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| The
wormfishes are tiny and rarely-seen
relatives of the gobies. There are only
two Caribbean genera: Cerdale
floridana and the genus Microdesmus
with five regional species.
Fortunately, fin-ray counts clearly
distinguish the regional species, which
share almost all other larval characters
and markings. Despite the small size
of the adults, the larvae are large
and not uncommon in larval collections. |
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| Larval
microdesmids are long and worm-like
with a prominent mid-body swim bladder.
They have a characteristically blunt,
hooked, and protruding lower jaw and
more, usually many more, than 35 elements
in the dorsal fin and 23 in the anal
fin. These features easily distinguish
them from the gobies
and other gobioids.
Wormfish larvae are morphologically
similar to the larval pikeblennies of
Chaenopsis,
but the latter have long and thread-like
pelvic fins while larval wormfishes
have inconspicuous pelvic fins. Transforming
eel larvae of many families may superficially
resemble larval microdesmids, but the
eels do not have a normal caudal fin
as do the microdesmids and chaenopsids. |
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| | Diagnosis:
The modal fin-ray count of D-XIII,31-32 (XII-XIV,30-34) A-30-31 (28-33)
indicates Cerdale floridana. (U) md2 |
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Analogues: | |
| Description:
Body somewhat thick, very long and narrow with a small head and round medium-sized
eye and mouth with a blunt, hooked, and protruding lower jaw. Pectoral fins short
and pelvic fins separate and short. Dorsal and anal fin bases very long, caudal
peduncle very short and relatively wide. The caudal fin has a distinct vertical
row and three lateral rows of caudal fin neuromasts (sensory papillae) and there
are 5-7 procurrent caudal fin rays (5-6 spindly). Very lightly marked, mostly
along the ventral midline: a melanophore at the pelvic fin base (often missing),
followed by a pair of short rows of melanophores diverging from the pelvic fin
base along the side of the abdominal gut strip. There is a row of melanophores
along the base of the anal fin rays after the first three (paired and one per
ray), becoming more disassociated from the anal fin base and more variable in
number and depth at the last several rays and continuing into the ventral caudal
peduncle ending at the start of the lower procurrent caudal fin rays. A few scattered
melanophores sometimes extend out along the lower segmented caudal fin rays. A
rare individual has a surface melanophore on the lateral aspect of the caudal
peduncle (a characteristic of larval Microdesmus
spp.), although it is off-center from the lateral midline. Dorsal markings
consist of a few off-center and variably-paired melanophores at the base of some
posterior dorsal fin rays continuing onto the dorsal caudal peduncle ending at
the start of the upper procurrent caudal fin rays. Some larvae have a melanophore
at the angle of the jaw. Internal melanophores occur around the saccule and along
the dorsal surface of the swim bladder (not at the vent). | |
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| Cerdale floridana
larva | | 18.9 mm SL | | San
Blas, Panama, SB86-1001 | |  | | |  | | |  | | |  |
| Cerdale floridana
larva | | 19.0 mm SL | | head
neuromasts | | San Blas, Panama, SB86-1001 |
|  |
| Cerdale floridana
larvae | | 19.0 and 18.9 mm SL |
| dorsal view of caudal peduncle (below) |
| San Blas, Panama, SB86-1001 | |  | | |  |
| Cerdale floridana
larva | | 19.4 mm SL | | lateral
caudal peduncle melanophore | | San Blas,
Panama, SB87-101 | |  |
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| | Diagnosis:
The fin-ray count range of D-IX-XII,26-30 A-24-28 indicates Microdesmus
bahianus. (U) | |
| Analogues:
| |
| Description:
Body somewhat thick, very long and narrow with a small head and round medium
eye and mouth with a hook-like protruding lower jaw with a bulbous tip. |
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| | Diagnosis:
The fin-ray count range of D-XXV-XXVII,43-45 A-36-37 indicates Microdesmus
carri. This is the only Caribbean microdesmid with more than 23 dorsal
fin spines. (U) | |
| Analogues:
| |
| Description:
Body somewhat thick, very long and narrow with a small head and small to
