|
|
|
|
Group 4: The long-fin gobies
|
| |
|
Evermannichthys, Evorthodus, Ctenogobius, Gnatholepis, Nes,
Bollmannia, Gobionellus,
Gobioides, Microgobius,
and Palatogobius
|
|
| Gobies
with 12 or more dorsal and anal-fin rays have
a generally different look from the short-fin
gobies; they are more likely to have a long
tapering body and a relatively short caudal
peduncle. Although uncommonly encountered
by divers, these gobies are abundant on sand
and silt bottoms near reefs and in brackish
waters along the coast. One species, the Goldspot
Goby Gnatholepis thompsoni, is
commonly seen on the reef. The long-fin gobies
mostly comprise those species that live on
soft substrates, often in holes, and sometimes
with symbiotic shrimp partners. The high number
of fin rays and long narrow bodies are likely
adaptations to hole-dwelling. Their larvae
are typically lightly marked and relatively
small, thin, and long. Those species with
characteristically blunt heads and subterminal
mouths have larvae with pointed snouts and
terminal mouths which undergo marked head-shape
changes at transition. |
|
|
|
| |
| |
| |
|
| Evermannichthys metzelaari | |
| | | | | |
|
| Diagnosis:
This genus of long eel-like sponge gobies
have normally-proportioned larvae. The genus has
notably reduced fin ray numbers: fewer and variable
first-dorsal-fin spine numbers (four to seven),
many fewer pectoral-fin rays (11-13), and only 3-4
procurrent caudal-fin rays. In addition, they have
large spiny scales along the ventral midline of
the caudal peduncle. Fortunately the characteristic
caudal peduncle scales are prominent on larvae (of
E. metzelaari) and confirms the identification.
Risor
ruber, another sponge goby, also has large
spiny scales alogn the ventral midline of the caudal
peduncle, but has many more pectoral-fin rays. There
are five Caribbean species and the number of fin
rays in this genus varies more than usual, often
plus or minus two rays around the mode: Evermannichthys
metzelaari has a modal fin-ray count of D-IV,15
A-12 Pect-12; E. silus
has D-VI-VII,12-13 A-10-11 Pect-13; E.
convictor has D-V,11-13 A-9-11 Pect-13; E.
spongicola (Gulf of Mexico only?) has D-VI-VII,13
A-10-11 Pect-12; and E.
bicolor has a mode of D-VI,11 A-9. |
|
| Description:
Body relatively thin, long, and narrow with a medium
eye, pointed snout, and a large terminal mouth.
Pectoral fins short, pelvic fins long, reaching
almost to the vent. Dorsal and anal-fin bases medium,
caudal peduncle short and narrow with only 3-4 (three
spindly) procurrent caudal-fin rays. Very lightly
marked: internal melanophores at the dorsal surface
of the swim bladder and one melanophore on the caudal
peduncle just after the last anal-fin ray, often
deep and indistinct. There are three or four large
ctenoid scales along the ventral midline of the
caudal peduncle extending from the last anal-fin
ray to the start of the caudal-fin procurrent rays.
Each spiny scale has two large rear-pointing tines
and are outlined in black pigment. Eye shapes range
from a slightly narrowed vertical oval to round.
|
| |
|
| Evermannichthys
metzelaari larva |
| 6.4 mm SL |
| D-V,15 A-14 |
| San Blas, Panama, SB86-608 |
|
 |
| |
 |
| |
 |
| Evermannichthys
metzelaari larva |
| 6.3 mm SL |
| D-V,15 A-14 |
| San Blas, Panama, SB86-808 |
|
 |
|
|
 |
| | |
| |
|
|
|
| Diagnosis:
Modal fin-ray counts of D-VI,11 A-12 and Pect-16-17
indicate Evorthodus
lyricus as well as Ctenogobius
boleosoma and C. smaragdus. These
genera typically have one more anal-fin ray than
second-dorsal-fin rays. This larval type has a short
pelvic fin, extending less than half the way to
the vent, separating it from C.
