Superorder BATOIDEA
Rays or Batoids
Cartilaginous fishes with 5 or 6 gill openings below the
pectoral fins, upper edge of orbit fused to eye, dorsal fin(s)
present or absent (without spines in living species), anal fin
absent.
There are between 450 and 500 species of batoids, from
dwarf electric rays (Narke) 10 cm long to sawfishes (Pristis)
at least 7.3 m (possibly 9.8 m) long and mantas 6 or 7 m
wide. Rays inhabit almost all parts of the sea, from the
shore down to over 2 000 m, and from the Arctic to the
Antarctic. A few species of sawfishes (Pristis) and several
marine stingrays (Dasyatidae) readily enter tropical and
warm/temperate rivers. Almost 30 species of stingrays are
confined to freshwater in the tropics, mostly in South
America but with several species in west Africa, southeast
Asia, China and the Australian region.
KEY TO FAMILIES OF BATOID FISHES
1a P not greatly enlarged, body elongated and shark-like ............... 2
1b P greatly enlarged to form a disc, body not shark-like................ 3
2a Snout elongated into a narrow, flat blade
with large teeth on each side ..................... PRISTIDAE (No. 22)
C:~2=:: :::::::::::~
2b Snout not formed into a toothed blade. RHINOBATIDAE (No. 27)
27
3a Large electric organ present on each side of head;
tail stout, C large .............................................................. 4
3b No electric organ on each side of head; tail slender to
thin and whiplike, with or without a small C ............................ 5
4a Mouth very small and transverse; anterior nasal
flaps united or nasal curtain narrow and long;
spiracles immediately behind eyes ............. NARKIDAE (No. 24)
108
Roe of Batoids
4b Mouth large and broadly arched; nasal
curtain broad and short; spiracles a short
distance behind eyes ....................... TORPEDINIDAE (No. 23)
23
Sa Rear margin of V deeply notched, divided into anterior
and posterior lobes; anterior nasal flaps not medially
fused to form a nasal curtain; no sting on tail ........................... 6
5b Rear margin of V not notched or divided; anterior
nasal flaps medially fused to form a nasal curtain;
usually a sting on tail .......................................... ........... ..... 7
6a Two D on tail; a medial row or rows of enlarged
denticles or thorns on tail, and usually thorns and
smaller denticles on disc; tail moderately slender. RAJIDAE (No. 25)
.. '
25
6b No D on tail; no thorns on tail, and no
thorns or denticles on disc except for alar
spines of adult males; tail thin and
whip-like ........................... ANACANTHOBATIDAE (No. 26)
. )
26
7a Six pairs of gill openings on underside of
disc; snout greatly elongated, its length about
half disc width ........................ HEXATRYGONIDAE (No. 31)
31
Rays or Batoids
Cartilaginous fishes with 5 or 6 gill openings below the
pectoral fins, upper edge of orbit fused to eye, dorsal fin(s)
present or absent (without spines in living species), anal fin
absent.
There are between 450 and 500 species of batoids, from
dwarf electric rays (Narke) 10 cm long to sawfishes (Pristis)
at least 7.3 m (possibly 9.8 m) long and mantas 6 or 7 m
wide. Rays inhabit almost all parts of the sea, from the
shore down to over 2 000 m, and from the Arctic to the
Antarctic. A few species of sawfishes (Pristis) and several
marine stingrays (Dasyatidae) readily enter tropical and
warm/temperate rivers. Almost 30 species of stingrays are
confined to freshwater in the tropics, mostly in South
America but with several species in west Africa, southeast
Asia, China and the Australian region.
KEY TO FAMILIES OF BATOID FISHES
1a P not greatly enlarged, body elongated and shark-like ............... 2
1b P greatly enlarged to form a disc, body not shark-like................ 3
2a Snout elongated into a narrow, flat blade
with large teeth on each side ..................... PRISTIDAE (No. 22)
C:~2=:: :::::::::::~
2b Snout not formed into a toothed blade. RHINOBATIDAE (No. 27)
27
3a Large electric organ present on each side of head;
tail stout, C large .............................................................. 4
3b No electric organ on each side of head; tail slender to
thin and whiplike, with or without a small C ............................ 5
4a Mouth very small and transverse; anterior nasal
flaps united or nasal curtain narrow and long;
spiracles immediately behind eyes ............. NARKIDAE (No. 24)
108
Roe of Batoids
4b Mouth large and broadly arched; nasal
curtain broad and short; spiracles a short
distance behind eyes ....................... TORPEDINIDAE (No. 23)
23
Sa Rear margin of V deeply notched, divided into anterior
and posterior lobes; anterior nasal flaps not medially
fused to form a nasal curtain; no sting on tail ........................... 6
5b Rear margin of V not notched or divided; anterior
nasal flaps medially fused to form a nasal curtain;
usually a sting on tail .......................................... ........... ..... 7
6a Two D on tail; a medial row or rows of enlarged
denticles or thorns on tail, and usually thorns and
smaller denticles on disc; tail moderately slender. RAJIDAE (No. 25)
.. '
25
6b No D on tail; no thorns on tail, and no
thorns or denticles on disc except for alar
spines of adult males; tail thin and
whip-like ........................... ANACANTHOBATIDAE (No. 26)
. )
26
7a Six pairs of gill openings on underside of
disc; snout greatly elongated, its length about
half disc width ........................ HEXATRYGONIDAE (No. 31)
31