Lesser spotted dogfish

This species is distinguished from all its congeners by the following characters: shallow nasoral grooves and laterally situated posterior nasal flaps (vs. no grooves and posterior flaps on the posterior border of the excurrent apertures in congeners, except in S. duhamelii); distance between the anterior nasal flaps 6-7.5 times smaller than the anterior nasal flap width (vs. 3.5-5 times smaller in S. duhamelii; two times in the other species); lower labial furrow 2.1-2.2 times smaller than mouth width (vs. more than 3 times in other species, except S. duhamelii). Colouration: color pattern with dark spots well-defined, predominantly smaller than spiracles (vs. no dark spots in S. capensis, S. comoroensis, S. hesperius, S. meadi, S. torazame, S. torrei; reticulated pattern in S. rotifer; dark spots predominantly larger than spiracles in S. cervigoni, S. garmani, S. haeckelii, S. stellaris; diffuse spots in S. duhamelii); clasper with rough terminal dermal cover (also found only in S. capensis) (Ref. 120402).