boleosoma. A larval type that is very similar
to this type occurs in the eastern Pacific region
with fin-ray counts matching only to the sibling
species Evorthodus
minutus (also D-VI,11 A-12; there are no
eastern Pacific Ctenogobius
with this fin-ray count). G12 (DNA) |
|
| Description:
Body thin, long, and narrow with a small pointed head, a small to medium-sized
eye and a terminal medium-sized mouth. The widest part of the body is clearly
at the level of the origin of the anal fin. Pelvic and pectoral fins medium length,
reaching less than half-way to the vent. Dorsal and anal-fin bases relatively
long, caudal peduncle short and narrowing rapidly, procurrent caudal-fin rays
( spindly). Lightly marked mostly along the lower body: melanophores along the
ventral midline sometimes at the isthmus, rarely at the pelvic-fin insertion,
and then, most frequent, another just behind the pelvic-fin insertion. There is
sometimes a row of melanophores along the anal-fin base, variably present and
variably paired (usually only 4 to 7 per side, can occur on either side unpaired),
and sometimes one or a few extending along the ventral midline of the caudal peduncle
ending before the start of the procurrent caudal-fin rays. Many individuals, however,
show only indistinct melanophores or no surface melanophores at all. Melanophores
on the head occur along the upper edge of the anterior premaxilla (often paired),
sometimes also just below the tip of the dentary and along the sides of the lower
jaw as well. Internal melanophores are present around the saccule, the dorsal
surface of the swim bladder, and sometimes around the gut near the vent. Some
individuals have a deep melanophore above the pelvic girdle between the thoracic
and abdominal cavities. Some individuals have paired linear patches of tiny surface
melanophores along the side of the abdomen just forward of the vent. The eyeball
in this larval type shows an unusual variety of shapes, with the small eyeball
often not round, but irregular with tilts in all directions, the iris sometimes
off-center, and indentations of the iris in a number of orientations. Series of
transitional larvae show the eye usually developing from a small slightly narrowed
vertical oval to round and the head shape changing from a pointed snout to a somewhat
blunted profile. Transitional larvae develop melanophores in front of the eye
and over the upper iris, becoming a stripe from the eye to the tip of the upper
jaw. In addition, they develop a straight-line bar across the top of the head
behind the eyes, a large melanophore behind the eye and a row of discrete, often
dendritic, melanophores on the sides of the abdomen just behind the pelvic-fin insertion. | | |
|
| Evorthodus
lyricus larva |
| 8.8 mm SL |
| lightly marked |
| San Blas, Panama, SB84-522 |
|
 |
| |
 |
| |
 |
| Evorthodus
lyricus larva |
| 8.1 mm SL |
| San Blas, Panama, SB84-917 |
|
 |
Evorthodus
lyricus larva (above) vs.
Ctenogobius
boleosoma larva (below) |
| 8.3 and 8.2 mm SL |
| note smaller eye and
shorter pelvic fin |
| San Blas, Panama, SB86-1103 |
|
 |
| Evorthodus
lyricus larva |
| 8.3 mm SL |
| small irregular eye |
| San Blas, Panama, SB87-123 |
|
 |
| Evorthodus
lyricus larva |
| 7.9 mm SL |
| patches of tiny melanophores
near vent |
| San Blas, Panama, SB84-522 |
|
 |
| Evorthodus
lyricus larva |
| 8.3 mm SL |
| patches of tiny melanophores
near vent |
| San Blas, Panama, SB86-1001 |
|
 |
| |
 |
Evorthodus
lyricus
early transitional larva |
| 8.4 mm SL |
| San Blas, Panama, SB86-412 |
|
 |
| |
 |
| |
 |
| Evorthodus
lyricus transitional larva |
| 8.5 mm SL |
| San Blas, Panama, SB86-1029 |
|
 |
| |
 |
| |
 |
| Evorthodus
lyricus transitional recruit |
| 10.9 mm SL |
| Colon, Panama, N7529a |
|
 |
| | |
| |
|
|
| Diagnosis:
Modal fin-ray counts of D-VI,11 A-12 and Pect-16-17
indicate Ctenogobius
boleosoma, C. smaragdus, and Evorthodus
lyricus. These genera typically have one
more anal-fin ray than second-dorsal-fin rays. C.
smaragdus occurs in Florida and Cuba, as well
as Venezuela to Brazil and thus is not included
in this larval type. (DNA) |
|
| Analogues:
(post-anal-fin solitary melanophore, large: >9
mm SL) Metamorphic melanophores comprising an
oblique bar forward of the eye to the mid-upper
jaw and pelvic fins almost reaching the vent confirms
C. boleosoma.
A bar from the iris to the corner of the mouth indicates
C.
saepepallens. Evorthodus
lyricus has a markedly shorter pelvic fin
than C. boleosoma
(or C.
