{{Short description|Species of fish}} {{Speciesbox | image = Atherinomorus lacunosus (Hardyhead silverside).gif | status = LC | status_system = IUCN3.1 | status_ref = <ref name = iucn>{{cite iucn | author1 = Monroe, T. | author2 = Feary, D. | name-list-style = amp | year = 2015 | title = ''Atherinomorus lacunosus'' | volume = 2015 | article-number = e.T18123573A56972262 | access-date = 19 July 2019 | url = https://www.iucnredlist.org/species/18123573/56972262}}</ref> | taxon = Atherinomorus lacunosus | authority = (J. R. Forster, 1801) | synonyms ={{Specieslist |Atherina lacunosa |Forster, 1801 |Atherinomorus lacunosa|(Forster, 1801) |Pranesus lacunosus|(Forster, 1801) |Atherina affinis|Bennett, 1832 |Atherina punctata|Bennett, 1833 |Atherina morrisi|Jordan & Starks, 1906 |Atherion morrisi|(Jordan & Starks, 1906) |Hepsetia morrisi|(Jordan & Starks, 1906) |Pranesus morrisi|(Jordan & Starks, 1906) |Pranesus capricornensis|Woodland, 1961 |Atherinomorus capricornensis|(Woodland, 1961) |Pranesus maculatus|Taylor, 1964 }} | synonyms_ref = <ref name = Synonyms>{{Cite web | url = http://www.fishbase.org/Nomenclature/SynonymsList.php?ID=1303&SynCode=23385&GenusName=Atherinomorus&SpeciesName=lacunosus| title = Synonyms of Atherinomorus lacunosus (Forster, 1801) | access-date = 17 March 2017 | publisher = Fishbase}}</ref> }} The '''hardyhead silverside''' ('''''Atherinomorus lacunosus'''''), also known as the '''broad-banded hardyhead''', '''broad-banded silverside''', '''Capricorn hardyhead''', '''pitted hardyhead''', '''robust hardyhead''', '''robust silverside''', '''slender hardyhead''' and '''wide-banded hardyhead silverside''', is a silverside of the family Atherinidae. It occurs in the Indo-Pacific near the surface as well as in the Mediterranean, having invaded as a Lessepsian migrant through the Suez Canal. left|thumb|A bank of young ''Atherinomorus lacunosus''.
==Description== The hardyhead silverside is a robust, broad headed, small fish<ref name = "Van der Elst"/> which is distinguished by having a very low and wide lateral process of premaxilla with the upper margin of the anterior bone of the lower jaw which bears the teeth is almost flat distally and has no distinct tubercle at its posterior end. The posterior of the jaw reaches at least as far as the vertical through anterior margin of the pupil. The mouth has small teeth on palate which do not form obvious ridges. The anus is usually behind but close to the posterior tip of the pelvic fin. There are 18–24 lower gill rakers and the midlateral scale count is 40–44. The lower edge of the midlateral band reaches below the ventral end of the third scale row and nearly extends to the center of the fourth scale row where it is level with the origin of the anal fin. The dorsal fin has 5–8 spines and 9–10 soft rays while the anal fin has 1 spine and 12–17 soft rays and it has 43–44 vertebrae.<ref name = Fishbase>{{FishBase |Atherinomorus|lacunosus |id=1303|month= March|year= 2016}}</ref> They can grow up to {{cvt|14|cm}} but are more usually in the range {{cvt|10–12|cm}}.<ref name = MSIP>{{Cite web | url = http://species-identification.org/species.php?species_group=fnam&id=1138 | title = Fishes of the NE Atlantic and the Mediterranean - ''Atherinomorus lacunosus'' | access-date = 17 March 2017 | publisher = ETI Bioinformatics | work = Marine Species Identification Portal | author = J.C. Huraeu}}</ref> Freshly caught specimens are overall silvery in colour, tending to greenish on the dorsal area but with a bright blue strip along the flank, dusky fins and a translucent appearance when seen live in the water.<ref name = "Van der Elst"/>
==Distribution== The hardyhead silverside has an Indo-Pacific distribution which extends from the eastern coasts of Africa east to Tonga, north as far as southern Japan, and south to northern Australia; it appears to be absent in the Andaman Sea and to be replaced by ''Atherinomorus insularum'' in Hawaii.<ref name = Fishbase/> It was the second species of Red Sea creature, following ''Pampus argenteus,''{{Citation needed|date=May 2017}} to be recorded in the Mediterranean Sea following the opening of the Suez Canal in 1869, being reported by Tillier in 1902<ref name = Bucciarelli>{{cite journal | author1 = Giuseppe Bucciarelli | author2 = Daniel Golani | author3 = Giacomo Bernardi | year = 2002 | title = Genetic cryptic species as biological invaders: the case of a Lessepsian fish migrant, the hardyhead silverside ''Atherinomorus lacunosus'' | url = http://bio.research.ucsc.edu/people/bernardi/Bernardi/Publications/2002Lessepsians.pdf | journal = Journal of Experimental Marine Biology and Ecology | volume = 273 | issue = 2 | pages = 143–149 | doi=10.1016/s0022-0981(02)00138-7 | bibcode = 2002JEMBE.273..143B }}</ref> and had spread north westwards as far as Greece.<ref name = Update>{{cite journal | author1 = M.A. Pancucci-Papadopoulou | author2 = A. Zenetos | author3 = M. Corsina-Foka | author4 = C.Y. Politou | year = 2005 | title = Update of Marine Alien Species in Hellenic Waters | url = http://www.medit-mar-sc.net/index.php/marine/article/view/188/188 | journal = Mediterranean Marine Science | volume = 6 | issue = 2 | pages = 147–158 | doi=10.12681/mms.188| doi-access = free | bibcode = 2005MedMS...6..147P }}</ref>
