sentences:  One or two pups are born at a time; the newborns are extremely large relative to their mothers, measuring around in length.Males reach sexual maturity at a length of and females at perhaps .This is comparable to the sizes at maturity of the spined pygmy shark ("Squaliolus laticaudus") and the dwarf lanternshark ("Etmopterus perryi"), ranking the pygmy ribbontail catshark among the world's smallest sharks.