| Family: |
Dalatiidae (Sleeper sharks) |
| Max. size: |
22 cm TL (male/unsexed); 25 cm TL (female) |
| Environment: |
bathypelagic; marine; depth range 200 - 1200 m, oceanodromous |
| Distribution: |
Nearly circumtropical. Western Atlantic: off Bermuda, southern Brazil, and northern Argentina. Eastern Atlantic: off France and Madeira. Western Indian Ocean: off Somalia. Western Pacific: Japan, Taiwan and Philippines (Ref. 13748), as well as Australia (Ref. 7300). |
| Diagnosis: |
Dorsal spines (total): 1-1; Dorsal soft rays (total): 0-0; Anal spines: 0-0; Anal soft rays: 0-0. The spined pygmy shark Squaliolus laticaudus is a very small dogfish (about 25cm) with a large eye (diameter 73-86% of interorbital width), upper margin nearly straight; upper lip without papillae (Ref. 31367, 6871). Color: dark with conspicuously light-margined fins (Ref. 247) . Edge of fins with bright border (Ref. 43998).
S. laticaudus is the type species of the genus which has the following distinctive features: fin spine on its first dorsal fin but not on its second dorsal fin; second dorsal fin long-based and low, about twice the length of first dorsal fin base; first dorsal-fin base closer to pectoral fins than to pelvic fins; and caudal fin nearly symmetrical, paddle-shaped, with subterminal notch present; low lateral keels on caudal peduncle . Body cigar-shaped; snout very long, bulbously conical but slightly pointed; mouth ventral; lips thin; teeth strongly different in both jaws, uppers small, narrow and erect cusps, lowers larger, blade-like and semi erect. Tooth rows 22-23/16-21. (Ref. 247, 6871). |
| Biology: |
An oceanic, wide-ranging, tropical pelagic species occurring near continental and insular land masses, sometimes over the shelves, but usually over the slopes (Ref. 247). Displays vertical migrations on a diel cycle, seen at the bottom during the day and travels to 200 m at night (Ref. 247). Feeds on deepwater squid, lanternfish, gonostomatids and idiacanthids, and probably follows its prey on their diel migrations (Ref. 247). Ovoviviparous (Ref. 205). Has well-developed photophores densely covering the ventral part of the body and sparsely seen on the sides and hardly developed on the dorsal surface (Ref. 247). |
| IUCN Red List Status: |
Least Concern (LC); Date assessed: 21 November 2019 Ref. (130435)
|
| Threat to humans: |
harmless |
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