Rudderhorn

The rudderhorn replaced its ancestor the narky. Only a small population still existed in the LadyM ocean. Here they adapted specifically to the twilight zone. Their coloring is darker to match with the constant dimness and their eyes have gotten huge to see in the weak light. They swim around in small pods of 5 to 10 individuals filtering the water though their mouth. They have a slit near their chin where the water is expelled after filtering.

Like their ancestor they have 2 back external gills which absorb oxygen directly out of the water. These have become more efficient than before. Their front horn-tooth has now developed a rudder which help them swim straight in the water. They propel themselves with a horizontal tail fluke similar to a dolphin's. Males will use their horn-tooth to fight for mates and dominance. Females in general have smaller horns than males.

During mating, males secrete sperm in the water, and the female will absorb it with her skin. The sperm will travel in the hemocoel, until they reach the ovaries to fertilize the eggs. Females now retain the eggs in the womb until they hatch. There are only two eggs. They stay with their mothers for five years after birth.