Variation in stable carbon (δC) and nitrogen (δN) isotope compositions along antlers of Qamanirjuaq caribou ().

Annual antler growth begins in the spring and is completed by late summer for male caribou () from the Qamanirjuaq herd (Nunavut, Canada), aligned with both the spring migration and a seasonal dietary shift. Antlers may provide a non-lethal means of studying short- and long-term changes in caribou ecology through incorporated isotopes of carbon (δC) and nitrogen (δN). We sampled the antlers of 12 male caribou from the Qamanirjuaq herd culled in September 1967.

A new model of forelimb ecomorphology for predicting the ancient habitats of fossil turtles.

Various morphological proxies have been used to infer habitat preferences among fossil turtles and their early ancestors, but most are tightly linked to phylogeny, thereby minimizing their predictive power. One particularly widely used model incorporates linear measurements of the forelimb (humerus + ulna + manus), but in addition to the issue of phylogenetic correlation, it does not estimate the likelihood of habitat assignment. Here, we introduce a new model that uses intramanual measurements (digit III metacarpal + non-ungual phalanges + ungual) to statistically estimate habitat likelihood and that has greater predictive strength than prior estimators.