Stingrays & Skates
http://www.bbc.co.uk/nature/life/Stingray
Pfauenaugen-Stechrochen_-_Ocellate_river_s wikipedia stingray
Characteristics of Rays (and sharks)
 Belong to Class Chondrichthyes
 Sharks and rays don’t look similar on the outside, but
share a basic anatomy that classifies them together.
 Sharks and rays are jawed fish
 lack a swim bladder
 have cartilaginous skeletons - they lack true bone
Special Attributes of Rays (and sharks)
 Sharks and rays have other interesting characteristics:
 Both have lateral lines – lines of sensory hair along the
length of the body that detect water motion and
vibrations
 Unique to elasmobranchs is electroreception – the
ability to sense minute electricity created by muscles
and nerves
 Sharks and rays have organs called ampullae of
Lorenzini which you can see as visible pits near their
snouts used to detect the electrical current
 Have a “conveyor belt” of multiple rows of teeth
Special Attributes of Rays
 Superorder Batidoidimorpha
 Subclass Elasmobranchii consists of the rays, which
includes skates, mantas and guitarfish
Manta Ray
Stingrays
Special Attributes of Rays
 Have an anatomy well suited to life on sandy bottoms
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where they hide in mud or sand
Some are specially adapted to life in midwater such as
eagle ray and manta ray
Have pectoral fin “wings” that stretch forward over the
gills and are fused to the sides of the head
Literally fly through the water
No longer need a tail for swimming, the tail has become
a defensive whip in some species
Stingrays
 family of cartilaginous fish
 containing nine genera and about 70 species
 found in all tropical and sub-tropical seas
 freshwater-only sub-family - the river rays
 flattened body shape and disc-shaped pectoral fins
help stingrays live and hide in sand and mud
 barbed stinger on the tail is only used in self-defense,
often when they are stepped on in shallow waters
Ray Anatomy
Southern Stingray
en.wikipedia.org/wiki/File-Stingray
Absolutedivers.com
Southern Stingray
 Opportunistic forager, feeding on small crustaceans
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such as shrimp and crabs, mollusks, bony fish and
lancelets
Feeds by opening wing-like pectoral fins and expelling
water to disturb sand and expose prey
Often found singly or in pairs
Population density may equal 245 per sq. km in
shallow breeding/ nursery grounds
Bottom-dwelling
 Lie partially buried in sediment
Southern Stingray
 flattened, diamond-shaped body has sharp corners,
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making it more angular than the discs of other rays
top - dorsal side of the body varies between olive
brown and green in adults, dark grey in juveniles,
while ventral underside is white
Slender tail has long serrated spine at the base
Covered in venomous mucous
Used for self-defense
Not fatal to humans but incredibly painful if stepped
on
The
Southern
Stingray
Zooborns.typepad.com
 Eyes are on top of head near spiracles
 Water enters Spiracles while ray is lying on the seabed
 Water bypasses mouth and exits through gill flaps
 Females (150 cm) grow larger than males (67cm) in
width
Southern Stingray- Scientific name:
 Kingdom: Animalia
 Phylum:
Chordata
 Class:
Chondrichthyes
 Subclass: Elasmobranchii
 Order:
Myliobatiformes
 Family:
Dasyatidae (whiptail stingrays)
 Genus:
Dasyatis
 Species: D. americana
Stingray city
Newswise.com
discountexcursions.com
Short-tailed Stingray
Dasyatis_brevicaudata_(Short-tail_stingray)
Blue-spotted Stingray
 ribbon-tail is rounder with brighter blue and more vivid spots
 blue-spotted stingray is larger
 age estimate from one to 18 years of age.
 preyed on by the killer whale & hammerhead shark
targeted by many parasites such as tapeworms, flatworms, and flukes
 found in SE Asia
Favorite catch of fishermen
Blue-spotted Stingray
 Is ovoviviparous – embryos are in eggs within mother’s
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body until they hatch
Embryos receive nourishment from uterine fluid
Give birth up to 7 pups per litter
Range from 6 to 13 (15 to 33 cm) inches at birth
preys on many fish and small mollusks, crabs, and worms
overpowers its prey by pinning them to the bottom of the
seafloor with its fins
does not have teeth, instead it has food-crushing plates on
the sides of its mouth