Chaetodon

Chaetodon is a tropical fish genus in the family Chaetodontidae. Like their relatives, they are known as "butterflyfish". This genus is by far the largest among the Chaetodontidae, with about 90 living species included here,^[1] though most might warrant recognition as distinct genera.

Chaetodon Temporal range: 33.9–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Early Oligocene – Recent
Foureye butterflyfish (Chaetodon capistratus)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Acanthuriformes
Family:	Chaetodontidae
Genus:	Chaetodon Linnaeus, 1758
Type species
Chaetodon capistratus Linnaeus, 1758
Subgenera
List Chaetodon Linnaeus, 1758 "Citharoedus" Kaup, 1860 (non Herrmannsen, 1847: preoccupied) Corallochaetodon Burgess, 1978 Discochaetodon Nalbant, 1971 Exornator Nalbant, 1971 Gonochaetodon Bleeker, 1876 Lepidochaetodon Bleeker, 1876 Megaprotodon Guichenot, 1848 Rabdophorus Swainson, 1839 Rhombochaetodon Burgess, 1978 (disputed) Tetrachaetodon Weber & Beaufort, 1936 and see text
Synonyms
List Aspilurochaetodon Mauge & Bauchot, 1984 Burgessius Mauge & Bauchot, 1984 Chaetodontops Bleeker, 1876 Heterochaetodon Mauge & Bauchot, 1984 Roaops Mauge & Bauchot, 1984 Tifia Jordan in Jordan & Jordan, 1922

Taxonomy

Proposed subgenera

Several subgenera have been proposed for splitting out of this group. It is becoming clear how the genus might be split up, with a range^[2][3] of DNA sequence data in large parts agreeing with S.D. Blum's landmark 1988 phylogenetic assessment of osteology.^[4]

Basically, a core group around the type species Chaetodon capistratus would remain in Chaetodon, while maybe four clades would be split off. These could use the names Lepidochaetodon, Megaprotodon and Rabdophorus, and there is one unnamed group containing the three-banded butterflyfish (C. robustus) and its relatives. But the monophyly of the Lepidochaetodon group is not fully established; it is both unclear whether Rhombochaetodon is a lineage distinct from Exornator, and whether Lepidochaetodon is indeed closer to these than to any other Chaetodon, particularly to some lineages otherwise placed in Megaprotodon.^[2]

Prognathodes, for some time contained in Chaetodon, is worthy of recognition as full genus, as is Roa.^[5]

Historically, more distantly related fish were placed in Chaetodon too, for resembling them in details – e.g. the common scat Scatophagus argus, which has a similar shape and size, as well as armored larvae like the Chaetodontidae – or simply because they are colorful, smallish, and unusual-looking – e.g. the quite unrelated paradise fish, as C. chinensis.

The classification proposed in Fessler and Westneat is based on the species of Chaetodon they sampled and these sorted into the following clades:^[2]

Clades

Clade 1	Clade 2	Clade 3	Clade 4
C. robustus C. hoefleri	C. kleini C. unimaculatus C. fremblii C. burgessi C. xanthurus C. paucifasciatus C. mertensi C. quadrimaculatus C. citrinellus C. multicinctus C. punctatofasciatus C. pelewensis C. sedentarius C. dolosus C. miliaris C. guentheri	C. austriacus C. trifasciatus C. ornatissimus C. reticularis C. meyeri C. larvatus C. baronessa C. trifascialis C. rainfordi C. octofasciatus C. bennetti C. plebius C. speculum C. zanzibarensis	C. austriacus C. trifasciatus C. ornatissimus C. reticularis C. meyeri C. larvatus C. baronessa C. trifascialis C. rainfordi C. octofasciatus C. bennetti C. plebius C. speculum C. zanzibarensis

Extant species

There are currently 87 recognized species in this genus:^[6]

Chaetodon sensu stricto

Species	Common name	Image
Chaetodon capistratus Linnaeus, 1758	Foureye butterflyfish
Chaetodon ocellatus Bloch, 1787	Spotfin butterflyfish
Chaetodon striatus Linnaeus, 1758	Banded butterflyfish

C. robustus group

Species	Common name	Image
Chaetodon hoefleri Steindachner, 1881	Four-banded butterflyfish
Chaetodon robustus Günther, 1860	Three-banded butterflyfish

Lepidochaetodon group

Subgenus Exornator

Species	Common name
Chaetodon citrinellus G. Cuvier, 1831	Speckled butterflyfish, Citron butterflyfish
Chaetodon dolosus C. G. E. Ahl, 1923	African butterflyfish
Chaetodon guentheri C. G. E. Ahl, 1923	Crochet butterflyfish
Chaetodon guttatissimus E. T. Bennett, 1833	Peppered butterflyfish
Chaetodon miliaris Quoy & Gaimard, 1825	Millet butterflyfish
Chaetodon multicinctus A. Garrett, 1863	Pebbled butterflyfish
Chaetodon pelewensis Kner, 1868	Sunset butterflyfish
Chaetodon punctatofasciatus G. Cuvier, 1831	Spotband butterflyfish
Chaetodon quadrimaculatus J. E. Gray, 1831	Fourspot butterflyfish
Chaetodon sedentarius Poey, 1860	Reef butterflyfish

*Nota bene: including Burgessius, Heterochaetodon and possibly Rhombochaetodon; tentatively placed here.

