Aralosaurus

Rozhdestvensky, 1968 AR-a-lo-SAWR-us

Named after the Aral Sea (near where the fossils were found northeast of it) combined with Greek 'sauros' meaning 'lizard'; meaning 'Aral Sea lizard'

85.7–72.2 million years ago Santonian–Campanian, Late Cretaceous

Late Cretaceous stages

Aralosaurus is a genus of hadrosaurid dinosaur that lived during the Late Cretaceous in what is now Kazakhstan. It is known only by a posterior half of a skull (devoid of its mandible) and some post-cranial bones found in the Bostobe Formation in rocks dated from the Upper Santonian–lower Campanian boundary, at about 83.6 Ma (millions of years ago). Only one species is known, Aralosaurus tuberiferus, described by Anatoly Konstantinovich Rozhdestvensky in 1968. The genus name means "Aral Sea lizard", because it was found to the northeast of the Aral Sea. The specific epithet tuberiferus means "bearing a tuber" because the posterior part of the nasal bone rises sharply in front of the orbits like an outgrowth.

Diagnosis

Nasals form a low tubercular arch creating an enlarged crest in the central region of the skull roof.
An elliptical fontanelle between the nasals and frontals, almost one-third as wide as the skull in the orbital area.
Infratemporal fenestrae narrow, barely wider than the quadrate, with a length-to-height ratio of 7:4.
Lower jaw teeth bear a supplementary crest anterior to the medial ridge, rising above the center of the crown.
Proximal end of metatarsal III is wide, comprising approximately half its entire length.

Species

Aralosaurus tuberiferus Rozhdestvensky, 1968

Type species

Means 'bearing a tuber', referring to the posterior part of the nasal bone, which rises sharply in front of the orbits like an outgrowth.

Holotype: PIN 2229/1 , Paleontological Institute, Russian Academy of Sciences
Material: Incomplete skull.
Horizon: Bostobe Formation, Santonian–Campanian, Late Cretaceous , 85.7–72.2 million years ago
Locality: Shakh-Shakh, Kyzylorda, Kazakhstan

References

Averianov, A. O.; Sues, H. D. (2007). A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union. Journal of Vertebrate Paleontology 27(1): 87-98. Informa UK Limited. doi:10.1671/0272-4634(2007)27[87:antdtf]2.0.co;2
Places Shakh-Shakh in "the upper Santonian to lower Campanian Bostobe Formation".
averianov2007a
Rozhdestvensky, A. K. (1968). Gadrozavry Kazakhstana [Hadrosaurs of Kazakhstan]. [Upper Paleozoic and Mesozoic Amphibians and Reptiles]. Akademia Naul SSSR, Moscow 97-141. rozhdestvensky1968a
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.
Source of the appearance features.
jones2026a