Figure 5. The relationship between neck length and C3 vertebral length throughout ontogeny in giraffes and okapis.

A regression line is based on the giraffe ontogenetic series and is extrapolated to the okapi range. The use of a regression line for ontogenetic and phylogenetic allometry seems to be appropriate in this case, supporting the use of a giraffe ontogenetic regression line to predict a neck length value for G. sivalensis.