Subgenus Lepidochaetodon

Species	Common name
Chaetodon daedalma D. S. Jordan & Fowler, 1902	Wrought-iron butterflyfish
Chaetodon interruptus C. G. E. Ahl, 1923	Yellow teardrop butterflyfish
Chaetodon kleinii Bloch, 1790	Sunburst butterflyfish, black-lipped butterflyfish, Klein's butterflyfish
Chaetodon litus J. E. Randall & D. K. Caldwell, 1973	Easter Island butterflyfish
Chaetodon nippon Steindachner & Döderlein (de), 1883	Japanese butterflyfish
Chaetodon smithi J. E. Randall, 1975	Smith's butterflyfish
Chaetodon trichrous Günther, 1874	Tahiti butterflyfish
Chaetodon unimaculatus Bloch, 1787	Teardrop butterflyfish

*Nota bene: including Tifia. C. daedalma, C. litus, C. nippon, and C. smithi are tentatively placed here.

Subgenus Rhombochaetodon

Species	Common name	Images
Chaetodon argentatus H. M. Smith & Radcliffe, 1911	Asian butterflyfish
Chaetodon blackburnii Desjardins, 1836	Brownburnie
Chaetodon burgessi G. R. Allen & Starck, 1973	Burgess' butterflyfish
Chaetodon declivis J. E. Randall, 1975	Marquesas butterflyfish
Chaetodon flavocoronatus R. F. Myers, 1980	Yellow-crowned butterflyfish
Chaetodon fremblii E. T. Bennett	Blue-striped butterflyfish
Chaetodon madagaskariensis C. G. E. Ahl, 1923	Seychelles butterflyfish
Chaetodon mertensii G. Cuvier, 1831	Atoll butterflyfish
Chaetodon mitratus Günther, 1860	Indian butterflyfish
Chaetodon paucifasciatus C. G. E. Ahl, 1923	Eritrean butterflyfish, crown butterflyfish
Chaetodon tinkeri L. P. Schultz, 1951	Hawaiian butterflyfish
Chaetodon xanthurus Bleeker, 1857	Pearlscale butterflyfish, Philippines chevron butterflyfish, yellow-tailed butterflyfish

Nota bene: including Roaops, might belong in Exornator; tentatively placed here. C. blackburnii, C. declivis, C. flavocoronatus, C. mitratus, and C. tinkeri tentatively placed here.

Megaprotodon group

Subgenus "Citharoedus"

Species	Common name	Image
Chaetodon meyeri Bloch & J. G. Schneider, 1801	Scrawled butterflyfish
Chaetodon ornatissimus G. Cuvier, 1831	Ornate butterflyfish
Chaetodon reticulatus G. Cuvier, 1831	Mailed butterflyfish

Nota bene: tentatively placed here.

Subgenus Corallochaetodon

Species	Common name	Image
Chaetodon austriacus Rüppell, 1836	Blacktail butterflyfish, exquisite butterflyfish
Chaetodon lunulatus Quoy & Gaimard, 1825	Redfin butterflyfish, oval butterflyfish
Chaetodon melapterus Guichenot, 1863	Arabian butterflyfish
Chaetodon trifasciatus M. Park, 1797	Indian redfin butterflyfish, melon butterflyfish

Nota bene: tentatively placed here.

Subgenus Discochaetodon

Species	Common name	Image
Chaetodon aureofasciatus W. J. Macleay, 1878	Golden butterflyfish
Chaetodon octofasciatus Bloch, 1787	Eightband butterflyfish
Chaetodon rainfordi McCulloch, 1923	Rainford's butterflyfish
Chaetodon tricinctus Waite, 1901	Three-striped butterflyfish

Nota bene: C. tricinctus tentatively placed here in Discochaetodon.

Subgenus Gonochaetodon

Species	Common name	Image
Chaetodon baronessa G. Cuvier, 1829	Eastern triangle butterflyfish
Chaetodon larvatus G. Cuvier, 1831	Hooded butterflyfish
Chaetodon triangulum G. Cuvier, 1831	Triangle butterflyfish

Nota bene: tentatively placed here.

Subgenus Megaprotodon

Species	Common name	Image
Chaetodon trifascialis Quoy & Gaimard, 1825	Chevron butterflyfish, triangulate butterflyfish, V-lined butterflyfish

Subgenus Tetrachaetodon

Species	Common name	Image
Chaetodon andamanensis Kuiter & Debelius (de), 1999	Andaman butterflyfish
Chaetodon bennetti G. Cuvier, 1831	Bluelashed butterflyfish
Chaetodon plebeius G. Cuvier, 1831	Blue-blotched butterflyfish
Chaetodon speculum G. Cuvier, 1831	Mirror butterflyfish
Chaetodon zanzibarensis Playfair (fr), 1867	Zanzibar butterflyfish

Nota bene: C. andamanensis is tentatively placed here in Tetrachaetodon.

