Ixos
Encyclopedia
Ixos is a songbird
genus
in the bulbul
family
, Pycnonotidae. It provisionally contains the following species
:
is placed in Ixos, but in fact it is better separated in the monotypic
genus Microscelis. The Philippine Bulbul
is sometimes placed in Ixos but otherwise (and probably more appropriately) in Hypsipetes
, where the Sulphur-bellied, Zamboanga and Streak-breasted Bulbuls might also belong.
The Mountain Bulbul
and Sunda Bulbul
– formerly H. mcclellandii and H. virescens – are provisionally placed in Ixos until the genus limits in bulbuls are firmly established. They are often included in Hypsipetes but this is an old error that was promoted in modern times by the Sibley taxonomy. In fact, I. virescens is the type species
of Ixos, and though some sources advocate a complete merger of the two genera – and even the entire "Hypsipetes group" of bulbuls, which also includes Hemixos
, Iole
, Microscelis and Tricholestes –, being the oldest genus name Ixos would apply to all of them, rather than Hypsipetes as is often believed.
The most drastic course hardly appropriate however, since Alophoixus
and Setornis cannot be excluded from the "Hypsipetes group", and an all-out merge would turn the resultant "genus" Ixos into an ill-defined "wastebin taxon
". The erroneous inclusion of I. virescens in Hypsipetes has caused the Nicobar Bulbul
to be listed under its invalid junior synonym H. nicobariensis rather than the valid names H. virescens or I. nicobariensis.
The Streaked Bulbul, meanwhile, seems to be closer to Hemixos
and perhaps Iole
and maybe the Hook-billed Bulbul
(Setornis criniger) than to Hypsipetes. Thus, given the lack of study of the Sunda Bulbul's affiliations, Ixos might eventually be reduced to the core group around I. virescens and kept well distinct from Hypsipetes. Or it may be that some species (such as I. malaccensis) are be split off into a distinct genus (for which no scientific name exists yet), while Hypsipetes is merged into the core group of Ixos.
Songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
in the bulbul
Bulbul
Bulbuls are a family, Pycnonotidae, of medium-sized passerine songbirds. Many forest species are known as greenbuls. The family is distributed across most of Africa and into the Middle East, tropical Asia to Indonesia, and north as far as Japan. A few insular species occur on the tropical islands...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, Pycnonotidae. It provisionally contains the following species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
:
- Yellowish BulbulYellowish BulbulThe Yellowish Bulbul is a species of songbird in the Pycnonotidae family. The scientific name commemorates British colonial administrator and zoological collector Alfred Hart Everett.-Distribution and habitat:...
, Ixos everetti - Streaked BulbulStreaked BulbulThe Streaked Bulbul is a songbird species in the bulbul family . Depending on whether it is or isn't a particularly close relative of the type species of the genus Ixos, the Sunda Bulbul or Green-winged Bulbul , it might belong in a new genus.What is presently known is that some Ixos species are...
, Ixos malaccensis - Sulphur-bellied BulbulSulphur-bellied BulbulThe Sulphur-bellied Bulbul is a songbird species in the bulbul family .It is one of the species of Ixos that might warrant inclusion in the genus Hypsipetes – as long as this is kept separate from Ixos – as it may be a close relative of the Philippine Bulbul The Sulphur-bellied Bulbul...
, Ixos palawanensis (might belong in Hypsipetes) - Zamboanga BulbulZamboanga BulbulThe Zamboanga Bulbul is a songbird species in the bulbul family .It is one of the species of Ixos that might warrant inclusion in the genus Hypsipetes – as long as this is kept separate from Ixos – as it may be a close relative of the Philippine Bulbul The Zamboanga Bulbul (Ixos...
, Ixos rufigularis (might belong in Hypsipetes) - Streak-breasted BulbulStreak-breasted BulbulThe Streak-breasted Bulbul or Mottle-breasted Bulbul is a songbird species in the bulbul family ....
or Mottle-breasted Bulbul, Ixos siquijorensis (might belong in Hypsipetes) - Mountain BulbulMountain BulbulThe Mountain Bulbul is a songbird species in the bulbul family . It is often placed in Hypsipetes, but seems to be closer to the type species of the genus Ixos, the Sunda Bulbul or Green-winged Bulbul...
, Ixos mcclellandii (provisionally placed here) - Sunda BulbulSunda BulbulThe Sunda Bulbul or Green-winged Bulbul is a songbird species in the bulbul family . It is the type species of the genus Ixos....
