28: MYLIOBATIDAE (EAGLERA YS)
28.4 Rhinoptera javanica: 65 em wide (off Maputo). T = pavement of teeth.
Disc plain brown above, white below, no conspicuous
markings. Attains 150 cm disc width and 45 kg. Indo-West
Pacific, uncommon off Durban and ranging north probably
to India, Thailand, Indonesia and southern China. Eats
bivalves; sometimes congregates in huge shoals.
Family No. 29: MOBULIDAE
by L.J.V. Compagno
Mantas
Mantas
Head, body and pectoral fins form a strongly angular
disc, nearly twice as wide as long. Head in front of spiracles
strongly marked off from rest of disc, with a pair of
elongated, paddle-like cephalic fins, separated by the concave or straight anterior edge of head. Five pairs of gill
openings on underside of disc; internal gill openings
guarded by unique filter plates that allow these rays to filter
small organisms from the water. Jaws with small cuspidate
teeth, normally over 100 rows in each jaw orin 1 jaw only. A
moderate-sized dorsal fin on tail base; a small, vestigial
sting present or absent. Tail slender, whiplike; no caudal fin
or finfolds.
Moderate-sized to gigantic batoid fishes, maximum width
at least 6.7 m. Powerful swimmers, flapping bird-like
through the water and often leaping high into the air. The
horn-like cephalic fins are used to guide small planktonic
and fish prey into the mouth. Harmless except when harpooned from a small boat, as a 1 000 kg specimen leaping
onto a small boat can do considerable damage. Worldwide
134
in tropical and subtropical waters, close inshore and well
out to sea. Two to 4 genera, of which 2 reach the area.
KEY TO GENERA
la Mouth terminal; teeth in lower jaw only; head
broad, width at spiracles greater than length from middle
of upper jaw to 5th gill openings ..................................... Manta
Ib Mouth on underside of head; teeth normally in both
jaws; head width at spiracles less than length from middle
of snout to 5th gill openings ......................................... Mobula
Genus Manta Bancroft, 1829
Possibly a single species, but this is uncertain.
Manta
29.1 Manta birostris
(Donndorff, 1798)
PLATES
Manta
Raja birostris Donndorff, 1798: 876 (no locality). Manta ehrenbergi:
Barnard, 1925: 87. Manta birostris: Smith, SFSA No. 88*; Smith & Smith,
1966: 33*; Wallace, 1967: 13*.
Lower jaw with 130-200 tooth rows. Disc above and below largely
covered with small denticles.
Colour reddish or greenish brown to black above, often
with white patches on shoulders; underside white, edged
with grey. One of the largest of fishes, attains at least 6.7 m
disc width and over 2 tons in weight. Possibly circumtropical, from the Cape eastwards. Harmless plankton
feeders, "flying" slowly through the water but capable of
high speed. Often cartwheeling at the surface or leaping en-
28.4 Rhinoptera javanica: 65 em wide (off Maputo). T = pavement of teeth.
Disc plain brown above, white below, no conspicuous
markings. Attains 150 cm disc width and 45 kg. Indo-West
Pacific, uncommon off Durban and ranging north probably
to India, Thailand, Indonesia and southern China. Eats
bivalves; sometimes congregates in huge shoals.
Family No. 29: MOBULIDAE
by L.J.V. Compagno
Mantas
Mantas
Head, body and pectoral fins form a strongly angular
disc, nearly twice as wide as long. Head in front of spiracles
strongly marked off from rest of disc, with a pair of
elongated, paddle-like cephalic fins, separated by the concave or straight anterior edge of head. Five pairs of gill
openings on underside of disc; internal gill openings
guarded by unique filter plates that allow these rays to filter
small organisms from the water. Jaws with small cuspidate
teeth, normally over 100 rows in each jaw orin 1 jaw only. A
moderate-sized dorsal fin on tail base; a small, vestigial
sting present or absent. Tail slender, whiplike; no caudal fin
or finfolds.
Moderate-sized to gigantic batoid fishes, maximum width
at least 6.7 m. Powerful swimmers, flapping bird-like
through the water and often leaping high into the air. The
horn-like cephalic fins are used to guide small planktonic
and fish prey into the mouth. Harmless except when harpooned from a small boat, as a 1 000 kg specimen leaping
onto a small boat can do considerable damage. Worldwide
134
in tropical and subtropical waters, close inshore and well
out to sea. Two to 4 genera, of which 2 reach the area.
KEY TO GENERA
la Mouth terminal; teeth in lower jaw only; head
broad, width at spiracles greater than length from middle
of upper jaw to 5th gill openings ..................................... Manta
Ib Mouth on underside of head; teeth normally in both
jaws; head width at spiracles less than length from middle
of snout to 5th gill openings ......................................... Mobula
Genus Manta Bancroft, 1829
Possibly a single species, but this is uncertain.
Manta
29.1 Manta birostris
(Donndorff, 1798)
PLATES
Manta
Raja birostris Donndorff, 1798: 876 (no locality). Manta ehrenbergi:
Barnard, 1925: 87. Manta birostris: Smith, SFSA No. 88*; Smith & Smith,
1966: 33*; Wallace, 1967: 13*.
Lower jaw with 130-200 tooth rows. Disc above and below largely
covered with small denticles.
Colour reddish or greenish brown to black above, often
with white patches on shoulders; underside white, edged
with grey. One of the largest of fishes, attains at least 6.7 m
disc width and over 2 tons in weight. Possibly circumtropical, from the Cape eastwards. Harmless plankton
feeders, "flying" slowly through the water but capable of
high speed. Often cartwheeling at the surface or leaping en-