Step 15: Use the lines on the frill as guides to draw the Styracosaurus' frill spikes. Just like with the nose horn, follow the path of the guide as you draw the shape of the spike around it. The base of the spikes should be wide, and the tops should end in pointy tips. Curve the shapes of the spikes outward. The spikes on the left will overlap each other a bit. You can also make the dinosaur's spikes a bit longer or shorter if you'd like.
Step 16: Continue adding more spikes along the edge of the frill guide. If you're having a hard time drawing the spikes freehand, draw a few guide lines first. Make the spikes smaller the farther down the frill they are.
Step 17: Keep drawing smaller spikes along the edges of the frill guide. These spikes should be similar to small triangles. The side of the frill should come in toward the eye a bit. Add a few curved, broken lines inside the frill to emphasize the rough texture. Add a couple of tiny triangle- shaped spikes at the top of the Styracosaurus' frill.
Step 18: Use the second line from the left as a guide to draw the Styracosaurus' first front leg. Follow the path of the guide and lightly sketch the shape of the leg around it. When you get the shape and size of the leg right, darken the lines. Add a few extra lines at the joints for the folds on the skin. Draw a series of small triangle- like shapes at the bottom for the toes and hoof-like nails. The bottom of the foot should be wide and flat. The dinosaur's toes should be short and stubby. Use curved lines to draw the shape of the leg to emphasize the muscle structure. Add a few more lines within the shape for more folds on the skin.
Step 19: Use the sloping line on the left side as a guide to draw the other front leg the same way. Follow the path of the guide and draw the shape of the leg around it. Curve the shape of the leg so that it's raised and stepping forward. Because the Styracosaurus' leg is raised, the row of hoof-like nails will be at the bottom. Add curved lines along the way at the joints for the skin's wrinkles.