casque like in cassowaries, studies of the texture of nasolacrimal crests in other theropods suggest that they were the base for extensions of the sinuses, and this may have been the case for Dilophosaurus as well. More knowledge of the soft tissue is given by resting imprints of related animals, which detail things like the hand posture when sitting, the presence of ischiatic calluses and (debated) protofeather imprints.

References:
--Gilmore, C.W. (1920). "Osteology of the carnivorous Dinosauria in the United States National Museum, with special reference to the genera Antrodemus (Allosaurus) and Ceratosaurus" (PDF). Bulletin of the United States National Museum. 110 (110): 1–154. doi :10.5479/si.03629236.110.i .
-Milner, Andrew R.C.; Harris, J.D.; Lockley, M.G.; Kirkland, J.I.; Matthews, N.A.; Harpending, H. (2009). "Bird-like anatomy, posture, and behavior revealed by an Early Jurassic theropod dinosaur resting trace" . PLOS ONE. 4 (3): e4591.
-Senter, P.; Robins, J.H. (2015). "Resting orientations of dinosaur scapulae and forelimbs: A numerical analysis, with implications for reconstructions and museum mounts" . PLOS ONE. 10 (12): e0144036.
-Marsh, A.D.; Rowe, T.B. (2020). "A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona". Journal of Paleontology. 94 (S78): 1–103. doi :10.1017/jpa.2020.14 .

Description
The most cursed of skeletal subjects. Although it's no longer the oldest known dinosaurian apex predator, the presence of multiple individuals of Dilophosaurus, representing almost a fully complete skeleton between them, makes it essential to our knowledge of what the earliest large theropods looked like. The strange anatomy of its skull puzzled paleontologists for a long time, as it was thought that the notched upper jaw was too weak to handle the stress of struggling prey; explanations for this ranged from a piscivorous diet to the animal having been an obligate scavenger. As Marsh & Rowe (2020) point out, the skull isn't as delicate as previously thought, and its ziphodont condition, the local arid habitat, and bite marks on the small sauropodomorph Sarahsaurus confirm that Dilophosaurus preyed on terrestrial animals, although mostly ones much smaller than itself.

The tall paired crests on the snout were only discovered long after the initial description of the holotype, UCMP 37302. Although generally assumed to have been the base for a keratin casque like in cassowaries, studies of the texture of nasolacrimal crests in other theropods suggest that they were the base for extensions of the sinuses, and this may have been the case for Dilophosaurus as well. More knowledge of the soft tissue is given by resting imprints of related animals, which detail things like the hand posture when sitting, the presence of ischiatic calluses and (debated) protofeather imprints.

References:
--Gilmore, C.W. (1920). "Osteology of the carnivorous Dinosauria in the United States National Museum, with special reference to the genera Antrodemus (Allosaurus) and Ceratosaurus" (PDF). Bulletin of the United States National Museum. 110 (110): 1–154. doi :10.5479/si.03629236.110.i .
-Milner, Andrew R.C.; Harris, J.D.; Lockley, M.G.; Kirkland, J.I.; Matthews, N.A.; Harpending, H. (2009). "Bird-like anatomy, posture, and behavior revealed by an Early Jurassic theropod dinosaur resting trace" . PLOS ONE. 4 (3): e4591.
-Senter, P.; Robins, J.H. (2015). "Resting orientations of dinosaur scapulae and forelimbs: A numerical analysis, with implications for reconstructions and museum mounts" . PLOS ONE. 10 (12): e0144036.
-Marsh, A.D.; Rowe, T.B. (2020). "A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona". Journal of Paleontology. 94 (S78): 1–103. doi :10.1017/jpa.2020.14 .