Dogfish or Catshark?

Dogfishes and catsharks can be difficult to differentiate. Both are typically smallish (1 to 4 feet or 30 to 120 centimetres), bottom-associated elasmobranchs sharing a similar 'sharky' shape and some of the most familiar forms occur together in coastal habitats. Adding to the confusion, some catsharks (especially those of the genus Scyliorhinus) are often referred to as "dogfishes". But once one has learned their respective field marks, it is relatively easy to distinguish dogfishes from catsharks.

Dogfishes (order Squaliformes):

lack an anal fin
the first dorsal fin originates well in front of the pelvic fins
most have a sharp spine along the leading edge of each dorsal
are generally stockier than catsharks

Catsharks (family Scyliorhinidae):

have an anal fin
the first dorsal fin originates over or behind the pelvic fins
do not have spines on their dorsal fins
are generally more slender than dogfishes

In addition, dogfishes are generally rather drab creatures (gray above, paler below) but many catsharks are boldly and attractively patterned (the back may be marked with any combination of stripes, bars, blotches, and spots — often in various shades of brown, orange, or yellow). But since color and pattern can vary greatly among individuals, physical features such as those listed in point-form above are generally more reliable for distinguishing dogfishes from catsharks.