Loggerhead sea turtle although loggerhead sea turtles cannot retract their heads or flippers into their shells. Sexual dimorphism of the loggerhead sea turtle is only apparent in adults. Adult males have longer tails and claws than females. The males' plastrons are shorter than the females', presumably to accommodate the males' larger tails. The carapaces of males are wider and less domed than the females', and males typically have wider heads than females. The sex of juveniles and subadults cannot be determined through external anatomy, but can be observed through dissection, laparoscopy (an operation performed on the abdomen), histological examination (cell anatomy), and radioimmunological
Varieties of Chinese dialect of northern Fujian is a minimal example. With the exception of , which is often merged with the zero initial, the initials of this dialect are present in all Chinese varieties, although several varieties do not distinguish from . However, most varieties have additional initials, due to a combination of innovations and retention of distinctions from Middle Chinese: Chinese finals may be analysed as an optional medial glide, a main vowel and an optional coda. Conservative vowel systems, such as those of Gan dialects, have high vowels , and , which also function as medials, mid vowels and ,