1. General Body Shape:
- Squalidae (Dogfish Sharks): Squalidae sharks have a streamlined body shape, with a relatively elongated and slender snout. Their dorsal fins are usually positioned towards the back of the body, and the caudal fin is typically notched.
- Pristiophoridae (Sawsharks): Pristiophoridae sharks are characterized by their distinctive elongated and flattened snout, resembling a saw. The snout is lined with sharp, tooth-like projections called rostral teeth. Their dorsal fins are located further forward on the body, and the caudal fin is often asymmetrical, with the lower lobe longer than the upper lobe.
2. Snout:
- Squalidae: Squalidae sharks have a relatively short and blunt snout.
- Pristiophoridae: Pristiophoridae sharks have a long and flattened snout, equipped with rostral teeth. The rostral teeth can vary in size, shape, and number depending on the species.
3. Dorsal Fins:
- Squalidae: Squalidae sharks typically have two dorsal fins, with the first dorsal fin being larger than the second.
- Pristiophoridae: Pristiophoridae sharks also have two dorsal fins, but the first dorsal fin is positioned further forward on the body and is usually larger in size compared to Squalidae sharks.
4. Caudal Fin:
- Squalidae: Squalidae sharks generally have a notched or indented caudal fin.
- Pristiophoridae: Pristiophoridae sharks typically have an asymmetrical caudal fin, with the lower lobe being longer than the upper lobe.
5. Coloration:
- Squalidae: Squalidae sharks often exhibit a variety of colors and patterns, including shades of brown, gray, or black, sometimes with contrasting markings.
- Pristiophoridae: Pristiophoridae sharks typically have a brown or gray coloration, often with dark spots or markings.
It's important to note that while these characteristics can usually distinguish between Squalidae and Pristiophoridae sharks, there may be some species within each family that exhibit variations in these traits. In cases of uncertain identification, it is recommended to consult taxonomic experts or refer to detailed scientific resources.