Orange-striped emperors Lethrinus obsoletus, copyright Bill & Mark Bell.

Belongs within: Spariformes.

Give us a kiss!
Published 13 November 2007
Lethrinus harak, from Wikimedia.

The fish genus Lethrinus is found in tropical waters of the Indian and western Pacific Oceans, with a single species making an incursion into the eastern Atlantic. The group is commonly known as emperors, though I have heard people here in Australia refer to them as snappers, a confusing piece of terminology for me because they are quite different fish from the one I knew in New Zealand as snapper*. The prominent lips in Lethrinus adults, often a different colour from the surrounding face, have given at least one species the memorable name of “sweetlips”. Carpenter & Allen (1989) listed 26 described species and two unnamed species in the genus. One of these undescribed species was named Lethrinus ravus by Carpenter & Randall (2003).

*If you excuse me, I’m just going to have a little rant about the common names of Southern Hemisphere fishes. As with other animals and plants, British settlers in New Zealand and Australia labelled the fish they found in their new country with the names of fish they had been familiar with back in the Old Country. However, when it came to fish the new immigrants seem to have gone to extraordinary lengths to find Northern Hemisphere analogues, with the result that it becomes difficult to see how they ever found a connection. The New Zealand grayling (now unfortunately extinct) was no relation to the Northern Hemisphere grayling. The New Zealand cod is even less like the original. And as I’ve already indicated, the confusion surrounding the name “snapper” is beyond anyone’s ability to sort out. Rant over—please resume normal service.

Lethrinus nebulosus, from here.

Emperors are all predators but are divisible into three ecological groups (Lo Galbo et al. 2002)—low-bodied stalkers with conical teeth that are active hunters of high-speed invertebrates and small fish, high-bodied benthic feeders with molariform teeth that can feed on shellfish and other hard-shelled invertebrates, and high-bodied species with conical teeth that feed on softer-bodied slow-moving invertebrates. The molecular phylogeny of Lo Galdo et al. (2002) recovered a good correlation between trophic type and phylogeny. The high-bodied conical-tooth form appears to be ancestral, with one species (Lethrinus minatus) sister to all the other species, and one species each low down in the two major clades that the other species fell into. Low body-form and molariform teeth both appeared twice, in each case with one clade containing most of the species showing the novel feature, and a single species appearing to have developed it independently.

Of course, what discussion of tropical reef fishes would be complete without a mention of transexuality? Many species of Lethrinus have been shown to be protogynous hermaphrodites—that is, they reach maturity as females before changing sex at a later date to males (Young & Martin 1982). The mechanism inducing this change in emperors remains unknown. In other protogynous reef fish species, males may maintain harems of females, the largest of which switches sex if the male is removed for whatever reason, but whether emperors have a similar system has not yet been established.