==Biology== The hardyhead silverside occurs commonly in large schools along sandy shorelines and reef margins. It is reported to be a largely nocturnal fish which forms schools numbering from several hundred individuals to aggregations which may be over {{cvt|100|m}} long and {{cvt|20|m}} wide. Feeds on a wide variety of plankton and small benthic invertebrates with foraging taking place mostly during the night following the dispersal of the schools.<ref name = Fishbase/><ref name = eol>{{EOL |46566613|''Atherinomorus lacunosus'' | access-date = 17 March 2017}}</ref> It can also be found in estuarine waters.<ref name = "Van der Elst"/>
In New Caledonia, hardyhead silversides attain sexual maturity just before they reach a year old, spawning from late August through to December. The species has a relatively low fecundity and this combined with the extended spawning season suggests that this species utilises a spawning strategy which involves each individual female spawning a number of times. They have a short lifespan and most normally die after the spawning season although some individuals survived into their second year. However, in the Seychelles there were two spawning seasons, in April–June and in September–December, which corresponded to the periods of warmer water between the monsoons while in the Marshall Islands spawning occurred all year.<ref name = Conand>{{cite journal | author = F. Conand | year = 1993 | title = Life history of the silverside ''Atherinomorus lacunosus'' (Atherinidae) in New Caledonia | url = http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/b_fdi_35-36/42762.pdf | journal = Journal of Fish Biology | volume = 42 | issue = 6 | pages = 851–863 | doi=10.1111/j.1095-8649.1993.tb00395.x | bibcode = 1993JFBio..42..851C }}</ref> In South Africa spawning has been observed near estuaries and takes place from October to January. The eggs bear fine filaments which are used to adhere the eggs to the substrate or to other submerged surfaces.<ref name = "Van der Elst"/>
The hardyhead silverside is an important forage fish for larger fish species<ref name = eol/> such as sharks, tunas, needlefish and amberjacks which capture them by associating with and attacking the day schools. They are also preyed on by sea birds such as terns, boobies, gulls, egrets and herons.<ref name = Fishbase/> It also plays host to parasites such as the cymothoid isopod ''Livoneca''<ref name = Colornil>{{cite journal | author1 = Angelo Colornil | author2 = Jean-Paul Trilles | author3 = Daniel Golani | year = 1997 | title = Livoneca sp. (Flabellifera: Cymothoidae), an isopod parasite in the oral and branchial cavities of the Red Sea silverside Atherinomorus lacunosus (Perciformes, Atherinidae) | url = https://www.int-res.com/articles/dao/31/d031p065.pdf | journal = Diseases of Aquatic Organisms | volume = 31 | pages = 65–71 | doi=10.3354/dao031065| doi-access = free }}</ref> and the trematodes ''Overstreetia cribbi'' and ''O. sodwanaensis''.<ref name = WoRMS_768094>{{cite WoRMS | id=768094 | title = ''Atherinomorus lacunosus'' (Forster, 1801) | access-date = 17 March 2017 | author = N. Bailly | year = 2008}}</ref>
==Uses== The hardyhead silversides is sold fresh, or salted and dried in Asia<ref name = "Van der Elst">{{cite book | author = Rudy Van der Elst | title = A Guide to the Common Sea Fishes of Southern Africa | url = https://archive.org/details/guidetocommonsea00elst | url-access = limited | page = [https://archive.org/details/guidetocommonsea00elst/page/n122 123] | publisher = Struik | year = 1993 | isbn = 978-1-86825-394-4}}</ref> and is referred to a whitebait in some English speaking parts of the world where it occurs.<ref name = Fishbase/>
==Taxonomy and naming== ''Atherinomorus lacunosus'' has been lumped with ''A. forskalli'' and ''A. pinguis'' in the past but is now regarded as separate,<ref name = Kimura>{{cite journal | author1 = Seishi Kimura | author2 = Daniel Golani | author3 = Yukio Iwatsuki |author4 = Motohiko Tabuchi | author5 = Tetsuo Yoshino | year = 2007 | title = Redescriptions of the Indo-Pacific atherinid fishes ''Atherinomorus forskalii'', ''Atherinomorus lacunosus'', and ''Atherinomorus pinguis'' | journal = Ichthyological Research | volume = 54 | issue = 2 | pages = 145–159 | doi=10.1007/s10228-006-0386-7 | bibcode = 2007IchtR..54..145K }}</ref> although this has caused some confusions as to whether the species which has invaded the Mediterranean is ''A. lacunosus'' or ''A. forskalli''.<ref name = Fishbase2>{{FishBase |Atherinomorus|forskalii | month= March | year = 2016}}</ref> More recent DNA studies have shown that this species, and other species in the genus ''Atherinomorus'', are actually made up of a number of cryptic species and that the populations identified as ''A. lacunosus'' in the Red Sea and Mediterranean may represent three such species.<ref name = Bucciarelli/>
The name ''Atherinomorus lacunosus'' means the hollow bearing (''lacunosis'') smelt (''Atherinomorus''), while the common name refers to its robust head and silvery flanks.<ref name = "Van der Elst"/>
==References== {{Reflist}}
{{Taxonbar|from=Q3239341}}
Category:Atherinomorus Category:Taxa named by Johann Reinhold Forster Category:Fish described in 1801