Order COELACANTHIFORMES
Coelacanths
Notochord unconstricted (no vertebral centra are developed); snout with a pair of external nostrils on each side
and a median rostral organ of unknown function; maxilla
and median gular bone absent; caudal fin diphycercal, with
notochord extending into the exserted midlateral lobe of
the symmetrical tail.
The name "coelacanth" means "hollow spine", and refers
to the "backbone" or spine - a tube of tough thick cartilage
(called a notochord) filled with liquid. In the embryonic
development of most fishes and other vertebrate animals,
the notochord is replaced by bony centra which form the
base for the vertebrae of the spinal column.
Four families, of which 3 have become extinct.
Family No. 35: LATIMERIIDAE
by Margaret M. Smith
Coelacanths
Seelakante
Second dorsal, anal and paired fins fringed lobes; axial
skeleton mainly cartilaginous; no ribs or branchiostegal
rays. A single species.
Coelacanth
35.1 Latimeria chalumnae
Smith,1939
PLATE 9
Seelakant
Latimeria chalumnae Smith, 1939: 455, Fig. (southwest of East London
in about 70 m); 1939: 47*; 1940: 1·106*; SFSA No. 98*; 1953: 279; Millot,
1953: 18*; Millot & Anthony, 1958: 2553-2597*; Smith et al., 1975: 1105*
(embryo); McCosker & Lagios (ed.), 1979: 1-175*; Locket, 1980. Malania
anjouanae Smith, 1953: 99, Fig. (Anjouan Id., Comores); SFSA No. 98a*;
1953: 279.
D VIII+30; A 27-31; P 29-32; V 29-33; C 25+38+21; GR represented
by numerous different sized teeth; LL 76-82 + 15-23 on supplementary
caudal; 2nd D, A, P and Vall fringed lobes; gill opening edge tough skin,
free from isthmus; gills 4, spinescent; tongue bony; intracranial joint
present; teeth conical, of various lengths set in discrete bony plates that
are attached to the bones of the jaws by dense fibrous ligaments; premaxilla cartilaginous, lower jaw with 2 overlapping gular plates not connected along midline. Opercular bones heavy, mostly external to skin,
subopercle and interopercle large adapted scales; remaining skull bones
light, covered by skin. Body robust, subquadrangular, covered with
heavily armoured bony overlapping scales with only one third exposed.
Internal anatomy very primitive, especially the heart; swimbladder
elongate, filled with fat; liver fatty; intestine with spiral valve; osmoregulation by retention of urea and trimethylamine oxide in the blood and
secretions of the rectal gland; notochord, a large, thick-walled cartilaginous tube filled with liquid, supports the spinal cord. In the adult, the brain
152
Seelakante
is incredibly small, occupying only about 0.01 of the cranial cavity. Male
with 2, female with 4 external openings before A; ovoviviparous, gestation period probably about 13 months.
Colour: whole fish mauvish blue rapidly fading to brown;
with numerous irregularly shaped white marks over body. It
is almost impossible to age coelacanths by scale rings as they
vary so much on a single specimen. The discovery of ovovivipary has shown that coelacanths grow rapidly and are
younger than originally estimated. Now it is suggested they
reach 8-10 years, at which age they are about 200 cm in
length and weigh some 60 kg; females are larger than males.
Apart from the first specimen trawled off East London and
despite intensive search, the remaining 100 or more specimens have been caught by hook and line, only off Grand
Comoro and Anjouan Islands, Comoro group, the favourite bait being Promethichthys prometheus, a gempylid fish
related to our snoek.
Flesh good, especially when marinated; the fact that it is
not esteemed by the Comoro Islanders is probably due to
the tropical temperatures causing oil from the fatty layer
below the skin to percolate through the flesh, giving it a
rancid flavour.
Experts are divided as to whether coelacanths are more
closely related to sharks and rays than to bony fishes. The
latter view is held here and they are placed in the Class
Osteichthyes. A short history of the discovery of this remarkable fish (by many considered to be the closest relative
to Rhipidistia, recognised as the ancestor of all land animals) follows:
On 22 December 1938 the Irvin & Johnson trawler
Nerine, with Captain Goosen in charge, trawled the first
live coelacanth known to scientists. Saved by Miss Courtenay-Latimer, the young curator of the East London
Museum, it was recognised as a coelacanth by Professor
J.L.B. Smith, who described and named it Latimeria
chalumnae in honour of Miss Courtenay-Latimer and the
river near where it was trawled. Unfortunately, the soft
parts of the first specimen were discarded before they could
be studied; consequently to obtain a second, intact specimen was of tremendous importance. By the late 1940s,
there was little doubt that the East London coelacanth was a
stray; and J.L.B. Smith deduced that the home of the
coelacanth was to the north, in the Mozambique Channel.
A pamphlet depicting a coelacanth and offering a reward
resulted in one caught on 21 December 1952 off Anjouan Island, being saved for science by Captain Eric Hunt.