saepepallens) and a more appropriate larval
type is identified for that species. Pre-transitional
larvae of this C. boleosoma
type are distinct in having a solitary melanophore
at the tip of the lower jaw, but those without the
spot would be indistinguishable from pre-transitional
C.
saepepallens (since there is some overlap
in fin-ray counts). This conclusion is based on
the fact that larvae in which that is the sole head
marking usually have 12 anal-fin elements and thus
likely represent C.
boleosoma (C.
saepepallens has a mode of 13 anal-fin elements) |
|
| Description:
Body thin, long, and narrow with a large eye and
a terminal medium-sized mouth. Pectoral fins medium
length, reaching about two-thirds of the way to
the vent (longer at transition). Pelvic fins long
and fused with a clear frenum, reaching much of
the way to the vent. Dorsal and anal-fin bases long,
caudal peduncle relatively short and narrow. The
s-shaped gut is usually clearly visible through
the ventral abdominal wall. Lightly marked mostly
along the lower body: melanophores along the ventral
midline at the isthmus (often missing), at the pelvic-fin
insertion, and then sometimes another just behind
the pelvic-fin insertion, after which some individuals
develop a row on each side of the gut strip along
the abdomen. There are several discrete large melanophores
along the anal-fin base, often variably present
and variably paired (usually only 3-4 per side,
but can be up to 7; can occur on either side unpaired),
and a prominent and characteristic melanophore (rarely
two) at the ventral midline of the caudal peduncle
after the last anal-fin ray which has an internal
extension reaching up towards the lateral midline.
In many individuals, especially earlier-stage larvae,
some melanophores are missing or indistinct and
even the characteristic deep peduncle melanophore
is often not visible. Head markings typically develop
as a melanophore between the mid-upper jaw and eye
(any melanophores extending from the eye to the
corner of the mouth or a solitary melanophore on
the iris surface at that quadrant indicate C.
saepepallens; transitional C.
boleosoma do have melanophores on the lower
iris, but always in combination with other transitional
melanophores). Most pre-transitional larvae have
a solitary melanophore at the tip of the lower jaw,
but whether this is a rule is unclear since some
variant transitional larvae recognizable as C.
boleosoma are missing this melanophore. Internal
melanophores are present around the saccule, the
dorsal surface of the swim bladder, and around the
gut near the vent: Some individuals have a deep
melanophore above the pelvic girdle between the
thoracic and abdominal cavities. Series of transitional
larvae show development of the eye from a slightly
narrowed vertical oval to distinctly larger and
round, often with a dorsal dent in the iris that
sometimes persists into the transitional phase.
The head profile develops from a thin pointed head
to a blunt snout with a particularly bulbous head
compared to the midsection. Transitional larvae
develop a pattern of discrete melanophores on the
jaw and the head (primarily in a stripe forward
of the eye and in pairs on top of the head) and
patches of characteristic tiny leukophores (clearly
smaller and more numerous than on C.
saepepallens) on the upper iris, on top
of the head, and in a stripe forward across the
nasal region and along the upper jaw. Patches of
melanophores then develop along the dorsal midline
and on the lateral midline of the caudal peduncle.
Transitional recruits develop additional specklings
of melanophores, leukophores, and iridophores and
a prominent row of lateral midline blotches. A conspicuous
black spot develops at the base of the upper pectoral-fin
rays. |
|
|
| Ctenogobius
boleosoma larva |
| 8.0 mm SL |
| note internal thoracic
melanophore |
| San Blas, Panama, SB86-701 |
|
 |
| |
 |
| Ctenogobius?
larva |
| 6.4 mm SL |
| internal melanophore
bars, D-VI,11 A-12 |
| Yucatan, Mexico, 240306 |
| coll. by Lourdes Vasquez
et al. |
|
 |
|
|
 |
| Ctenogobius
boleosoma larva |
| 8.2 mm SL |
| San Blas, Panama, SB83-156 |
|
 |
Ctenogobius
boleosoma
early transitional larva |
| 8.9 mm SL |
| melanophore pattern |
| San Blas, Panama, SB83-137 |
|
 |
| |
 |
Ctenogobius boleosoma (above) vs.
