Biometry supporting species identification from underwater images in two Mediterranean Sea urchins

The analysis of samples and in-vivo underwater images of two sea urchin species, Cidaris cidaris and Stylocidaris affinis, allowed to collect biometric parameters, such as diameter of the dermal skeleton and length of the primary spines. The ratio between the two measures proved to be a useful tool for the discrimination and specific identification of these two similar species from video analysis.