TY - JOUR AU - Farke, Andrew AU - Yip, Eunice PY - 2019/05/01 Y2 - 2024/03/28 TI - A juvenile cf. Edmontosaurus annectens (Ornithischia, Hadrosauridae) femur documents a poorly represented growth stage for this taxon JF - Vertebrate Anatomy Morphology Palaeontology JA - Vert. Anat. Morph. Palaeo. VL - 7 IS - 0 SE - Articles DO - 10.18435/vamp29347 UR - https://journals.library.ualberta.ca/vamp/index.php/VAMP/article/view/29347 SP - AB - <p><span style="font-family: 'Times New Roman', serif;"><span style="font-size: medium;"><strong> </strong><span>A nearly complete, but isolated, femur of a small hadrosaurid from the Hell Creek Formation of Montana is tentatively referred to </span><em><span>Edmontosaurus annectens</span></em><span><span>. At </span></span><span><span>28</span></span><span><span> cm long, </span></span><span><span>the element</span></span><span><span> can be classified as </span></span><span><span>that from </span></span><span><span>an “early juvenile” individual, approximately </span></span><span><span>24</span></span><span><span> percent of the maximum known femur length for this species. Specimens from this size range and age class have not been described previously for </span></span><em><span>E. annectens</span></em><span><span>. </span></span><span><span>Notable trends</span></span><span><span> with increasing body size include </span></span><span><span>increasingly</span></span><span><span> distinct separation of the femoral head and greater trochanter, relative increase in the size of the cranial trochanter, a slight reduction in the relative </span></span><span><span>breadth</span></span><span><span> of the fourth trochanter, and a relative increase in the prominence of the cranial intercondylar groove. The gross profile of the femoral shaft is fairly consistent between the smallest and largest individuals. Although a</span></span><span><span>n ontogenetic change</span></span><span><span> from relatively symmetrical to </span></span><span><span>an </span></span><span><span>asymmetrical shape in the fourth trochanter has been </span></span><span><span>suggested previously</span></span><span><span>, the </span></span><span><span>new juvenile specimen shows an asymmetric fourth trochanter. Thus, there may not be a consistent ontogenetic pattern in trochanteric morphology. An isometric relationship between femoral circumference and femoral length is confirmed for </span></span><em><span>Edmontosaurus</span></em><span><span>. Overall ontogenetic trends in the femur of </span></span><em><span>Edmontosaurus </span></em><span><span>are </span></span><span><span>concordant</span></span><span><span> with patterns seen in other Hadrosauridae, </span></span><span><span>supporting</span></span><span><span> a fairly conserved pattern of development for this element </span></span><span><span>within</span></span><span><span> the clade.</span></span></span></span></p> ER -