Geometric morphometries in the characterisation of the cranial growth pattern of Adriatic sturgeon Acipenser naccarii

Geometric morphometrics are a set of recently developed techniques in the s tudy of biological forms. In this paper these techniques are used in the ch aracterisation of shape changes of the cranial region during growth of the Adriatic sturgeon Acipenser naccarii. Species identification in sturgeons i s sometimes difficult, biased by morphological plasticity, by individual va riability, complicated by human intervention and manipulation, such as aqua culture, hybridisation, pollution and shape changes during growth (allometr y). Characteristic changes in head morphology during subadult growth concer n the relative shortening and the lateral stretching of the entire head reg ion. These and other observed shape changes were never previously visualise d nor reported in the literature. Geometric morphometrics is proposed as a good candidate to became the universal methodology in the morphometrical an alysis of sturgeons.