The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family of benthic coastal marine fish historically classified in the order Perciformes, although the 5th edition of Fishes of the World places the family in the Spariformes. The smelt-whitings inhabit a wide region covering much of the Indo-Pacific, from the west coast of Africa east to Japan and south to Australia. The family comprises only five genera and 35 species, of which a number are dubious, with the last major revision of the family in 1992 unable to confirm the validity of a number of species. They are elongated, slightly compressed fish, often light brown to silver in colour, with a variety of markings and patterns on their upper bodies. The Sillaginidae are not related to a number of fishes commonly called 'whiting' in the Northern Hemisphere, including the fish originally called whiting, Merlangius merlangus.
The smelt-whitings are mostly inshore fishes that inhabit sandy, silty, and muddy substrates on both low- and high-energy environments ranging from protected tidal flats and estuaries to surf zones. A few species predominantly live offshore on deep sand shoals and reefs, although the larvae and juvenile phases of most species return to inshore grounds, where they spend the first few years of their lives. Smelt-whitings are benthic carnivores that prey predominantly on polychaetes, a variety of crustaceans, molluscs, and to a lesser extent echinoderms and fish, feeding by detecting vibrations emitted by their prey.
The family is highly important to fisheries throughout the Indo-Pacific, with species such as the northern whiting, Japanese whiting, and King George whiting forming the basis of major fisheries throughout their range. Many species are also of major importance to small subsistence fisheries, while others are little more than occasional bycatch. Smelt-whitings are caught by a number of methods, including trawling, seine nets, and cast nets. In Australia and Japan in particular, members of the family are often highly sought by recreational fishermen who also seek the fish for their prized flesh.
Taxonomy
The first species of sillaginid to be scientifically described was Sillago sihama, by Peter Forsskål in 1775, who initially referred the species to a genus of hardyhead, Atherina. It was not until 1817 that the type genus Sillago was created by Georges Cuvier based on his newly described species Sillago acuta, which was later found to be a junior synonym of S. sihama and subsequently discarded. Cuvier continued to describe species of sillaginid with the publishing of his ichthyological work Histoire Naturelle des Poissons with Achille Valenciennes in 1829, also erecting the genus Sillaginodes in this work. The species Cheilodipterus panijus was named in 1822 by Francis Buchanan-Hamilton and was subsequently reexamined by Theodore Gill in 1861, leading to the creation of the monotypic genus Sillaginopsis. John Richardson was the first to propose that Sillago, the only genus of sillaginid then recognised, be assigned to their own taxonomic family, "Sillaginidae" (used interchangeably with 'Sillaginoidae'), at a meeting of the British Association for the Advancement of Science. There were, however, many differing opinions on the relationships of the "sillaginoids", leading to the naturalists of the day continually revising the position of the five genera, placing in them in a number of families. The first review of the sillaginid fishes was Gill's 1861 work "Synopsis of the sillaginoids", in which the name "Sillaginidae" was popularized and expanded on to include Sillaginodes and Sillaginopsis, however the debate on the placement of the family remained controversial.
In the years after Gill's paper was published, over 30 'new' species of sillaginids were reported and scientifically described, many of which were synonyms of previously described species, with similarity between species, as well as minor geographical variation confounding taxonomists. In 1985, Roland McKay of the Queensland Museum published a comprehensive review of the family to resolve these relationships, although a number of species are still listed as doubtful, with McKay unable to locate the holotypes. Along with the review of previously described species, McKay described an additional seven species, a number of which he described as subspecies. After this 1985 paper, additional specimens came to light, proving that all the subspecies he had identified were individual species. In 1992, McKay published a synopsis of the Sillaginidae for the FAO, in which he elevated these subspecies to full species status.
The name "Sillaginidae" was derived from Cuvier's Sillago, which itself takes its name from a locality in Australia, possibly Sillago reef off the coast of Queensland. The term "sillago" is derived from the Greek term syllego, which means "to meet".
Classification The following is a comprehensive list of the 35 known extant species of sillaginids, with a number of the species still in doubt due to the loss of the holotype specimen. This classification follows Fishbase, which itself is based on McKay's last revision of the family.
