Pacific blue-eye | |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Atheriniformes |
Family: | Pseudomugilidae |
Genus: | Pseudomugil |
Species: | P. signifer |
Binomial name | |
Pseudomugil signifer Kner, 1865 |
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subspecies signifer (dark blue) subspecies signata (light blue) |
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Synonyms | |
Atherina signata Günther, 1867 |
subspecies signata (light blue)
Atherina signata Günther, 1867
Pseudomugil signata (Günther, 1867)
Atherinosoma jamesonii Macleay, 1884
The Pacific blue-eye (Pseudomugil signifer) is a species of fish in the family Pseudomugilidae native to eastern Australia. Described by Austrian naturalist Rudolf Kner in 1866, it comprises two subspecies that have been regarded as separate species in the past and may be once again with further study. It is a common fish of rivers and estuaries along the eastern seaboard from Cape York in north Queensland to southern New South Wales, with the Burdekin Gap in central-north Queensland dividing the ranges of the two subspecies.
A small silvery fish averaging around 3–3.5 cm (1 1⁄8–1 3⁄8 in) in total length, the Pacific blue-eye is recognisable by its blue eye ring and two dorsal fins. It forms loose schools of tens to thousands of individuals. It eats water-borne insects, as well as flying insects that land on the water surface, foraging for them by sight. The Pacific blue-eye adapts readily to captivity.
Austrian naturalist Rudolf Kner described the species in 1866, from a specimen collected in Sydney and taken to Vienna by the SMS Novara in 1858. German-British zoologist Albert Günther described Atherina signata from collections in Cape York in 1867. British entomologist William Sharp Macleay named a "curious little fish", collected from the Bremer River, a tributary of the Brisbane River, by one Mr Jameson of Ipswich, Atherinosoma jamesonii in 1884, which was later classified as the same species by Australian ichthyologist James Douglas Ogilby in 1908. Variable across its range, the Pacific blue-eye is considered to be a single species, though has been split by some into northern signata and southern signifer, with the former found from Ross River northwards and the southern from the Calliope River south. The division occurs at a biogeographic dividing point known as the Burdekin Gap. Gilbert Whitley examined material from the Low Isles off Cairns and split the taxon into P. signifer and P. signata in 1935. In 1979, Hadfield and colleagues analysed the variations described and felt both species were more highly variable than different to each other, and that no characteristics enabled people to distinguish either species. Hence they recommended combining the species again. However, a 2004 molecular study showed the two populations were genetically distinct and suggested that they may be once again reclassified as species. Species from the northern and southern extremes of the range do not appear to interbreed in captivity, suggesting that there may be two separate species within the current concept of the species.