Knowledge Related to Handfish
Handfish are any anglerfish within the family Brachionichthyidae, a group which comprises five genera and 14 extant species. These benthic marine fish are unusual in the way they propel themselves by walking on the sea floor rather than swimming
· Other Related Knowledge of video scaler
Distribution of video scaler
Handfish are found today in the coastal waters of southern and eastern Australia and Tasmania. This is the most species-rich of the few marine fish families endemic to the Australian region.
The biology of handfishes is poorly known and their typically small population sizes and restricted distributions make them highly vulnerable to disturbance. Some species are considered to be critically endangered.
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Anatomy of video scaler
Handfish grow up to 15Â cm (5.
9Â in) long, and have skin covered with denticles (tooth-like scales), giving them the alternate name warty anglers. They are slow-moving fish that prefer to 'walk' rather than swim, using their modified pectoral fins to move about on the sea floor. These highly modified fins have the appearance of hands, hence their scientific name, from Latin bracchium meaning "arm" and Greek ichthys meaning "fish".
Like other anglerfish, they possess an illicium, a modified dorsal fin ray above the mouth, but it is short and does not appear to be used as a fishing lure.dubious discuss The second dorsal spine is joined to the third by a flap of skin, making a crest.
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Extinction of video scaler
In March 2020, the smooth handfish (Sympterichthys unipennis) was declared extinct in the IUCN Red List.
Once common enough to be one of the first fish to be described by European explorers of Australia, but not seen for well over a century, this is the first modern-day marine fish to be officially declared extinct. In 1996, the spotted handfish (Brachionichthys hirsutus) was the first marine fish to be listed as critically endangered in the IUCN Red List.
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Fossil record of video scaler
The prehistoric species, Histionotophorus bassani, from the Lutetian of Monte Bolca, is now considered to be a handfish, sometimes even being included in the genus Brachionichthys.
Considering the low extant diversity, restricted geographical distribution, and very meager fossil record of antennarioids in general, the existence of fossil representatives of the family Brachionichthyidae is unusual.
