Smalleye pygmy shark

Taxobox
name = Smalleye pygmy shark
status = LC | status_system = IUCN3.1
trend =


regnum = Animalia
phylum = Chordata
classis = Chondrichthyes
subclassis = Elasmobranchii
ordo = Squaliformes
familia = Dalatiidae
genus = "Squaliolus"
species = "S. aliae"
range_

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range_map_width = 200px
range_map_caption = Range of smalleye pygmy shark (in blue)
binomial = "Squaliolus aliae"
binomial_authority = Teng, 1959The smalleye pygmy shark, "Squaliolus aliae", is a sleeper shark of the family Dalatiidae found in the western Pacific Ocean from Japan to northern Australia, at depths down to 2,000 m. Its length is up to 22 cm.

The smalleye pygmy shark is a very small dogfish characterized by its small eyes, with diameters about 46 to 70% of the interorbital width. The upper lip has a pair of prominent lateral papillae (rarely indistinct). This species is the only shark with a fin spine on its first dorsal fin (spine sometimes concealed by skin) but not on its second dorsal fin - the second dorsal fin is long-based and low, about twice the length of the first dorsal fin base. The first dorsal-fin base is closer to the pectoral fins than to the pelvic fins, and the caudal fin is nearly symmetrical, with a subterminal notch present.

It is possibly the smallest living shark. It feeds mainly on cephalopods and small midwater bony fishes. It probably makes diurnal vertical migrations from within 200 m of the surface at night down to about 2,000 m during the day.

Reproduction is aplacental viviparous (ovoviviparous). Males reach sexual maturity at about 15 cm, females at about 17 cm to 20 cm.

Coloration is dark brown to black, with pale fin margins.

References

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