[D] Saurolophus angustirostris [Si] [Su]
Describer
Rozhdestvensky, 1952
Time
Cretaceous Late Campanian Maastrichtian
Classification
Ornithischia Ornithopoda Hadrosauridae Hadrosaurinae Gryposaurini Saurolophini
Diet
Herbivore
Fossilsite
Nemegt Formation, Omnogov; White Beds of Khermeen Tsav, Nemegtskaya Svita, Bayankhongor; Mongolia
Fall under
Saurolophus
Info
Skin - Skull
Saurolophus (Brown, 1912) > Saurolophus osborni (Brown, 1912)
Saurolophus (Brown, 1912) > Saurolophus angustirostris (Rozhdestvensky, 1952)
At least 15 specimens including articulated skull and postcranial skeleton. Its possible that Saurolophus angustrirostris is conspecific with Saurolophus osborni. The anatomical characters listed for Saurolophus angustirostris may well fall whitin the normal range of intraspecific variability.
Bell, P.R. 2011. Cranial osteology and ontogeny of Saurolophus angustirostris from the Late Cretaceous of Mongolia with comments on Saurolophus osborni from Canada. Acta Palaeontologica Polonica 56 (4): 703–722.
Abstract
Reanalysis of the skull of the crested Asian hadrosaurine Saurolophus angustirostris confirms its status as a distinct species from its North American relative, Saurolophus osborni.
In addition to its greater absolute size, S. angustirostris is differentiated from Saurolophus osborni by an upturned premaxillary body, a more strongly reflected oral margin of the premaxilla, the absence of an anterior notch in the prenarial fossa, a sigmoidal contour of the ventral half of the anterior process of the jugal, a shallow quadratojugal notch on the quadrate, and by a strongly bowed quadrate in lateral view.
Phylogenetic analysis corroborates a sister taxon relationship between S. angustirostris and S. osborni.
Saurolophus itself is characterised by a solid, rod−like crest composed of the nasals, frontals, and prefrontals; secondary elongation of the frontal and prefrontal resulting in the backwards extension of the frontal platform; a frontal platform that extends dorsal to the anterior portion of the supratemporal fenestra; a parietal that is excluded by the squamosals from the posterodorsal margin of the occiput; and the presence of two supraorbital elements. Although the palaeobiogeographic history of Saurolophus remains unresolved, at least two possible dispersal events took place across Beringia during the late Campanian leading to the evolution of the clade composed of Kerberosaurus, Prosaurolophus, and Saurolophus.
Holotype
PIN 551/8
Type locality
Nemegt, Mongolia
Type horizon
Nemegt Formation (?upper Campanian/lower Maastrichtian), Upper Cretaceous.
Emended diagnosis
Differs from S. osborni in having a skull that is at least 20% longer among the largest adults; premaxilla with strongly reflected oral margin and upturned premaxillary body in lateral aspect; broadly arcing anterior margin of the prenarial fossa; an elongate, anteriorly directed spur on the anterior process of the jugal that separates the lacrimal and maxilla, more so than in S. osborni; shallow quadratojugal notch on the quadrate; and more strongly bowed quadrate in lateral view.
Rozhdestvensky, 1952
Time
Cretaceous Late Campanian Maastrichtian
Classification
Ornithischia Ornithopoda Hadrosauridae Hadrosaurinae Gryposaurini Saurolophini
Diet
Herbivore
Fossilsite
Nemegt Formation, Omnogov; White Beds of Khermeen Tsav, Nemegtskaya Svita, Bayankhongor; Mongolia
Fall under
Saurolophus
Info
Skin - Skull
Saurolophus (Brown, 1912) > Saurolophus osborni (Brown, 1912)
Saurolophus (Brown, 1912) > Saurolophus angustirostris (Rozhdestvensky, 1952)
At least 15 specimens including articulated skull and postcranial skeleton. Its possible that Saurolophus angustrirostris is conspecific with Saurolophus osborni. The anatomical characters listed for Saurolophus angustirostris may well fall whitin the normal range of intraspecific variability.
Bell, P.R. 2011. Cranial osteology and ontogeny of Saurolophus angustirostris from the Late Cretaceous of Mongolia with comments on Saurolophus osborni from Canada. Acta Palaeontologica Polonica 56 (4): 703–722.
Abstract
Reanalysis of the skull of the crested Asian hadrosaurine Saurolophus angustirostris confirms its status as a distinct species from its North American relative, Saurolophus osborni.
In addition to its greater absolute size, S. angustirostris is differentiated from Saurolophus osborni by an upturned premaxillary body, a more strongly reflected oral margin of the premaxilla, the absence of an anterior notch in the prenarial fossa, a sigmoidal contour of the ventral half of the anterior process of the jugal, a shallow quadratojugal notch on the quadrate, and by a strongly bowed quadrate in lateral view.
Phylogenetic analysis corroborates a sister taxon relationship between S. angustirostris and S. osborni.
Saurolophus itself is characterised by a solid, rod−like crest composed of the nasals, frontals, and prefrontals; secondary elongation of the frontal and prefrontal resulting in the backwards extension of the frontal platform; a frontal platform that extends dorsal to the anterior portion of the supratemporal fenestra; a parietal that is excluded by the squamosals from the posterodorsal margin of the occiput; and the presence of two supraorbital elements. Although the palaeobiogeographic history of Saurolophus remains unresolved, at least two possible dispersal events took place across Beringia during the late Campanian leading to the evolution of the clade composed of Kerberosaurus, Prosaurolophus, and Saurolophus.
Holotype
PIN 551/8
Type locality
Nemegt, Mongolia
Type horizon
Nemegt Formation (?upper Campanian/lower Maastrichtian), Upper Cretaceous.
Emended diagnosis
Differs from S. osborni in having a skull that is at least 20% longer among the largest adults; premaxilla with strongly reflected oral margin and upturned premaxillary body in lateral aspect; broadly arcing anterior margin of the prenarial fossa; an elongate, anteriorly directed spur on the anterior process of the jugal that separates the lacrimal and maxilla, more so than in S. osborni; shallow quadratojugal notch on the quadrate; and more strongly bowed quadrate in lateral view.