medium-sized round eye and a large mouth with a hook-like protruding lower jaw
with a bulbous tip. Pectoral fins short and pelvic fins separate and short. Dorsal
and anal fin bases very long, caudal peduncle very short and relatively wide,
5-6 procurrent caudal fin rays (5 spindly). Lightly marked, mostly along the ventral
midline: melanophores at the isthmus, a short row of about four just forward of
the pelvic fin base continuing as a short row behind the pelvic fin base then
diverging into a pair of rows along the sides of the abdominal gut strip. There
is a row of melanophores along the base of all of the anal fin rays (paired and
one per ray) continuing as a short row of about three melanophores along the ventral
caudal peduncle midline ending before the procurrent caudal fin rays. There are
melanophores along the base of some of the last dorsal fin rays (paired, off-center,
and one per ray) continuing along the dorsal caudal peduncle midline ending before
the procurrent caudal fin rays. There is a short row of about three melanophores
along the lateral midline of the caudal peduncle. Melanophores line the proximal
third of the lower central caudal fin rays and the mid- and distal portion of
the several lowest segmented caudal fin rays. Melanophores on the head are limited
to a pair at the angles of the jaw. Internal melanophores occur around the saccule
and along the dorsal surface of the swim bladder (not at the vent). |
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| Microdesmus carri
larva | | 30.3 mm SL | | San
Blas, Panama, SB86-1103 | |  | | |
 | | |  |
| Microdesmus carri
larva | | 30.4 mm SL | | San
Blas, Panama, SB86-701 | |  |
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|
| | Diagnosis:
The fin-ray count range of D-XI-XIII,51-61 A-48-56 indicates Microdesmus
lanceolatus .(U) | |
| Analogues:
Content goes here | |
| Description:
Body somewhat thick, long and narrow with a small head and round eye, small
mouth and hook-like protruding lower jaw with a bulbous tip. | |
| |
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| | Diagnosis:
The fin-ray count range of D-XIX-XXIII,40-58 A-36-52 indicates Microdesmus
longipinnis. (U) | |
| Analogues:
| |
| Description:
Body somewhat thick, long and narrow with a small head and round eye, small
mouth and hook-like protruding lower jaw with a bulbous tip. | |
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| | Diagnosis:
The fin-ray count range of D-XII-XIII,37-38 A-35 indicates Microdesmus
luscus. md5(U) | |
| Analogues:
| |
| Description:
Body somewhat thick, very long and narrow with a small head and small round
eye and medium-sized mouth with only a slightly protruding lower jaw. Pectoral
fins short and pelvic fins separate and short. Dorsal and anal fin bases very
long, caudal peduncle very short and relatively wide, 5-6 procurrent caudal fin
rays (5 spindly). Lightly marked, mostly along the ventral midline: melanophores
at the isthmus, just forward of the pelvic fin base and just behind the pelvic
fin base diverging into a pair of short rows along the side of the abdominal gut
strip. There is a row of melanophores along the base of all of the anal fin rays
(paired and one per ray), becoming more disassociated from the anal fin base and
more variable in number and depth at the last several rays and continuing along
the ventral caudal peduncle midline ending under the first lower procurrent caudal
fin ray. There are melanophores along the base of the last two dorsal fin rays
(paired, off-center, and one per ray), and continuing along the dorsal caudal
peduncle midline ending under the first upper procurrent caudal fin ray. There
are one or two discrete large melanophores along the lateral midline of the caudal
peduncle. Melanophores line the proximal third of the lower central caudal fin
rays and the full length of the several lowest segmented caudal fin rays. Melanophores
on the head are limited to a pair at the angles of the jaw. Internal melanophores
occur around the saccule and along the dorsal surface of the swim bladder (not
at the vent). | | |
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| Microdesmus luscus
larva | | 22.3 mm SL | | San
Blas, Panama, SB87-101 | |  | | |
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| All contents
© copyright 2006-2009 Benjamin Victor.
All rights reserved. |
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