Biology:Stargazer (fish)

Short description: Family of fishes

Stargazer
Common stargazer, Kathetostoma laeve
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Trachiniformes
Family:	Uranoscopidae Jordan & Evermann, 1898
Genera
See text

The stargazers are a family, Uranoscopidae, of perciform fish that have eyes on top of their heads (hence the name). The family includes about 51 species (one extinct) in eight genera, all marine and found worldwide in shallow and deep saltwaters.

Description

In addition to the top-mounted eyes, a stargazer also has a large, upward-facing mouth in a large head. Their usual habit is to bury themselves in sand, and leap upwards to ambush prey (benthic fish and invertebrates) that pass overhead. Some species have a worm-shaped lure growing out of the floors of their mouths, which they can wiggle to attract prey's attention. Both the dorsal and anal fins are relatively long; some lack dorsal spines. Lengths range from 18 up to 90 cm, for the giant stargazer Kathetostoma giganteum.

Stargazers are venomous; they have two large venomous spines situated behind their opercles and above their pectoral fins. The species within the genera Astroscopus and Uranoscopus can also cause electric shocks. Astroscopus species have a single electric organ consisting of modified eye muscles, while Uranoscopus species have theirs derived from sonic muscles. These two genera within stargazers represent one of eight independent evolutions of bioelectrogenesis. They are unique among electric fish in not possessing electroreceptors, meaning that they do not use an electric sense to locate prey.

Stargazer's paired electric organs are aligned vertically inside the head, behind the eyes. Uniquely, they are used only for hunting or defence, as the fish does not electrolocate.

Stargazers are a delicacy in some cultures (the venom is not poisonous when eaten), and they can be found for sale in some fish markets with the electric organ removed. Stargazers are ambush predators which camouflage themselves; some can deliver both venom and electric shocks. Ichthyologist William Leo Smith called them "the meanest things in creation".

Genera

Uranscopidae contains the following genera:

• Xenocephalus Uranoscopus
• Kathetostoma Astroscopus
• Brevoort, 1860 Gill, 1861
• Günther, 1860 Kaup, 1858
• Pleuroscopus Ichthyscopus
• Barnard, 1927 Linnaeus, 1758
• Genyagnus Swainson, 1839
• Okamura & Kishimoto, 1993 Selenoscopus

• 

  Deepwater stargazer
  (Kathetostoma nigrofasciatum)

• 

  Northern stargazer
  (Astroscopus guttatus)

• 

  Whitemargin stargazer
  (Uranoscopus sulphureus)

• 

  Southern stargazer
  (Astroscopus y-graecum)

Timeline

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from: -55.8   till:  -33.9    color:eocene  text:Eocene 
from: -33.9   till:  -23.03    color:oligocene  text:Oligocene            
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Further reading

External video

Stargazer lunges from sand – YouTube

Little Red Cardinalfish gets eaten by hidden Stargazer! – YouTube

• Gomon, M.F.; Roberts, C.D. (2011). "A second New Zealand species of the stargazer genus Kathetostoma (Trachinoidei: Uranoscopidae)". Zootaxa 2776: 1–12. doi:10.11646/zootaxa.2776.1.1. 

Wikidata ☰ Q183280 entry