1. Natural History of Sharks, Skates, and Rays
Phylogeny of Batoidea
MARE 394
Dr. Turner
Summer 2009

2. Zoogeographic Patterns
Superorder Batoidea – electric rays, sawfishes, guitarfishes, skates, & stingrays
Range for polar to tropical seas
4 Orders
3 Suborders
4 Superfamilies
13 Families
6 Subfamilies
79 Genera
500 Species

3. Superorder Batoidea Orders: Torpediniformes – electric rays
Pristiformes – sawfishes
Rajiformes – true rays
Mylobatiformes – eagle rays

4. Order Torpediniformes
Family Torpedinidae – (electric rays)
Family Narcinidae – (electric rays)
Torpedo ray
Torpedo nobiliana
Numbfish
Narcine maculata

5. Torpedinidae Family Torpedinidae – (electric rays)
Torpedo ray
Torpedo nobiliana
Bottom dwelling, shallow coastal waters to 1,000 m
Slow moving, propelling themselves along with their tails
Feed on invertebrates and small fish
Prey below the sand using electricity to stun and capture

6. Narcinidae Family Narcinidae – (electric rays)
Slow-swimming bottom-dwellers that feed on small fishes and invertebrates off the bottom
Generate a moderate shock if disturbed and contact is made with the electric organs
Electrical discharges of narcinids have been measured at 8-37 volts, much less than the electric rays of the genus Torpedo
Numbfish
Narcine maculata

7. Order Pristiformes Family Pristidae – (sawfishes)
Common sawfish
Pristis pristis
Although they are similar in appearance, sawsharks are distinct from sawfish. Sawfish have a much larger maximum size, lack barbels, have evenly sized rather than alternating sawteeth, and have gill slits on their undersurface rather than on the side of the head

8. Rhinobatos rhinobatos
Order Rajiformes
Family Rhinobatidae – (guitarfishes)
Family Rajidae – (skates)
Common guitarfish
Rhinobatos rhinobatos
Big Skate
Raja binoculata

9. Rhinobatos rhinobatos
Rhinobatidae
Family Rhinobatidae – (guitarfishes)
Common guitarfish
Rhinobatos rhinobatos
To 225 kg (500 lb) to 3 m (9.8 ft) in length, Ovoviviparous
Bottom feeders, preferring small crustaceans
Teeth are small and numerous, arranged in 65 or 70 rows
Body form intermediate between those of sharks and rays
Tail has a typical ray-like form, head has a triangular shape

10. Rajidae Family Rajidae – (skates)
Benthic rays occurring in all oceans, from Arctic to Antarctic waters and from shallow coastal shelfs to abyssal regions
Tail slender, 2 reduced dorsal fins and a reduced caudal fin
Skin prickly in most species, the prickles often in a row along midline of dorsal
Disc quadrangular to rhomboidal
Five pairs of ventral gill slits
Oviparous
Big Skate
Raja binoculata

11. Pteroplatytrygon violacea
Order Mylobatiformes
Family Platyrhinidae – (thornback ray)
Family Zanobatidae – (pan rays)
Family Hexatrygonidae – (longsnout stingray)
Family Urolophidae – (round rays)
Family Urotrygonidae – (smalleyed round ray)
Family Dasyatidae – (stingrays)
Family Potamotrygonidae – (river rays)
Family Gymnuridae – (butterfly rays)
Family Myliobatidae – (eagle rays)
Spotted eagle ray
Aetobatus narinari
Pelagic stingray
Pteroplatytrygon violacea        

12. Platyrhinidae Family Platyrhinidae – (thornback ray)
To 1 m (3.3 ft) from 4.5 to 8.75 lb (2 to 3.98 kg)
In sexually mature fish some of the spines are thickened with button-like bases (known as bucklers)
Usually found on mud, sand or gravel 10-60m
Feed on small crustaceans, amphipods shrimps, crabs, and small fish.
Thornback ray
Raja clavata

13. Zanobatus schoenleinii
Zanobatidae
Family Zanobatidae – (pan rays)
Occurs in shallow coastal waters to moderate depth, over sandy and sandy-muddy bottoms
Feeds on mollusks and other benthic invertebrates
Ovoviviparous
Striped panray
Zanobatus schoenleinii

14. Hexatrygonidae Family Hexatrygonidae – (sixgill stingray)
Snout translucent, depressed, produced and may act as an electroreceptive organ
Large spiracles with external flaplike valve and well behind eyes
Two serrate spines in tail; Length of disc greater than width
Feeding habits unknown
6 Gill openings
Sixgill stingray
Hexatrygon bickelli

15. Urolophidae Family Urolophidae – (round rays)
Well-developed caudal fin; tail moderately long;
Anterior margin of pectorals continuous along side of head
One or more long poisonous spines on tail
Feed benthic invertebrates, copepods, amphipods, mysids
Oviparous
Round ray
Rajella fyllae

16. Urotrygonidae Family Urotrygonidae – (American round stingrays)
Disc width less than 1.3 times disc length
Tail slender as long as the disc; No dorsal fin
Distinct poisonous spines; Previously in Urolophidae
Smalleyed round stingray
Urotrygon microphthalmum

17. Pteroplatytrygon violacea
Dasyatidae
Family Dasyatidae – (stingrays)
Chiefly marine; also in brackish and freshwater
Side of head continuous with the anterior margin of pectoral fin
Tail long and whip-like. venomous spine on tail, which can cause excruciating pain to humans
Largest species to about 4m
Ovoviviparous
Pelagic stingray
Pteroplatytrygon violacea        

18. Potamotrygonidae Family Potamotrygonidae – (river rays)
Potamotrygonids are much maligned and feared because of their venomous caudal stings, but pose little or no threat if not stepped on or directly interfered with. The Potamotrygonidae is the only living chondrichthyan family restricted to freshwater habitats.
Raspy river stingray
Potamotrygon scobina 

19. Twin-spot butterfly ray
Gymnuridae
Family Gymnuridae – (butterfly rays)
Atlantic, Indic and Pacific Oceans
Marine, rarely in estuaries
Outer anterior margin of pectorals continuous along side of head
Dorsal fin and tail spines present or absent
Disc extremely broad
Tail short
Twin-spot butterfly ray
Gymnura bimaculata

20. Myliobatidae Family Myliobatidae – (eagle rays)
Head elevated above disc
Jaws powerful with large platelike crushing teeth
Pectoral fins reduced or absent opposite the eyes
Some known for their leaping ability high into the air
Viviparous
Spotted eagle ray
Aetobatus narinari