Coelacanths
Notochord unconstricted (no vertebral centra are developed); snout with a pair of external nostrils on each side
and a median rostral organ of unknown function; maxilla
and median gular bone absent; caudal fin diphycercal, with
notochord extending into the exserted midlateral lobe of
the symmetrical tail.
The name "coelacanth" means "hollow spine", and refers
to the "backbone" or spine - a tube of tough thick cartilage
(called a notochord) filled with liquid. In the embryonic
development of most fishes and other vertebrate animals,
the notochord is replaced by bony centra which form the
base for the vertebrae of the spinal column.
Four families, of which 3 have become extinct.
Family No. 35: LATIMERIIDAE
by Margaret M. Smith
Coelacanths
Seelakante
Second dorsal, anal and paired fins fringed lobes; axial
skeleton mainly cartilaginous; no ribs or branchiostegal
rays. A single species.
Coelacanth
35.1 Latimeria chalumnae
Smith,1939
PLATE 9
Seelakant
Latimeria chalumnae Smith, 1939: 455, Fig. (southwest of East London
in about 70 m); 1939: 47*; 1940: 1·106*; SFSA No. 98*; 1953: 279; Millot,
1953: 18*; Millot & Anthony, 1958: 2553-2597*; Smith et al., 1975: 1105*
(embryo); McCosker & Lagios (ed.), 1979: 1-175*; Locket, 1980. Malania
anjouanae Smith, 1953: 99, Fig. (Anjouan Id., Comores); SFSA No. 98a*;
1953: 279.
D VIII+30; A 27-31; P 29-32; V 29-33; C 25+38+21; GR represented
by numerous different sized teeth; LL 76-82 + 15-23 on supplementary
caudal; 2nd D, A, P and Vall fringed lobes; gill opening edge tough skin,
free from isthmus; gills 4, spinescent; tongue bony; intracranial joint
present; teeth conical, of various lengths set in discrete bony plates that
are attached to the bones of the jaws by dense fibrous ligaments; premaxilla cartilaginous, lower jaw with 2 overlapping gular plates not connected along midline. Opercular bones heavy, mostly external to skin,
subopercle and interopercle large adapted scales; remaining skull bones
light, covered by skin. Body robust, subquadrangular, covered with
heavily armoured bony overlapping scales with only one third exposed.
Internal anatomy very primitive, especially the heart; swimbladder
elongate, filled with fat; liver fatty; intestine with spiral valve; osmoregulation by retention of urea and trimethylamine oxide in the blood and
secretions of the rectal gland; notochord, a large, thick-walled cartilaginous tube filled with liquid, supports the spinal cord. In the adult, the brain
152
Seelakante
is incredibly small, occupying only about 0.01 of the cranial cavity. Male
with 2, female with 4 external openings before A; ovoviviparous, gestation period probably about 13 months.
Colour: whole fish mauvish blue rapidly fading to brown;
with numerous irregularly shaped white marks over body. It
is almost impossible to age coelacanths by scale rings as they
vary so much on a single specimen. The discovery of ovovivipary has shown that coelacanths grow rapidly and are
younger than originally estimated. Now it is suggested they
reach 8-10 years, at which age they are about 200 cm in
length and weigh some 60 kg; females are larger than males.
Apart from the first specimen trawled off East London and
despite intensive search, the remaining 100 or more specimens have been caught by hook and line, only off Grand
Comoro and Anjouan Islands, Comoro group, the favourite bait being Promethichthys prometheus, a gempylid fish
related to our snoek.
Flesh good, especially when marinated; the fact that it is
not esteemed by the Comoro Islanders is probably due to
the tropical temperatures causing oil from the fatty layer
below the skin to percolate through the flesh, giving it a
rancid flavour.
Experts are divided as to whether coelacanths are more
closely related to sharks and rays than to bony fishes. The
latter view is held here and they are placed in the Class
Osteichthyes. A short history of the discovery of this remarkable fish (by many considered to be the closest relative
to Rhipidistia, recognised as the ancestor of all land animals) follows:
On 22 December 1938 the Irvin & Johnson trawler
Nerine, with Captain Goosen in charge, trawled the first
live coelacanth known to scientists. Saved by Miss Courtenay-Latimer, the young curator of the East London
Museum, it was recognised as a coelacanth by Professor
J.L.B. Smith, who described and named it Latimeria
chalumnae in honour of Miss Courtenay-Latimer and the
river near where it was trawled. Unfortunately, the soft
parts of the first specimen were discarded before they could
be studied; consequently to obtain a second, intact specimen was of tremendous importance. By the late 1940s,
there was little doubt that the East London coelacanth was a
stray; and J.L.B. Smith deduced that the home of the
coelacanth was to the north, in the Mozambique Channel.
A pamphlet depicting a coelacanth and offering a reward
resulted in one caught on 21 December 1952 off Anjouan Island, being saved for science by Captain Eric Hunt.