The smalltooth sand tiger or bumpytail ragged-tooth (Odontaspis ferox) is a species of mackerel shark in the family Odontaspididae, with a patchy but worldwide distribution in tropical and warm temperate waters. They usually inhabit deepwater rocky habitats, though they are occasionally encountered in shallow water, and have been known to return to the same location year after year. This rare species is often mistaken for the much more common sand tiger shark (Carcharias taurus), from which it can be distinguished by its first dorsal fin, which is larger than the second and placed further forward. It grows to at least 5.2 m (17 ft) in length. They have also been recently sighted in Irish and English waters. Very little is known of the biology and behavior of the smalltooth sand tiger. It is an active predator of invertebrates, cartilaginous fishes, and bony fishes from the benthic zone. This species is thought to be ovoviviparous with oophagous embryos like other mackerel sharks. In contrast to its formidable size and appearance, this shark is harmless, having never been known to behave aggressively towards humans. Concern exists that its numbers are declining due to human activities in the Mediterranean and elsewhere, though existing data are inadequate for a full assessment of its conservation status.
Taxonomy and phylogeny The smalltooth sand tiger was originally described as Squalus ferox by Italian-French naturalist Antoine Risso in 1810, based on a specimen from Nice, France. In 1950, Gilbert Percy Whitley described O. herbsti from Australian specimens, separating them from O. ferox on the basis of dentition and the absence of spots. Leonard Compagno synonymized the two species in 1984, as subsequently discovered Pacific specimens had blurred Whitley's distinguishing characters. The specific epithet ferox is Latin for "fierce". Other common names for this shark include blue nurse shark, fierce shark, Herbst's nurse shark, and sand tiger shark. A phylogenetic study based on mitochondrial DNA, performed by Naylor et al. in 1997, suggests that the smalltooth sand tiger and its relative, the bigeye sand tiger (O. noronhai), are more closely related to the thresher sharks than to the grey nurse shark, to which it bears a strong resemblance. If true, this would indicate that the similarities between this species and the grey nurse shark arose as the result of convergent evolution. Fossil teeth belonging to the smalltooth sand tiger have been found from Lower Pliocene from 5.3 to 3.6 million years ago (Mya) in deposits in Italy and Venezuela.
Description The smalltooth sand tiger has a bulky body with a long, bulbous, slightly flattened snout. The eyes are medium-sized, with large, round pupils (as opposed to slit-like in the grey nurse shark), and lack nictitating membranes. The mouth is large and filled with projecting teeth. Each tooth has a narrow, tall central cusp flanked by two or three pairs of lateral cusplets. Some 48–56 tooth rows are in the upper jaw and 36–46 tooth rows are in the lower jaw; the front large teeth in the upper jaw are separated from the lateral teeth by two to five intermediate teeth. The fins are broad-based and angular in shape. The first dorsal fin is larger than the second and placed closer to the pectoral fins than the pelvic fins. The caudal fin is strongly asymmetrical with the upper lobe much longer than the lower. The coloration is gray to gray-brown above and lighter below. Juveniles are uniform in color with darker fin margins, while adults often exhibit dark spots or blotches that vary widely in pattern, size, and density. Coloration also appears to vary by region, with some individuals from the Mediterranean displaying a patchy, "piebald" pattern. The smalltooth sand tiger attains a maximum length of 5.2 m (17 ft) per Kukuev & Batal'yants, 2019 and a maximum weight of 289 kg (637 lb). There are unconfirmed reports of much larger individuals from Malpelo Island off Colombia.
Distribution and habitat
Smalltooth sand tigers have been caught at widely scattered locations throughout the world, indicating a possibly circumtropical distribution. In the eastern Atlantic Ocean, it is known from the Bay of Biscay south to Morocco, including the Mediterranean Sea, the Azores, and the Canary Islands. In March 2023, the species was also found in The Solent after a dead smalltooth sand tiger washed ashore at Lepe, Hampshire, and the following month a 14-foot (4.3 m) specimen was found in County Wexford, Ireland. In the western Atlantic, it has been reported from off North Carolina and Florida (USA), the Yucatan Peninsula (Mexico), Fernando de Noronha (Brazil) and even, much more recently, from Malpelo Island near Colombia. It occurs throughout the Indian Ocean, from South Africa, Madagascar, and Tanzania in the west to the Maldives and the Southwest Indian Ridge in the east. In the northern Pacific, it is known from off Japan, Hawaii, California, and in the southern Pacific it is known from New Caledonia, eastern Australia, and New Zealand. In New Zealand, this species can be found off the coasts of the Bay of Plenty, New Plymouth, and Hawkes Bay. It has also been filmed near Raoul Island. Typically regarded as a deepwater species, smalltooth sand tigers have been caught down to 880 m (2,890 ft). They are usually found near the bottom in rocky, boulder-strewn regions on continental shelves and the upper continental slope, as well as around submarine ridges and mountains. The species has been reported near the drop-offs of rocky or coral reefs and in the upper layers of the open ocean. In the Mediterranean, smalltooth sand tigers occur at depths less than 250 m (820 ft), including at depths accessible to divers. They have been seen swimming over sandy flats at Cocos Island and Fernando de Noronha. The temperature range favored by this species is 6–20 °C (43–68 °F); in hot climates, they are found below the thermocline in cooler water.
Biology and ecology
… excerpt ends here. Continue reading the full article.