C.
saepepallens (below) transitional
larvae |
| 8.8 and 8.9 mm SL |
| note leukophore size
differences |
| San Blas, Panama, SB86-809 |
|
 |
| Ctenogobius
boleosoma transitional larva |
| 8.3 mm SL |
| tiny leukophores |
| San Blas, Panama, SB87-218 |
|
 |
| Ctenogobius
boleosoma transitional larvae |
| 8.6 and 8.4 mm SL |
| variant below without
tip-of-lower-jaw spot |
| San Blas, Panama, SB86-1103 |
|
 |
Ctenogobius
boleosoma
late transitional larva |
| 9.9 mm SL |
| indistinct leukophores |
| San Blas, Panama, SB86-1002 |
|
 |
Ctenogobius
boleosoma
late transitional larva |
| 9.0 mm SL |
| persistent dorsal iris
indentation |
| San Blas, Panama, SB86-929 |
|
 |
| |
 |
Ctenogobius
boleosoma
late transitional larva |
| 8.8 mm SL |
| San Blas, Panama, SB83-123 |
|
 |
| Ctenogobius
boleosoma recruit
|
| 9.6 mm SL, pale sand morph |
| St. Thomas, USVI, ST506 |
|
 |
| |
 |
| Ctenogobius
boleosoma recruit |
| 11.1 mm SL, dark inshore morph |
| Colon, Panama, N7528b |
|
 |
|
|
 |
| | |
| |
|
|
| Diagnosis:
Modal fin-ray counts of D-VI,12 A-13 and Pect-16-17
indicate Ctenogobius
species. These species typically have one more
anal-fin ray than second-dorsal-fin rays. There
are a number of species that are widespread and
occupy different habitats and some freshwater and
brackish species with more restricted ranges. Eight
of the ten species share the median-fin ray count.
Ctenogobius saepepallens
occurs abundantly around reefs and in mangroves
and is the most common fish larva collected over
reefs in Panama. Turbid-water species include C.
boleosoma (with modal 11/12), C.
stigmaticus (Pect. 18), and C.
stigmaturus (Pect. 16). Fresh-water and brackish
species include C.
fasciatus (Pect. 17-18), C.
pseudofasciatus, C.
claytonii (Pect. 15-17) in the S. Gulf of
Mexico, C. phenacus,
found from Venezuela south, and C.
shufeldti (Pect. 17-18) in Florida/Gulf of
Mexico and Venezuela to Brazil. The related Oxyurichthys
stigmalophius has more fin rays: D-VI,13
A-14 and many more (21-22) pectoral-fin rays. Vomerogobius
flavus is a deep-water goby from the Bahamas
with similar fin-ray counts (D-VI,12-13 A-13 pect-15-16),
but it has a distinctly large eye and no pelvic
frenum. (DNA) |
| Transitional
larvae and juveniles with a bar from the iris to
the corner of the mouth indicates C.
saepepallens (but the others may not be excluded).
Transitional larvae and juveniles with an oblique
bar forward of the eye to the mid-upper jaw and
not at the corner of the mouth indicate C.
boleosoma. |
| Description:
Body thin, long, and narrow with a large eye and a terminal medium to small
mouth. Pectoral fins medium length, reaching about two-thirds of the way to the
vent (longer at transition). Pelvic fins long and fused with a clear frenum, reaching
much of the way to the vent. Dorsal and anal-fin bases long, caudal peduncle relatively
short and narrow. The s-shaped gut is usually clearly visible through the ventral
abdominal wall. Lightly marked mostly along the lower body: melanophores along
the ventral midline at the isthmus (often missing), at the pelvic-fin insertion,
and then sometimes another just behind the pelvic-fin insertion, after which some
individuals develop a row on each side of the gut strip along the abdomen. There
are several discrete large melanophores along the anal-fin base, often variably
present and variably paired (usually only 3-4 per side, but can be up to 7; can
occur on either side unpaired), and a prominent and characteristic melanophore
at the ventral midline of the caudal peduncle after the last anal-fin ray (rarely
two) which has an internal extension reaching up towards the lateral midline.
In many individuals, especially earlier-stage larvae, some melanophores are missing
or indistinct and even the characteristic peduncle melanophore is often not visible.