Systematics of Lethrinidae

    |  i. s.: PentapusM58
    |           |--P. caninus (Cuvier 1830) (see below for synonymy)M58
    |           |--P. hellmuthi (Bleeker 1853) [=Heterognathodon hellmuthi]M58
    |           |--P. microdon (Bleeker 1853) [=Heterognathodon microdon]M58
    |           `--P. nemurus (Bleeker 1852) [=Heterognathodon nemurus]M58
    |         Neolethrinus Castelnau 1875S59
    |    |--Monotaxis Bennett 1830 [incl. Sphaerodon Rüppell 1840]CA89
    |    |    `--M. grandoculis (Forskål 1775)CA89 (see below for synonymy)
    |    |--Wattsia Chan & Chilvers 1974CA89
    |    |    `--*W. mossambica (Smith 1957) [=Gnathodentex mossambicus; incl. Gymnocranius olivaceus Formanoir 1961]CA89
    |    |--Gnathodentex Bleeker 1873CA89
    |    |    `--G. aurolineatus (Lacepède 1802) (see below for synonymy)CA89
    |    `--Gymnocranius Klunzinger 1870 [incl. Paradentex Bleeker 1876]CA89
    |         |--G. grandoculis (Valenciennes in Cuvier & Valenciennes 1830)CA89 (see below for synonymy)
    |         |--G. audleyi Ogilby 1916 [incl. G. bitorquatus Cockerell 1916]CA89
    |         |--G. elongatus Senta 1973B03
    |         |--G. euanus (Günther 1879) (see below for synonymy)CA89
    |         |--G. frenatus Bleeker 1873CA89
    |         |--G. griseus (Schlegel in Temminck & Schlegel 1844) (see below for synonymy)CA89
    |         `--G. microdon (Bleeker 1851) [=Dentex microdon]CA89
    `--Lethrinus Cuvier 1829 [incl. Lethrinella Fowler 1904, Lethrinichthys Jordan & Thompson 1912; Lethrininae]CA89
         |--L. nebulosus (Forsskål 1775) (see below for synonymy)CA89
         |--L. amboinensis Bleeker 1854CA89
         |--L. atkinsoni Seale 1909CA89
         |--L. atlanticus Valenciennes in Cuvier & Valenciennes 1830CA89
         |--L. borbonicus Valenciennes in Cuvier & Valenciennes 1830 (see below for synonymy)CA89
         |--L. conchyliatus (Smith 1959) [=Lethrinella conchyliatus; incl. Lethrinus floridus Wheeler 1961]CA89
         |--L. crocineus Smith 1959CA89
         |--L. enigmaticus Smith 1959CA89
         |--L. erythracanthus Valenciennes in Cuvier & Valenciennes 1830 (see below for synonymy)CA89
         |--L. erythropterus Valenciennes in Cuvier & Valenciennes 1830 (see below for synonymy)CA89
         |--L. genivittatus Valenciennes in Cuvier & Valenciennes 1830CA89 (see below for synonymy)
         |--L. haematopterus Temminck & Schlegel 1844 [incl. L. richardsoni Günther 1859]CA89
         |--L. harak (Forsskål 1775) (see below for synonymy)CA89
         |--L. jagorii Peters 1868 (n. d.)CA89
         |--L. laticaudis Alleyne & Macleay 1877 [incl. L. anarhynchus Postel 1965, L. fletus Whitley 1943]CA89
         |--L. lentjan (Lacepède 1802)CA89 (see below for synonymy)
         |--L. mahsena (Forsskål 1775) (see below for synonymy)CA89
         |--L. microdon Valenciennes in Cuvier & Valenciennes 1830CA89 (see below for synonymy)
         |--L. miniatus (Schneider in Bloch & Schneider 1801)CA89 (see below for synonymy)
         |--L. obsoletus (Forsskål 1775)CA89 (see below for synonymy)
         |--L. oculatus Gudger 1929 (n. d.)S59
         |--L. olivaceus Valenciennes in Cuvier & Valenciennes 1830 (see below for synonymy)CA89
         |--L. ornatus Valenciennes in Cuvier & Valenciennes 1830 (see below for synonymy)CA89
         |--L. plebeius Val 1830S59
         |--L. reticulatus Valenciennes in Cuvier & Valenciennes 1830CA89
         |--L. rubrioperculatus Sato 1978CA89
         |--L. semicinctus Valenciennes in Cuvier & Valenciennes 1830 (see below for synonymy)CA89
         |--L. variegatus Valenciennes in Cuvier & Valenciennes 1830CA89 (see below for synonymy)
         |--L. violaceusS59
         `--L. xanthochilus Klunzinger 1870CA89 [=Lethrinella xanthocheilusS59]
Nomina nuda: Lethrinus erythrophthalmus Kittlitz 1858CA89
             Lethrinus lachrymans Savilie-Kent 1893CA89
             Lethrinus margaritifer Saville-Kent 1893CA89
             Lethrinus regius Saville-Kent 1893CA89
             Lethrinus undulosus Monroe 1955CA89
             Lethrinus viridis Saville-Kent 1893CA89

Gnathodentex aurolineatus (Lacepède 1802) [=Sparus aureolineatus, Dentex aurolineatus, Pentapodus aurolineatus, Pentapus aurolineatus; incl. Dentex lycogenis Bennett 1831, Gnathodentex ocumaculatus Herre 1935]CA89

Gymnocranius euanus (Günther 1879) [=Sphaerodon euanus; incl. Monotaxis affinis Whitley 1943, G. japonicus Akazaki 1961]CA89

