Sillaginidae

The Sillaginidae, commonly known as the smelt-whitings, whitings, sillaginids, sand borers and sand-smelts, are a family of benthic coastal marine fish in the order Perciformes. 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. 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'. 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. 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.