, Ixos virescens (type speciesType speciesIn biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
)
Systematics and taxonomy
The genus as traditionally delimited is not monophyletic; the Brown-eared BulbulBrown-eared Bulbul
The Brown-eared Bulbul is a medium-sized bulbul which is found from the Russian Far East , northeastern China, the Korean Peninsula, and Japan, south to Taiwan and the Babuyan and Batanes island chains in the north of the Philippines, occasionally being found in Luzon...
is placed in Ixos, but in fact it is better separated in the monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus Microscelis. The Philippine Bulbul
Philippine Bulbul
The Philippine Bulbul is a songbird species in the bulbul family . It is often placed in the genus Ixos, but is better retained in Hypsipetes as long as this is not entirely merged into Ixos, as it is quite closely related to the type species of Hypsipetes, the Black Bulbul The Philippine Bulbul...
is sometimes placed in Ixos but otherwise (and probably more appropriately) in Hypsipetes
Hypsipetes
Hypsipetes is a genus of bulbuls, songbirds in the family Pycnonotidae. Most of its species birds occur in tropical forests around the Indian Ocean. But while the genus is quite diverse in the Madagascar region at the western end of its range it does not reach the African mainland.Most Hypsipetes...
, where the Sulphur-bellied, Zamboanga and Streak-breasted Bulbuls might also belong.
The Mountain Bulbul
Mountain Bulbul
The Mountain Bulbul is a songbird species in the bulbul family . It is often placed in Hypsipetes, but seems to be closer to the type species of the genus Ixos, the Sunda Bulbul or Green-winged Bulbul...
and Sunda Bulbul
Sunda Bulbul
The Sunda Bulbul or Green-winged Bulbul is a songbird species in the bulbul family . It is the type species of the genus Ixos....
– formerly H. mcclellandii and H. virescens – are provisionally placed in Ixos until the genus limits in bulbuls are firmly established. They are often included in Hypsipetes but this is an old error that was promoted in modern times by the Sibley taxonomy. In fact, I. virescens is the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of Ixos, and though some sources advocate a complete merger of the two genera – and even the entire "Hypsipetes group" of bulbuls, which also includes Hemixos
Hemixos
Hemixos is a songbird genus in the bulbul family, Pycnonotidae. Established by Edward Blyth in 1845 for the newly-discovered Ashy Bulbul Hemixos is a songbird genus in the bulbul family, Pycnonotidae. Established by Edward Blyth in 1845 for the newly-discovered Ashy Bulbul Hemixos is a songbird...
, Iole
Iole (genus)
Iole is a genus of bulbuls, songbirds in the family Pycnonotidae. They are native to tropical eastern Asia, from India to China and south through Southeast Asia to northern Indonesia.It includes the following species:* Olive Bulbul, Iole virescens...
, Microscelis and Tricholestes –, being the oldest genus name Ixos would apply to all of them, rather than Hypsipetes as is often believed.
The most drastic course hardly appropriate however, since Alophoixus
Alophoixus
Alophoixus is a genus of songbird in the Pycnonotidae family. All the species occur in southeast Asia.It contains the following species:* Finsch's Bulbul * White-throated Bulbul...
and Setornis cannot be excluded from the "Hypsipetes group", and an all-out merge would turn the resultant "genus" Ixos into an ill-defined "wastebin taxon
Wastebin taxon
Wastebasket taxon is a term used in some taxonomic circles to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined by their lack of one or more distinct character states or by their not belonging to one or more other taxa...
". The erroneous inclusion of I. virescens in Hypsipetes has caused the Nicobar Bulbul
Nicobar Bulbul
Found only on the Nicobar Islands of India, the Nicobar Bulbul is a songbird species in the bulbul family . Its scientific name is Hypsipetes virescens as long as Ixos is recognized as a distinct genus....
to be listed under its invalid junior synonym H. nicobariensis rather than the valid names H. virescens or I. nicobariensis.
The Streaked Bulbul, meanwhile, seems to be closer to Hemixos
Hemixos
Hemixos is a songbird genus in the bulbul family, Pycnonotidae. Established by Edward Blyth in 1845 for the newly-discovered Ashy Bulbul Hemixos is a songbird genus in the bulbul family, Pycnonotidae. Established by Edward Blyth in 1845 for the newly-discovered Ashy Bulbul Hemixos is a songbird...
and perhaps Iole
Iole (genus)
Iole is a genus of bulbuls, songbirds in the family Pycnonotidae. They are native to tropical eastern Asia, from India to China and south through Southeast Asia to northern Indonesia.It includes the following species:* Olive Bulbul, Iole virescens...
and maybe the Hook-billed Bulbul
Hook-billed Bulbul
The Hook-billed Bulbul is a species of songbird in the Pycnonotidae family. It is monotypic within the genus Setornis.It is found in Brunei, Indonesia, and Malaysia....
(Setornis criniger) than to Hypsipetes. Thus, given the lack of study of the Sunda Bulbul's affiliations, Ixos might eventually be reduced to the core group around I. virescens and kept well distinct from Hypsipetes. Or it may be that some species (such as I. malaccensis) are be split off into a distinct genus (for which no scientific name exists yet), while Hypsipetes is merged into the core group of Ixos.