Gymnocranius grandoculis (Valenciennes in Cuvier & Valenciennes 1830)CA89 [=Cantharus grandoculisCA89; incl. Pentapus curtus Guichenot 1865CA89, Pe. dux Valenciennes 1862CA89, Dentex lethrinoides Bleeker 1851CA89, Gymnocranius lethrinoidesJR10, Paradentex marshalli Whitley 1936CA89, D. rivulatus Rüppell 1838 non Bennett 1835CA89, *Gymnocranius rivulatusCA89, D. robinsoni Gilchrist & Thompson 1908CA89, G. robinsoniC01, G. ruppellii Smith 1941CA89]

Gymnocranius griseus (Schlegel in Temminck & Schlegel 1844) [=Dentex griseus; incl. Lobotes microprion Bleeker 1851, Gymnocranius orbis Fowler 1938]CA89

Lethrinus borbonicus Valenciennes in Cuvier & Valenciennes 1830 [incl. L. bungus Valenciennes 1830, L. ehrenbergii Valenciennes 1830]CA89

Lethrinus erythracanthus Valenciennes in Cuvier & Valenciennes 1830 [incl. L. cinnabarinus Richardson 1843, L. kallopterus Bleeker 1856]CA89

Lethrinus erythropterus Valenciennes in Cuvier & Valenciennes 1830 [incl. L. hypselopterus Bleeker 1873, L. striatus Steindachner 1866]CA89

Lethrinus genivittatus Valenciennes in Cuvier & Valenciennes 1830CA89 [incl. Lethrinus nematacanthus Bleeker 1854CA89, Lethrinella nematacanthaG79, Lethrinichthys nematacanthusM58]

Lethrinus harak (Forsskål 1775) [=Sciaena harak; incl. L. azureus Valenciennes 1830, L. bleekeri Klunzinger 1884, L. bonhamensis Günther 1873, L. johnii Castelnau 1873, L. papuensis Alleyne & Macleay 1877, L. rhodopterus Bleeker 1852]CA89

Lethrinus lentjan (Lacepède 1802)CA89 [=Bodianus lentjanCA89; incl. L. argenteus Valenciennes 1830CA89, L. cinereus Valenciennes 1830CA89, L. cocosensis Bleeker 1854CA89, L. croceopterus Valenciennes 1830CA89, L. flavescens Valenciennes 1830CA89, L. fusciceps Macleay 1878CA89, L. geniguttatus Valenciennes 1830CA89, L. glyphodon Günther 1859CA89, L. leutjanus Valenciennes 1830S59, L. mahsenoides Valenciennes 1830CA89, Pentapodus nubilis Cantor 1849CA89, L. nubilisCA89, L. opercularis Valenciennes 1830CA89, L. punctulatus Macleay 1878CA89, L. virescens Valenciennes 1830CA89]

Lethrinus mahsena (Forsskål 1775) [=Sciaena mahsena; incl. L. abbreviatus Valenciennes 1830, L. caeruleus Valenciennes 1830, L. sanguineus Smith 1955]CA89

Lethrinus microdon Valenciennes in Cuvier & Valenciennes 1830CA89 [=Lethrinella microdonS59; incl. L. acutus Klunzinger 1884CA89, L. elongatus Valenciennes 1830CA89]

Lethrinus miniatus (Schneider in Bloch & Schneider 1801)CA89 [=Sparus miniatusM58, *Lethrinella miniatusS59; incl. Lethrinus amamianus Akazaki 1962CA89, Lethrinus chrysostomus Richardson 1848CA89, Lethrinus imperialis DeVis 1884CA89]

Lethrinus nebulosus (Forsskål 1775) [=Sciaena nebulosa; incl. L. alboguttatus Valenciennes 1830, L. anatarius Richardson 1844, L. aurolineatus Macleay 1883, L. carinatus Weber 1913, L. centurio Valenciennes 1830, Sparus choerorynchus Bloch & Schneider 1801, *L. choerorynchus, L. cyanoxanthus Richardson 1843, L. devisianus Whitley 1929, L. erythrurus Valenciennes 1830, L. esculentus Valenciennes 1830, L. fasciatus Valenciennes 1830, L. fraenatus Valenciennes 1830, L. gothofredi Valenciennes 1830, L. guentheri Bleeker 1873, L. karwa Valenciennes 1830, L. korely Valenciennes 1830, L. maculatus Valenciennes 1830, L. perselectus Whitley 1933, L. scoparius Gilchrist & Thompson 1908]CA89

