Tag: chasmosaurinae

Sierraceratops

In the late 1990s a partial skeleton of a ceratopsian was discovered in New Mexico, USA. These remains were initially thought to belong to Torosaurus, but after more of the specimen was recovered in the mid-2010s it became clear the bones actually represented an entirely new species of horned dinosaur – officially named in 2022 as Sierraceratops turneri.

Sierraceratops lived during the Late Cretaceous, around 72 million years ago, in what at the time was the southern region of the island continent of Laramidia. About 4.6m long (~15′), it had fairly short chunky brow horns, long pointed cheek horns, and a relatively large frill.

It was part of a unique lineage of ceratopsians that were endemic to southern Laramidia, with its closest known relatives being Bravoceratops from western Texas and Coahuilaceratops from northern Mexico.

Unsolved Paleo Mysteries Month #16 – Strange Snoots 2: Oddball Ornithischians

Those extinct horses weren’t the only ancient creatures with unexplained noses. Some dinosaurs had equally weird things going on with their snouts – and while hadrosaurs’ big honkin’ snoots are fairly well-known, there were other ornithischians with their own bizarre nasal anatomy.

An illustration of the skull of an extinct horned dinosaur, showing the unusually large nasal cavity. Below is a reconstruction of the dinosaur's head in life.
Triceratops horridus skull and head reconstruction

Many ceratopsids had an enormous nasal opening forming a giant bony “window” through their snout, with the chasmosaurines like the famous Triceratops having additional bony projections and hollowed regions within these holes. They probably supported some huge elaborate cartilage structures in life, but what they were for is still a mystery. They may have helped with heat dissipation or moisture conservation, aided sound production, provided a highly sensitive sense of smell, housed a vomeronasal organ, held part of an air-filled pneumatic system… or, getting more speculative, possibly even some sort of inflatable nasal display structure.

An illustration of the skull of an extinct armored dinosaur, showing the multiple holes inside the nasal cavity. Below is a reconstruction of the dinosaur's head in life.
Minotaurasaurus ramachandrani skull and head reconstruction

Some ankylosaurids, meanwhile, went with multiple holes instead. Minotaurasaurus here had two additional openings around its nostrils, and Pinacosaurus could have up to five – the purpose of which is unknown. Many ankylosaurs also had forward-facing nostrils (a rare trait in archosaurs) and incredibly complex looping airways through their skulls. These may have allowed for mammal-like “air conditioning”, regulating the heat and moisture content of each breath, or perhaps enhanced their sense of smell or served some sort of resonance chamber function. Or, again, maybe even nose balloons.

Also floofy ankylosaur because I can.