Information:  - The water kingfishers or Cerylidae are one of the three families of kingfishers , and are also known as the cerylid kingfishers . All six American species are in this family . These are all specialist fish - eating species , unlike many representatives of the other two families , and it is likely that they are all descended from fish - eating kingfishers which founded populations in the New World . It was believed that the entire group evolved in the Americas , but this seems not to be true . The original ancestor possibly evolved in Africa -- at any rate in the Old World -- and the Chloroceryle species are the youngest ones . Not longer than 5 million years ago -- possibly as recently as 2.9 million years ago -- an Old World giant kingfisher became the ancestor of the belted and ringed kingfishers , and later , another species related to the pied kingfisher became the ancestor of the Chloroceryle green kingfishers after colonizing the Americas . While the evolutionary history of the water kingfishers in regard to their internal relationships is well resolved , it is not entirely clear whether they evolved from river kingfishers or tree kingfishers , and whether they immigrated across the Atlantic or the Pacific Ocean ( though the former seems more likely ) . There are 9 water kingfisher species in three genera : The four large crested kingfishers , Megaceryle , have a wide distribution in Africa , Asia and America . The belted kingfisher , M. alcyon , is the only kingfisher that is widespread in North America , though M. torquata may be found as far north as Texas and Arizona . giant kingfisher ( Megaceryle maxima ) crested kingfisher ( Megaceryle lugubris ) belted kingfisher ( Megaceryle alcyon ) ringed kingfisher ( Megaceryle torquata ) The pied kingfisher ( Ceryle rudis ) , the only member of Ceryle , is widespread in the tropical regions of the Old World . The four American green kingfishers ( Chloroceryle ) of tropical America . Amazon kingfisher ( Chloroceryle amazona ) green kingfisher ( Chloroceryle...  - The river kingfishers or Alcedininae, are one of the three subfamilies of birds in the kingfisher group. The Alcedinidae once included all kingfishers, before the widespread recognition of Halcyoninae (tree kingfishers) and Cerylinae (water kingfishers). The subfamily is widespread through Africa and east and south Asia as far as Australia, with one species, the common kingfisher ("Alcedo atthis") also appearing in Europe and northern Asia. The origin of the family is thought to have been in Asia.  - Plumage ("feather") refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies, and may vary with age classes. Within species there can be different colour morphs.  - Kingfishers are a group of small to medium-sized, brightly colored birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species found outside of the Americas. The group is treated either as a single family, the Alcedinidae, or as a suborder Alcedines containing three families, Alcedinidae (river kingfishers), Halcyonidae (tree kingfishers), and Cerylidae (water kingfishers). Roughly 90 species of kingfishers are described. All have large heads, long, sharp, pointed bills, short legs, and stubby tails. Most species have bright plumage with few differences between the sexes. Most species are tropical in distribution, and a slight majority are found only in forests. They consume a wide range of prey, as well as fish, usually caught by swooping down from a perch. While kingfishers are usually thought to live near rivers and eat fish, most species live away from water and eat small invertebrates. Like other members of their order, they nest in cavities, usually tunnels dug into the natural or artificial banks in the ground. A quarter of all kingfishers nest in abandoned termite nests. A few species, principally insular forms, are threatened with extinction. In Britain, the word "kingfisher" normally refers to the common kingfisher.  - Birds (Aves), also known as avian dinosaurs, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds or, less accurately, as songbirds.  - The Coraciiformes are a group of usually colorful birds including the kingfishers, the bee-eaters, the rollers, the motmots, and the todies. They generally have syndactyly, with three forward-pointing toes (and toes 3 & 4 fused at their base), though in many kingfishers one of these is missing.  - In biology and ecology, extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence.  - The common kingfisher ("Alcedo atthis") also known as the Eurasian kingfisher, and river kingfisher, is a small kingfisher with seven subspecies recognized within its wide distribution across Eurasia and North Africa. It is resident in much of its range, but migrates from areas where rivers freeze in winter.    Given the information above, choose from the list below the object entity that exhibits the relation 'taxon rank' with the subject 'water kingfisher'.  Choices: - family  - group  - species  - subfamily  - subspecies
A:
subfamily