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Fantastic Find -- Baby Horned Face

Just like animals alive today, dinosaurs changed a lot as they grew up from hatchling to adult. But, evidence of these transformations are often scarce. Young, small dinosaurs were...well, bite-sized, and often didn't make it into the fossil record. And even if they did, their delicate bones are usually destroyed by erosion or even overlooked by collectors.

Baby Chasmosaurus Skeleton
Above: Skeleton of baby Chasmosaurus, from Currie et al. 2016

Paleontologist Phil Currie (University of Alberta) had the phenomenal luck to discover the virtually complete skeleton of a young horned dinosaur, Chasmosaurus. The fossil was found in roughly 76 million year old rocks in southern Alberta, Canada. Adults and teenagers of this cousin to Triceratops have been known for over 100 years, but "babies" previously were represented only by a handful of fragments. Currie and a team of paleontologists (Rob Holmes, Michael Ryan, and Clive Coy) just published the full description of the fossil in Journal of Vertebrate Paleontology.

The baby Chasmosaurus was roughly the size of a golden retriever, and around a quarter of the size of an adult Chasmosaurus. Compared to full-grown individuals, the little critter had much smaller horns on its face and a neck frill that was much shorter and narrower. Speculatively, these changes may have helped individuals to recognize each other as juveniles or adults, whether for establishing pecking order or figuring out who was ready to reproduce.

Baby and adult Chasmosaurus, next to adult human
Above: "Baby" Chasmosaurus skeleton next to adult Chasmosaurus, with human for scale. "Baby" modified from Currie et al. 2016, human and adult dinosaurs by Farke, via PhyloPic.

Documentation of dinosaurs at various life stages helps untangle another thorny situation--how many species of dinosaurs were there? Young animals haven't always been recognized as such and sometimes were named as species distinct from their adult forms. By carefully documenting the differences between young and old animals, paleontologists can help sweep up and avoid an overinflation of the dinosaur species count. The new work is part of a rapidly expanding body of research in this area.

Scientific importance aside, this baby Chasmosaurus is also pretty darned cute! We're lucky indeed to have this remarkable fossil.

Citation
Currie, P. J., R. B. Holmes, M. J. Ryan, and C. Coy. 2016. A juvenile chasmosaurine ceratopsid (Dinosauria, Ornithischia) from the Dinosaur Park Formation, Alberta, Canada. Journal of Vertebrate Paleontology:e1048348.

Post by Andy Farke, Raymond M. Alf Museum of Paleontology
Posted: 1/14/2016 12:00:00 AM by host | with 0 comments
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