Evidence of head-hunting, selective bone sampling and incomplete collection of major Late Cretaceous dinosaur skeletons in southern Alberta, Canada: A cautionary note on true specimen completeness to fieldworkers and researchers everywhere

TANKE, Darren H; Royal Tyrrell Museum of Palaeontology, Drumheller, AB.


Researching dinosaur sites of mostly pre-WWII vintage in southern Alberta has uncovered a troubling and growing realization. During fieldwork long ago, some skeletons had parts removed and the rest abandoned. Skulls, limbs, and perhaps single bones were selectively taken. In some cases, bones were accidently left behind, especially in widely disarticulated skeletons. 100+ years of erosion reveals new bones the first collectors missed. An example of the latter is noted here.

In 2007, the author found an accumulation of short lengths of old wire and a nail in the badlands of Dinosaur Provincial Park. A site visit in 2018 revealed a distal ankylosaur tibia emerging from the rock. Excavation revealed a loosely articulated ankylosaur femur and scattered ossicles. A tiny piece of plaster was also found. These new items and the wire/nail suggested this might represent an old quarry, yet none was visible. A short distance away, a sandstone outcrop with a long, narrow wedge of clay was exposed and the author recalled seeing a similar feature in a historical field photo. The relocated photo matched our site and was identified as an American Museum of Natural History (AMNH) ankylosaur quarry from 1913. Additional historical information found later showed the site was also worked in 1914. Using the 1913-1914 AMNH specimen lists, by process of elimination it was determined that this site was likely AMNH 5337, one of the most complete Euoplocephalus specimens known. 2018-2019 work by the Royal Tyrrell Museum (TMP) revealed more disarticulated in situ bones: a metatarsal, ossicles, two osteoderms, ischium, two spaced parallel rows of tail club tendons and a perfect 1.7 metre long tail club. An edge of the original and now filled in quarry was also found and 1913 newspaper scraps recovered.

This research provides a cautionary note. Unless the skeleton is just starting to emerge from the rock, it is possible that it has been seen by previous fieldworkers who may even have sampled bones from it. Long-term erosion masks or hides any clues as to their earlier digging. Knowing who, when and where the missing bones are today may prove problematic in the absence of good field notes, maps, and especially site photographs showing the skyline. Presently the skeletal remains of this Euoplocephalus are curated in at least two institutions and bear two known catalog numbers (AMNH 5337 and TMP 2018.012.0151). The author is aware of about two dozen skeletons in Alberta similarly affected by this sloppy collecting or sampling. Can we reassociate such specimens via repatriation, sharing of data, casts or 3D scans?