The head is unmarked prior to transition, but many individuals show a characteristic
melanophore on the iris at about 7 o'clock, often with an additional melanophore
extending to the corner of the mouth. Larvae that have a melanophore just before
the tip of the lower jaw, especially when that is the sole head marking, usually
also have 12 anal-fin elements and are thus likely C.
boleosoma. However, some transitional larvae of this
C. saepepallens type have that melanophore, but typically along with many
other head markings. Internal melanophores are present around the saccule, the
dorsal surface of the swim bladder, and around the gut near the vent: some individuals
have a deep melanophore above the pelvic girdle between the thoracic and abdominal
cavities. Series of transitional larvae show development of the eye from a slightly
narrowed vertical oval to distinctly larger and round, often with a dorsal dent
in the iris that sometimes persists into the transitional phase. The head profile
develops from a thin pointed head to a blunt snout with a particularly bulbous
head compared to the midsection. Transitional larvae develop a scattering of iridophores
and leukophores on the head along with a pattern of a few discrete large melanophores
on the head behind the eye and at the base of the pectoral fins. The leukophores
on the top of the head are few, large, and scattered compared to those on the
head of transitional C. boleosoma
larvae. The characteristic bar below the eye further develops with more melanophores
extending to the corner of the mouth. Melanophores develop in patches spaced out
along the base of the dorsal fin, at the end of the caudal peduncle and at the
base of the central caudal-fin rays. Transitional recruits develop additional
specklings of melanophores and leukophores and a lateral midline row of melanophore
patches. A black spot develops at the base of the upper pectoral-fin rays. |
| |
|
| Ctenogobius saepepallens
larva | | 10.1 mm SL |
| San Blas, Panama, SB86-921 | | |
|  |
| Ctenogobius saepepallens
larva | | 10.0 mm SL |
| San Blas, Panama, SB86-627 | |  |
| Ctenogobius saepepallens
larva | | 9.2 mm SL |
| San Blas, Panama, SB86-815 | |  |
| Ctenogobius saepepallens
larvae | | 8.1 to 9.5 mm SL |
head shape and eye development,
melanophore variation |
| San Blas, Panama, SB83-151 | |  |
| Ctenogobius saepepallens
larva | | 9.9 mm SL |
| pelvic frenum, abdominal melanophores |
| San Blas, Panama, SB86-623 | |  | | |  |
| Ctenogobius saepepallens
larvae | | 9.2 and 9.3 mm SL |
| S-shaped gut, melanophore variation |
| San Blas, Panama, SB86-623 | |  |
| Ctenogobius saepepallens
+ larva | | 6.7 mm SL |
| small but not early stage, eye is round |
| San Blas, Panama, SB86-502 | |  | | |  |
| Ctenogobius saepepallens
+ larva | | 7.8 mm SL |
| small with indistinct melanophores | | San
Blas, Panama, SB84-529a | |  | | |  |
| Ctenogobius saepepallens
larva | | 9.1 mm SL |
| melanophores indistinct or absent | | San
Blas, Panama, SB84-520 | |  | | |  |
Ctenogobius saepepallens
early transitional larva | | 9.9
mm SL | | deep caudal peduncle melanophore |
| San Blas, Panama, SB86-409 | |  |
Ctenogobius saepepallens
early transitional larva | | 9.6
mm SL | | leukophores and iridophores only |
| San Blas, Panama, SB84-624a | |  |
Ctenogobius saepepallens
transitional larva | | 9.0 mm SL |
| San Blas, Panama, SB84-405 | |  | | |  |
Ctenogobius saepepallens
transitional larva | | 9.5 mm
SL | | San Blas, Panama, SB87-218 |
|  | | |  |
Ctenogobius saepepallens
transitional larvae | | 9.3, 9.3, and
9.0 mm SL | | head melanophore
variation | | San Blas, Panama, SB86-405 |
|  | | |  |
Ctenogobius saepepallens
early transitional larvae | | 8.7 and
9.7 mm SL | | eye changes |
| San Blas, Panama, SB87-218 | |  |
Ctenogobius saepepallens
transitional recruit | | 9.4 mm SL |
| San Blas, Panama, SB82-097 |
|  | | |  |
| Ctenogobius saepepallens
juvenile | | 15.7 mm SL |
| San Blas, Panama, SB83-111 |
|  |
| | |
| |
|
|
| Diagnosis:
Modal fin-ray counts of D-VI,12 A-12 Pect-17 indicate
Gnatholepis thompsoni.
