Common Stingray

The common stingray has been reported to reach a width of 1.4 m (4.6 ft) and a length of 2.5 m (8.2 ft), though a width of 45 cm (18 in) is more typical. The flattened pectoral fin disc is diamond-shaped and slightly wider than it is long, with narrowly rounded outer corners. The leading margins of the disc are almost straight and converge on a pointed, slightly protruding snout; the trailing margins of the disc are convex. The eyes are smaller than the spiracles (paired respiratory openings), which are placed closely behind. There are 28–38 upper tooth rows and 28–43 lower tooth rows; the teeth are small and blunt, and arranged into flattened surfaces. There are five papillae (nipple-like structures) across the floor of the mouth. The tail is slender and whip-like, measuring approximately half as long as the disc. A stinging spine with strong serrations, measuring up to 35 cm (14 in) long and equipped with a venom gland at its base, is positioned about a third of the distance along the tail. A second or even third spine may also be present, as the spines are regularly replaced and new spines grow in before existing ones have been shed. The tail behind the spine bears a low cutaneous fold on top and a short, deep fold underneath. …

The common stingray is found throughout the Mediterranean and Black Seas. It also occurs, though in significantly lower numbers, in the northeastern Atlantic Ocean from southern Norway and the western Baltic Sea to Madeira and the Canary Islands. This bottom-dwelling species can be found from the shore to a depth of 200 m (660 ft), though it is not usually found deeper than 60 m (200 ft). It favors sandy or muddy bottoms in calm water, and is also sometimes encountered near rocky reefs or in estuaries, as it is tolerant of low salinity. Off the Azores, common stingrays are most abundant in summer and least abundant in winter, suggestive of a seasonal shift in range and/or depth as has been documented in other ray species.

Encountered singly or in "social" groups, the common stingray appears to segregate by sex to some degree and may be more active at night, tending to bury itself in sediment during daytime. It feeds on a wide variety of bottom-dwelling organisms, including crustaceans, cephalopods, bivalves, polychaete worms, and small bony fishes. It reportedly does great damage to cultured shellfish beds. One study in the Gulf of İskenderun off Turkey found that crustaceans comprised some 99% of its diet, with fish prey becoming increasingly important with age. Another study off the coast of Tarsus, Turkey, found the most important dietary component to be the penaeid shrimp Metapenaeus stebbingi, followed by the pistol shrimp Alpheus glaber and the swimming crab Charybdis longicollis; cephalopods were relatively important for males, while fishes were important for females. Common stingrays have been observed closely following each other in the presence of food, possibly to take advantage of other individuals' foraging success.

Like other stingrays, the common stingray is aplacental viviparous: the embryos are initially sustained by yolk, which is later supplemented by histotroph ("uterine milk", enriched with proteins, fat, and mucus) delivered by the mother through numerous extensions of the uterine epithelium called trophonemata. …