The rufous-backed dwarf kingfisher (''Ceyx rufidorsa'') is a small bird in the kingfisher family Alcedinidae that is found in parts of Maritime Southeast Asia. It was formerly considered to be conspecific with the

black-backed dwarf kingfisher The black-backed dwarf kingfisher (''Ceyx erithaca''), also known as the three-toed kingfisher, is a pocket-sized bird in the family Alcedinidae. It was formerly considered as conspecific with the rufous-backed dwarf kingfisher and together th ...

and together the two taxa were known by the English name "oriental dwarf kingfisher". This tropical kingfisher is easily distinguishable from other birds in its range due to its red bill, yellow-orange underparts, lilac- rufous upperparts, and rufous back. It resides in lowland forests, typically near streams or ponds, where it feeds upon insects, spiders, worms, crabs, fish, frogs, and lizards.

Taxonomy

The rufous-backed dwarf kingfisher was formally described in 1847 by the English naturalist Hugh Edwin Strickland under the current

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''Ceyx rufidorsa''. He specified the type locality as

Malacca Malacca ( ms, Melaka) is a state in Malaysia located in the southern region of the Malay Peninsula, next to the Strait of Malacca. Its capital is Malacca City, dubbed the Historic City, which has been listed as a UNESCO World Heritage Site si ...

at the southern end of the

Malay Peninsula The Malay Peninsula (Malay: ''Semenanjung Tanah Melayu'') is a peninsula in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The area ...

. The specific epithet combines Latin ''rufus'' meaning "rufous" with ''dorsus'' meaning "back". The rufous-backed dwarf kingfisher was formerly considered to be a

colour morph In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the s ...

of the

(''Ceyx erithaca''). The two species complex was known as the "oriental dwarf kingfisher".

Molecular genetic Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the ...

studies have shown that ''Ceyx rufidorsa'' is a distinct taxon and that the polymorphism is the result of ancient

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Intr ...

in which some genes from ''Ceyx erithaca'' were transferred to ''Ceyx rufidorsa'' around 140,000 years ago. Five

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

are recognised: * ''C. r. rufidorsa'' Strickland, 1847 – south

Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

, Lubang, Bangka and Belitung (east of south

), Java, Borneo (except northeast) and

Lesser Sunda Islands The Lesser Sunda Islands or nowadays known as Nusa Tenggara Islands ( id, Kepulauan Nusa Tenggara, formerly ) are an archipelago in Maritime Southeast Asia, north of Australia. Together with the Greater Sunda Islands to the west they make up t ...

Flores Flores is one of the Lesser Sunda Islands, a group of islands in the eastern half of Indonesia. Including the Komodo Islands off its west coast (but excluding the Solor Archipelago to the east of Flores), the land area is 15,530.58 km2, and th ...

and Pantar. * ''C. r. motleyi''

Chasen ChaSen is a morphological parser for the Japanese language. This tool for analyzing morphemes was developed at the Matsumoto laboratory, Nara Institute of Science and Technology. See also * MeCab MeCab is an open-source text segmentation lib ...

& Kloss, 1929 – northeast Borneo ( Sabah to East

Kalimantan Kalimantan () is the Indonesian portion of the island of Borneo. It constitutes 73% of the island's area. The non-Indonesian parts of Borneo are Brunei and East Malaysia. In Indonesia, "Kalimantan" refers to the whole island of Borneo. In 2019, ...

) and adjacent northern offshore islands * ''C. r. captus''

Ripley Ripley may refer to: People and characters * Ripley (name) * ''Ripley'', the test mannequin aboard the first International Space Station space station Dragon 2 space test flight Crew Dragon Demo-1 * Ellen Ripley, a fictional character from the Ali ...

, 1941 – Nias (west of north

) * ''C. r. jungei'' Ripley, 1942 –

Batu Islands The Batu Islands are an archipelago of Indonesia located in the Indian Ocean, off the west coast of Sumatra, between Nias and Siberut. The three primary islands, of approximately equal size, are Pini, Tanahmasa, and Tanahbala. There are seventy ...

and Simeulue (west of north

) * ''C. r. vargasi'' Manuel, 1939 – Lubang, Mindoro (northwest, southwest Philippines),

References

{{Taxonbar, from=Q31771 Rufous-backed dwarf kingfisher Rufous-backed dwarf kingfisher Birds of Southeast Asia Rufous-backed dwarf kingfisher Rufous-backed dwarf kingfisher