Family SILLAGINIDAE Genus Sillaginodes T.N. Gill, 1861 Sillaginodes punctatus (Cuvier, 1829) (King George whiting) Genus Sillaginopodys Fowler, 1933 Sillaginopodys chondropus (Bleeker, 1849) (Club-foot whiting) Genus Sillaginops Kaga, 2013 Sillaginops macrolepis (Bleeker, 1858) (Large-scale whiting) Genus Sillaginopsis Sillaginopsis panijus (Hamilton, 1822) (Gangetic whiting) Genus Sillago (Cuvier, 1816) Sillago aeolus D. S. Jordan & Evermann, 1902 (Oriental sillago) Sillago analis Whitley, 1943 (Golden-lined sillago) Sillago arabica McKay & McCarthy, 1989 (Arabian sillago) Sillago argentifasciata C. Martin & H. R. Montalban, 1935 (Silver-banded sillago) Sillago asiatica McKay, 1982 (Asian sillago) Sillago attenuata McKay, 1985 (Slender sillago) Sillago bassensis G. Cuvier, 1829 (Western school sillago) Sillago boutani Pellegrin, 1905 (Boutan's sillago) Sillago burrus Richardson, 1842 (Western trumpeter sillago) Sillago caudicula Kaga, Imamura, Nakaya, 2010 Sillago ciliata G. Cuvier, 1829 (Sand sillago) Sillago erythraea G. Cuvier, 1829 Sillago flindersi McKay, 1985 (Flinders' sillago) Sillago indica McKay, Dutt & Sujatha, 1985 (Indian sillago) Sillago ingenuua McKay, 1985 (Bay sillago) Sillago intermedius Wongratana, 1977 (Intermediate sillago) Sillago japonica Temminck & Schlegel, 1843 (Japanese sillago) Sillago lutea McKay, 1985 (Mud sillago) Sillago maculata Quoy & Gaimard, 1824 (Trumpeter sillago) Sillago megacephalus S. Y. Lin, 1933 (Large-headed sillago) Sillago microps McKay, 1985 (Small-eyed sillago) Sillago muktijoddhai Gao & Saha, 2022 Sillago nierstraszi Hardenberg, 1941 (Rough sillago) Sillago nigrofasciata J. G. Xiao, Zheng-Sen Yu, Na Song & T. X. Gao, 2021 Sillago parvisquamis T. N. Gill] 1861 (Small-scale sillago) Sillago robusta Stead, 1908 (Stout sillago) Sillago schomburgkii W. K. H. Peters, 1864 (Yellowfin sillago) Sillago sihama Forsskål, 1775 (Silver sillago) Sillago sinica T. X. Gao, D. P. Ji, Y. S. Xiao, T. Q. Xue, Yanagimoto & Setoguma, 2011 (Chinese sillago) Sillago soringa Dutt & Sujatha, 1982 (Soringa sillago) Sillago suezensis Golani, R. Fricke & Tikochinski, 2013 Sillago vincenti McKay, 1980 (Vincent's sillago) Sillago vittata McKay, 1985 (Banded sillago)
Evolution A number of sillaginids have been identified from the fossil record, with the lower Eocene marking the first appearance of the family. The family is thought to have evolved in the Tethys Sea of central Australia, before colonizing southern Australia during the upper Eocene after a seaway broke through south of Tasmania. During the Oligocene, the family spread to the north and south, occupying a much more extensive range than their current Indo-Pacific distribution. Fossils suggest the sillaginids ranged as far north as Poland and Germany, and as far south as New Zealand, found in shallow water sedimentary deposits along with other species of extant genera.
At least eight fossil sillaginid species have been found, all of which are believed to be of the genus Sillago based on the only remains found, otoliths. Only one species of extant sillaginid, Sillago maculata, has been found in the fossil record, and this was in very recent Pleistocene sediments. Sillago campbellensis (Schwarzhans, 1985) Australia, Miocene Sillago hassovicus (Koken, 1891) Poland, Middle Miocene Sillago maculata (Quoy and Gaimard, 1824) New Zealand, Middle Pleistocene Sillago mckayi (Schwarzhans, 1985) Australia, Oligocene Sillago pliocaenica (Stinton, 1952) Australia, Pliocene Sillago recta (Schwarzhans, 1980) New Zealand, Upper Miocene Sillago schwarzhansi (Steurbaut, 1984) France, Lower Miocene Sillago ventriosus (Steurbaut, 1984) France, Upper Oligocene
Timeline of genera
Phylogeny
The relationships of the Sillaginidae are poorly known, with very similar morphological characteristics and a lack of genetic studies restricting the ability to perform cladistic analyses on the family. Being the fossil sillaginids are based on the comparison of fossil otoliths, with no other type of remains found thus far, this also prevents the reconstruction of the evolution of the family through fossil species. While the position of the Sillaginidae in the order Perciformes was thought to be firmly established due to a number of synapomorphies shared with other members of that order, no sister group has been established for the family. The 5th edition of Fishes of the World placed Sillaginidae in the order Spariformes but other workers have classified the family as incertae sedis within the series Eupercaria. The current taxonomic status of the family is thought to represent a basic picture of the group's phylogeny, with McKay further dividing the genus Sillago into three subgenera based on shared morphological characters of the swimbladder. The genera Sillaginodes and Sillaginopsis have the most plesiomorphic characteristics; being monotypic, and distinct from Sillago. Sillago is further divided into three subgenera based primarily on swim bladder morphology; Sillago, Parasillago and Sillaginopodys, which also represent evolutionary relationships. Whilst genetic studies have not been done on the family, they have been used to establish the relationship of what were thought to be various subspecies of school whiting, S. bassensis and S. flindersi.Dixon, P.I., Crozier, R.H., Black, M. & Church, A. (1987): Stock identification and discrimination of commercially important whitings in Australian waters using genetic criteria (FIRTA 83/16). Centre for Marine Science, University of New South Wales. 69 p. Appendices 1-10. Furthermore, morphological data suggests a number of Australian species diverged very recently during the last glacial maximum, which caused land bridges to isolate populations of fish. The two aforementioned species of school whiting, S. maculata and S. burrus, and S. ciliata and S. analis are all thought to be products of such a process, although only the school whiting have anything other than similar morphology as evidence of this process.
Morphology