Rabdophorus group

Species		Common name	Image
Aspilurochaetodon	Chaetodon gardineri Norman, 1939	Gardner's butterflyfish
	Chaetodon leucopleura Playfair, 1867	Somali butterflyfish
	Chaetodon selene Bleeker, 1853	Yellow-dotted butterflyfish
Chaetodon adiergastos Seale, 1910		Philippine butterflyfish, Panda butterflyfish
Chaetodon auriga Forsskål, 1775		Threadfin butterflyfish
Chaetodon auripes D. S. Jordan & Snyder, 1901		Oriental butterflyfish
Chaetodon collare Bloch, 1787		Redtail butterflyfish, Pakistani butterflyfish
Chaetodon decussatus G. Cuvier, 1829		Indian vagabond butterflyfish
Chaetodon ephippium G. Cuvier, 1831		Saddle butterflyfish
Chaetodon falcula Bloch, 1795		Blackwedged butterflyfish
Chaetodon fasciatus Forsskål, 1775		Red Sea raccoon butterflyfish, diagonal butterflyfish
Chaetodon flavirostris Günther, 1874		Black butterflyfish
Chaetodon lineolatus G. Cuvier, 1831		Lined butterflyfish
Chaetodon lunula (Lacépède, 1802)		Raccoon butterflyfish, crescent-masked butterflyfish, lunule butterflyfish
Chaetodon melannotus Bloch & J. G. Schneider, 1801		Blackback butterflyfish
Chaetodon mesoleucos Forsskål, 1775		White-faced butterflyfish
Chaetodon nigropunctatus Sauvage, 1880		Black-spotted butterflyfish
Chaetodon ocellicaudus G. Cuvier, 1831		Spot-tail butterflyfish
Chaetodon oxycephalus Bleeker, 1853		Spot-naped butterflyfish
Chaetodon pictus Forsskål, 1775		Horseshoe butterflyfish
Chaetodon rafflesii Anonymous [Bennett], 1830		Latticed butterflyfish
Chaetodon semeion Bleeker, 1855		Dotted butterflyfish
Chaetodon semilarvatus G. Cuvier, 1831		Bluecheek butterflyfish
Chaetodon ulietensis G. Cuvier, 1831		Pacific double-saddle butterflyfish, false falcula butterflyfish
Chaetodon vagabundus Linnaeus, 1758		Vagabond butterflyfish
Chaetodon wiebeli Kaup, 1863		Hong Kong butterflyfish
Chaetodon xanthocephalus E. T. Bennett, 1833		Yellowhead butterflyfish

Nota bene: Including Aspilurochaetodon and Chaetodontops. C. auripes, C. gardineri, C. leucopleura, C. nigropunctatus, and C. xanthocephalus are tentatively placed in this group.

Incertae sedis

Species	Common name
Chaetodon assarius Waite, 1905	West Australian butterflyfish
Chaetodon dialeucos Salm & Mee, 1989	Oman butterflyfish
Chaetodon humeralis Günther, 1860	Threebanded butterflyfish
Chaetodon marleyi Regan, 1921	Doublesash butterflyfish
Chaetodon sanctaehelenae Günther, 1868	Saint Helena butterflyfish

Nota bene: most are probably either Chaetodon sensu stricto or C. robustus group.

Fossil species

The following fossil species are known:^[7]

• Subgenus †Arambourgchaetodon^[8]
  • †Chaetodon ficheuri Arambourg, 1927 (Late Miocene of Algeria)
• Subgenus †Blumchaetodon
  • †Chaetodon wattsi Marramà, Giusberti & Carnevale, 2022 (Early Oligocene of Italy)

The species Chaetodon penniger Bogachev, 1964 from the late Oligocene of Azerbaijan cannot be confidently assigned to this genus due to the incompleteness of the fossil.^[7]

Evolution & fossil record

Fossil of Chaetodon species

The earliest confirmed specimens of Chaetodon are from Early Oligocene-aged coral reef deposits of Italy, belonging to the extinct species Chaetodon wattsi. This fossil is roughly concurrent when the family is thought to have radiated into its modern genus diversity. Indeterminate Chaetodon fossil specimens (including both articulated specimens and otoliths) referred to Chaetodon hoefleri are known from the Late Oligocene of Slovenia and the mid-late Miocene of Poland.^[7]

As it is not easy to distinguish this genus from close relatives, it may be that some Oligocene fossils are actually of other Chaetodontidae. The fossil record of this family is scant, with only Chelmon (or some similar genus like Chelmonops or Coradion) being known from Miocene remains. As even crude molecular clocks suggest that the ancestors of the Chaetodon and the Chelmops lineage diverged in the Late Eocene already, nothing more can be said without new fossils being discovered.^[9][10]