Giraffid

Evolutionary background

The fossil record of giraffids and their stem-relatives is quite intensive, with fossil of these taxa include Gelocidae, Palaeomerycidae, Prolibytheridae, and Climacoceratidae. It is thought that the palaeomerycids, prolibytherids, climacoceratids and the giraffids all form a clade of pecorans known as Giraffomorpha. The relationship between the climacoceratids and giraffids is supported by the presence of a bilobed canine, and have been postulated into two hypotheses. One is the climacoceratids were the ancestors of the sivatheres, as both groups were large, deer-like giraffoids with branching antler-like ossicones, while an extinct basal group of giraffoids, canthumerycines, evolved into the ancestors of Giraffidae. Another more commonly supported hypothesis is climacoceratids were merely the sister clade to giraffids, with sivatheres being either basal giraffids or descended from a lineage that also includes the okapi. While the current range of giraffids today is in Africa, the fossil record of the group has shown this family was once widespread throughout of Eurasia.