Pronunciation: SHAH-maw-SOR-us
Meaning: Desert lizard
Author/s: Tumanova (1983)
Synonyms: None known
First Discovery: Dornogovi, Mongolia
Discovery Chart Position: #304
Shamosaurus scutatus
Because so little of Shamosaurus is known, remains-wise, little of Shamosaurus is, well, known. Its fossils amount to a skull from Khamryn-Us, plus a partial skull from the same area, and an as-yet undescribed lower jaw from Höövör. But nevertheless, it sports some features that make its identification at family level unmistakable.
The roof of its noggin is completely covered in low pyramid-like armour plates so we know it's an ankylosaurid of some stamp but several design quirks mark it out as unique. Its skull is 36cm long, 26cm wide between its eye sockets and widest (37cm across) between two roughly triangular armour plates jutting out from its "cheeks". Its teeth, shaped roughly like a human hand with the fingers pressed together but bulbous at the base, are large for an ankylosaurid, its jaw joint is located far behind the rear edge of its eye socket and its upper jaw tooth row is around 50% of the total skull length. Unfortunately, nothing of its skeleton is known but paleontologists reckon it was no patsy at around five-six meters long and maybe a couple of tons in weight.
Shamosaurus is the most primitive ankylosaurid, the oldest known from Asia, and the first known from the Early Cretaceous of Mongolia. Strangely, it shares some skull features with nodosaurids (the armourless, lightweight-by-comparison branch of Ankylosauridae), but its closest relative is Gobisaurus—another "desert lizard", and from the same area, no less—though they lived some five million years apart.
The roof of its noggin is completely covered in low pyramid-like armour plates so we know it's an ankylosaurid of some stamp but several design quirks mark it out as unique. Its skull is 36cm long, 26cm wide between its eye sockets and widest (37cm across) between two roughly triangular armour plates jutting out from its "cheeks". Its teeth, shaped roughly like a human hand with the fingers pressed together but bulbous at the base, are large for an ankylosaurid, its jaw joint is located far behind the rear edge of its eye socket and its upper jaw tooth row is around 50% of the total skull length. Unfortunately, nothing of its skeleton is known but paleontologists reckon it was no patsy at around five-six meters long and maybe a couple of tons in weight.
Shamosaurus is the most primitive ankylosaurid, the oldest known from Asia, and the first known from the Early Cretaceous of Mongolia. Strangely, it shares some skull features with nodosaurids (the armourless, lightweight-by-comparison branch of Ankylosauridae), but its closest relative is Gobisaurus—another "desert lizard", and from the same area, no less—though they lived some five million years apart.
(Armoured desert lizard)
Etymology
Shamosaurus is derived from "shamo" (an old
Mongolian term for the Gobi Desert, from sha "sand" and mo "desert") and the Greek "sauros" (lizard). The species epithet, scutatus, means "armed with shields" in Latin.
Discovery
The remains of Shamosaurus were discovered in the Dzunbain Formation at Khamryn-Us (aka Chamrin-Us, Gashun-Khuduk), Dornogovi (south-east
Gobi), Mongolia, in 1977.The holotype (PIN N 3779/2) is a skull. Referred material includes a partial skull from the same locality and an as-yet undescribed lover jaw from Höövör.