Lethrinus obsoletus (Forsskål 1775)CA89 [=Sciaena obsoletaCA89, S. ramak Forsskål 1775S59, L. ramakM58; incl. L. cutambi Seale 1909CA89]

Lethrinus olivaceus Valenciennes in Cuvier & Valenciennes 1830 [incl. L. longirostris Playfair & Günther 1866, L. rostratus Valenciennes 1830, L. rostratus specificus Borodin 1932, L. waigiensis Valenciennes 1830, L. xanthopterus Valenciennes 1830]CA89

Lethrinus ornatus Valenciennes in Cuvier & Valenciennes 1830 [incl. L. insulindicus Bleeker 1873, L. xanthotaenia Bleeker 1851]CA89

Lethrinus semicinctus Valenciennes in Cuvier & Valenciennes 1830 [incl. L. moensii Bleeker 1855, L. sordidus Valenciennes 1830]CA89

Lethrinus variegatus Valenciennes in Cuvier & Valenciennes 1830CA89 [=Lethrinella variegatusS59; incl. Lethrinus latifrons Rüppell 1840CA89]

Monotaxis grandoculis (Forskål 1775)CA89 [=Sciaena grandoculisCA89, M. (Sphaerodon) grandoculisM58; incl. Pagrus heterodon Bleeker 1854CA89, M. heterodonJR10, *M. indica Bennett 1830CA89, Lethrinus latidens Valenciennes 1830CA89]

Pentapus caninus (Cuvier 1830) [=Scolopsides caninus; incl. Heterognathodon bifasciatus Meyer 1885, Scolopsis elongatus de Beaufort 1913, Pentapus pleurostictus Duncker & Mohr 1931, Pentapus vittatus Seale 1906, Pentapodus xanthopleura Fowler 1931]M58

*Type species of generic name indicated


[B03] Béarez, P. 2003. Premier signalement de Scolopsis taeniopterus (Nemipteridae) et de Gymnocranius elongatus (Lethrinidae) en Nouvelle-Calédonie. Cybium 27 (1): 61–62.

[C01] Carpenter, K. E. 2001. Lethrinidae. Emperors (emperor snappers). In: Carpenter, K. E., & V. H. Niem (eds) FAO Species Identification Guide for Fishery Purposes. The Living Marine Resources of the Western Central Pacific vol. 5. Bony fishes part 3 (Menidae to Pomacentridae) pp. 3004–3050. Food and Agriculture Organization of the United Nations: Rome.

[CA89] Carpenter, K. E., & G. R. Allen. 1989. FAO Species Catalogue vol. 9. Emperor Fishes and Large-eye Breams of the World (Family Lethrinidae): An annotated and illustrated catalogue of lethrinid species known to date. Food and Agriculture Organization of the United Nations.

Carpenter, K. E., & J. E. Randall. 2003. Lethrinus ravus, a new species of emperor fish (Perciformes: Lethrinidae) from the western Pacific and eastern Indian oceans. Zootaxa 240: 1–8.

[JR10] Jordan, D. S., & R. E. Richardson. 1910. Check-list of the species of fishes known from the Philippine archipelago. Bureau of Printing: Manila.

Lo Galbo, A. M., K. E. Carpenter & D. L. Reed. 2002. Evolution of trophic types in emperor fishes (Lethrinus, Lethrinidae, Percoidei) based on cytochrome b gene sequence variation. Journal of Molecular Evolution 54 (6): 754–762.

[M58] Munro, I. S. R. 1958. The fishes of the New Guinea region: a check-list of the fishes of New Guinea incorporating records of species collected by the Fisheries Survey Vessel “Fairwind” during the years 1948 to 1950. Papua and New Guinea Agricultural Journal 10 (4): 97–369 (reprinted: 1958. Territory of Papua and New Guinea Fisheries Bulletin no. 1).

[S59] Smith, J. L. B. 1959. Fishes of the family Lethrinidae from the western Indian Ocean. Ichthyological Bulletin 17: 285–295.

Young, P. C., & R. B. Martin. 1982. Evidence for protogynous hermaphroditism in some lethrinid fishes. Journal of Fish Biology 21 (4): 475–484.

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