Pronunciation: ah-BEE-do-SOR-us
Meaning: Abydo (see below) lizard
Author/s: Chure et al. (2010)
Synonyms: None known
First Discovery: Utah, USA
Discovery Chart Position: #726
Abydosaurus mcintoshi
When palaeontologists began to excavate Abydosaurus from Utah's Dinosaur National Monument, they stumbled upon what can only be described as a sauropod holy grail—the ever-elusive head, and the crew were so cock-a-hoop that they accidentally sawed it in half. However, fate was feeling generous and three more followed, which is astounding given how readily sauropod crania detach from their necks and disintegrate shortly after death, not to mention the generous smidgin' of dynamite that was required to coax them from the zircon crystal-fortified rock. Frenzied scrutiny of the first complete, Cretaceous-aged sauropod skull known from the Americas ensued, and some remarkable facts were quick to follow.
Abydosaurus was caught mid-transition—from primitive chisel-shaped teeth to the not-quite-so-primitive peg-like variety, which, unlike their ornithopod contemporaries who flaunted beaks, cheeks, bone kinesis, and heterodonty, is pretty much the only "upgrade" to the sauropod foliage-cropping toolkit. With a head accounting for just 1/200th of body mass (compared to roughly 1/30th in ornithopod dinosaurs and 1/12th in humans), sauropods like Abydosaurus evolved slimmer pegged teeth to grip and strip vegetation with ruthless efficiency. Chewing? Not on the menu. Their jaws weren’t built for it. So huge wads of foliage were swallowed whole instead, and the job of processing to extract enough go-juice to power an eating machine was outsourced to a gutful of gastroliths. This was a big responsibility for humble rocks.
In addition to the type specimen, three more individuals of Abydosaurus were discovered in the same quarry (DINO 17848, 17849, 39727), each chipping in with clues about the dinosaur’s overall size and family ties. All known Abydosaurus specimens are immature, but as adults, they would've been middle-of-the-road brachiosaurids size-wise, being somewhat smaller than Giraffatitan (formerly Brachiosaurus brancai) which they most closely resemble. Despite living some 45 million years apart, the skulls of Abydosaurus and the much older Giraffatitan are remarkably similar, but the pair differ in that the latter has substantially broader teeth, while the former has nasal openings that are smaller than its eye sockets.
Abydosaurus was caught mid-transition—from primitive chisel-shaped teeth to the not-quite-so-primitive peg-like variety, which, unlike their ornithopod contemporaries who flaunted beaks, cheeks, bone kinesis, and heterodonty, is pretty much the only "upgrade" to the sauropod foliage-cropping toolkit. With a head accounting for just 1/200th of body mass (compared to roughly 1/30th in ornithopod dinosaurs and 1/12th in humans), sauropods like Abydosaurus evolved slimmer pegged teeth to grip and strip vegetation with ruthless efficiency. Chewing? Not on the menu. Their jaws weren’t built for it. So huge wads of foliage were swallowed whole instead, and the job of processing to extract enough go-juice to power an eating machine was outsourced to a gutful of gastroliths. This was a big responsibility for humble rocks.
In addition to the type specimen, three more individuals of Abydosaurus were discovered in the same quarry (DINO 17848, 17849, 39727), each chipping in with clues about the dinosaur’s overall size and family ties. All known Abydosaurus specimens are immature, but as adults, they would've been middle-of-the-road brachiosaurids size-wise, being somewhat smaller than Giraffatitan (formerly Brachiosaurus brancai) which they most closely resemble. Despite living some 45 million years apart, the skulls of Abydosaurus and the much older Giraffatitan are remarkably similar, but the pair differ in that the latter has substantially broader teeth, while the former has nasal openings that are smaller than its eye sockets.
McIntosh's Abydos LizardEtymology
The holotype skull of Abydosaurus with the first four neck vertebrae in place, was discovered in a quarry overlooking the Green River, which bears an uncanny similarity to the head and neck of Osiris, the Egyptian god of life, death, and fertility, that was buried by his brother Set (or Seth) at Abydos, the Greek name for a city overlooking the Nile river. This was a parallel too good to ignore when the subject of naming popped up. "Abydos" is combined with the Greek "sauros" (lizard).The species epithet, mcintoshi, is a long overdue cap-tip to John S. ("Jack") McIntosh for his contributions to the study of sauropod dinosaurs.
Discovery
Abydosaurus was discovered at locality DNM 16 in the Mussentuchit Member of the Cedar Mountain Formation, Dinosaur National Monument, Uintah County, Utah.
Its Holotype (DINO 16488) is an almost complete skull (500mm long, 250mm high) with the first four neck vertebrae attached.
Preparators
Crews from Dinosaur National Monument (led by S. Madsen and the late A. Elder) and Brigham Young University.
