Anas platyrhynchos (mallard) is the ancestor of almost all of the varieties of domestic ducks. Mallards can be found almost anywhere in the world, with the exception of Antarctica. They prefer a habitat of wetlands that include large amounts of vegetation. They eat a large variety of foods that include: vegetation, insects, worms, gastropods, arthropods, as well as a variety of foods provided by humans. Mating occurs from October to March, and 9-13 eggs are layed in a ground nest near water. The eggs hatch after 26-28 days, and the ducklings are led to the water by the mother hen (Rogers, 2001).
Anas platyrhynchos is a member of the family Anatidae, which is comprised of 45 genera and 157 species of ducks, geese, and swans (Howard, 2003). They are characterized by: loss of a pneumatization of the processus mandibulae medialis; loss of a notarium (reversed in Tadorna); a sternum that lacks foramina and bony striations in the pars cardiaca; a scapula with a long and pointed acromion; and a tarsometatarsus that has the medial trochlea located in a more proximal and elevated position (Ericson, 1997).
Anatidae is a member of the order Anseriformes, which also includes the families Anseranatidae and Anhimidae (screamers). Anseriformes, along with Galliformes, are thought to be among the earliest members of Neognathae. Although the sister group relationship of Anseriformes and Galliformes is very contentious (Sibley and Ahlquist, 1990; Ericson, 1996; Mindell et al., 1999; Mayr and Clarke, 2003;), the monophyly of Anseriformes is well established. Some of the synapomorphies that support this monophyly are: distinctly, ventrally excavated processus postorbitalis; palatine with the internal laminae obsolete; processus mandibularis of the quadrate inflated posterior to the quadratojugal articulation; two-condyle articulation between the quadrate and mandibula; and a tibiotarsus with the distal opening of canalis extensorius equally far from either condyle (Ericson, 1997).
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