Chaetodon is a tropical fish genus in the familyChaetodontidae. 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.
Species
There are currently 87 recognized species in this genus:[2]
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[3][4] of DNA sequence data in large parts agreeing with S.D. Blum's landmark 1988 phylogenetic assessment of osteology.[5]
Basically, a core group around the type speciesChaetodon 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.[3]
Prognathodes, for some time contained in Chaetodon, is worthy of recognition as full genus, as is Roa.[6]
Historically, more distantly related fish were placed in Chaetodon too, for resembling them in details – e.g. the common scatScatophagus 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:[3]
Clade 1
Chaetodon robustus
Chaetodon hoefleri
Clade 2
Chaetodon kleini
Chaetodon unimaculatus
Chaetodon fremblii
Chaetodon burgessi
Chaetodon xanthurus
Chaetodon paucifasciatus
Chaetodon mertensi
Chaetodon quadrimaculatus
Chaetodon citrinellus
Chaetodon multicinctus
Chaetodon punctatofasciatus
Chaetodon pelewensis
Chaetodon sedentarius
Chaetodon dolosus
Chaetodon miliaris
Chaetodon guentheri
Clade 3
Chaetodon austriacus
Chaetodon trifasciatus
Chaetodon ornatissimus
Chaetodon reticularis
Chaetodon meyeri
Chaetodon larvatus
Chaetodon baronessa
Chaetodon trifascialis
Chaetodon rainfordi
Chaetodon octofasciatus
Chaetodon bennetti
Chaetodon plebius
Chaetodon speculum
Chaetodon zanzibarensis
Clade 4
Chaetodon ocellatus
Chaetodon capistratus
Chaetodon striatus
Chaetodon semeion
Chaetodon ephippium
Chaetodon selene
Chaetodon melannotus
Chaetodon ocellicaudus
Chaetodon rafflesi
Chaetodon auriga
Chaetodon vagabundus
Chaetodon collare
Chaetodon adiergastos
Chaetodon fasciatus
Chaetodon lunula
Chaetodon semilarvatus
Chaetodon lineolatus
Chaetodon oxycephalus
Chaetodon falcula
Chaetodon ulietensis
Fossil record
Fossil of Chaetodon species
The oldest fossils that are usually assigned to Chaetodon date from the late Oligocene, about 25 million years ago. But since it is not easy to distinguish this genus from close relatives, it may be that the Oligocene fossils are actually of other Chaetodontidae. The fossil record of this family is scant indeed, 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.[7][8]
^ abcFessler, Jennifer L.; Westneat, Mark W (2007). "Molecular phylogenetics of the butterflyfishes (Chaetodontidae): Taxonomy and biogeography of a global coral reef fish family". Molecular Phylogenetics and Evolution. 45 (1): 50–68. doi:10.1016/j.ympev.2007.05.018.
^Kuiter, R. H. 2004. Description of a new species of butterflyfish, Roa australis, from northwestern Australia (Pisces: Perciformes: Chaetodontidae). Records of the Australian Museum v. 56 (no. 2): 167-171.
Hsu, Kui-Ching; Chen, Jeng-Ping & Shao, Kwang-Tsao (2007): Molecular phylogeny of Chaetodon (Teleostei: Chaetodontidae) in the Indo-West Pacific: evolution in geminate species pairs and species groups. Raffles Bulletin of ZoologySupplement 14: 77-86. PDF fulltext
Sepkoski, Jack (2002): [Chaetodon]. In: A compendium of fossil marine animal genera. Bulletins of American Paleontology364: 560. HTML database excerpt