(DNA) |
|
| Analogues:
(long, and narrow, no anal-fin base row of melanophores)
Similar median-fin ray counts occur in Bollmannia
litura, but that genus has seven first-dorsal-fin spines and many more pectoral-fin rays (20 or
more). Rare individuals of Ctenogobius
saepepallens , and probably others of that
genus, can have equal numbers of anal and second-dorsal-fin ray elements and thus match the counts
of this larval type. Most long, and narrow larval
gobies have a row of melanophores along the anal-fin base, but among some groups there are often
individuals without markings (primarily Ctenogobius
spp. and Evorthodus
lyricus). Those individuals can resemble
larval Gnatholepis thompsoni, but usually
have one more anal-fin element than second-dorsal-fin elements vs. equal numbers in Gnatholepis
thompsoni larvae. In addition, larval Gnatholepis
thompsoni have a distinctly larger eye, a smaller
downturned mouth, and melanophores along the dorsal
fins. The transitional melanophore patterns are
also completely different. Larval Evermannichthys
spp. have a larger mouth, a sharply-pointed
snout, and spiny caudal peduncle scales. |
|
| Description:
Body thin, long, and narrow with a large eye and relatively small somewhat downturned
mouth. Pectoral fins medium length, pelvic fins medium length and fused with a
clear frenum, dorsal and anal-fin bases long, caudal peduncle relatively long
and somewhat narrow. Pretransitional larvae have melanophores only on the dorsal
fins, along the membranes between the dorsal-fin spines and the first three or
four second-dorsal-fin elements (these can be missing on larvae with frayed fins).
Series of transitional larvae show the eye remaining large and round, often with
a prominent dorsal, occasionally a ventral, indentation in the iris. Transitional
larvae develop a melanophore on the proximal middle pectoral-fin rays and rows
of large melanophores on the body near the base of the dorsal fins. The characteristic
comma-shaped bar below the eye then develops from the iris down and a corresponding
bar develops on the upper iris onto the dorsal surface of the head. Leukophore
patches form over the top of the head and over the iris, on the cheek, and on
the base of the pectoral fin. | | |
|
| Gnatholepis
thompsoni transitional larva |
| 9.9 mm SL |
| San Blas, Panama, SB84-624a |
| |
|
 |
| Gnatholepis
thompsoni transitional recruit |
| 10.3 mm SL |
| Colon, Panama, N7529b |
| |
|
 |
| |
 |
| | |
| |
|
|
| Diagnosis:
Modal fin-ray counts of D-VII,13 (or 14) A-11 (to
13) Pect. 17 indicate Nes longus. This species
typically has one or two fewer anal-fin rays than
second-dorsal-fin rays. (DNA) |
|
| Analogues:
(post-anal-fin solitary melanophore, large: >9
mm SL) Within the diverse solitary post-anal-fin
melanophore group, there are few species with large
larvae: the only other large larva comparable to
Nes longus is that of Psilotris
amblyrhynchus. The similarity is especially
notable when larval Nes longus are missing
their anterior anal-fin base melanophores as well
as their caudal-fin base melanophores, which is
not uncommon. In that case, P.
amblyrhynchus larvae can be separated by
pelvic fin morphology (mostly divided pelvic fins
with no frenum vs. fused and an obvious frenum in
Nes longus)
and fewer median-fin rays (usually 12/11 vs. 13-14/11-13).
Other similar goby larvae are much smaller: some
with divided pelvic fins and typically other distinctive
melanophores (Psilotris,
Gobulus
myersi, and Pycnomma
roosevelti) and, with fused pelvic fins
(and usually only the solitary post-anal-fin melanophore),
some Gobiosoma
and Elacatinus,
as well as Evermannichthys
(the latter also with a sharply-pointed snout and
spiny caudal peduncle scales). |
|
| Description:
Body somewhat thick, long, and narrow with a large head and medium-sized eye and
terminal large mouth. Pectoral fins medium length, not reaching to the level of
the vent, pelvic fins medium length as well and fused with a clear frenum. Dorsal
and anal-fin bases medium length, caudal peduncle relatively long, and narrowing
rapidly. Lightly marked along the lower body: melanophores limited to a streak
in front of the pelvic-fin insertion (often obscure, sometimes absent), a melanophore
or two per side (variably paired) at the base of the anterior anal-fin rays (sometimes
absent, occasionally one more at the mid-anal fin as well), and a large prominent
dendritic melanophore at the ventral midline after the last anal-fin ray (often
spreading over the base of the last anal-fin rays). Internal melanophores are
present above the the rear brain case at the midline, single and often obscured,
along the dorsal surface of the swim bladder and around the gut near the vent
(often dendritic and extending down to the surface around the vent). Many individuals
also have one or two melanophores at the base of one or two of the lower segmented
caudal-fin rays. Series of transitional larvae show development of the eye from
a slightly narrowed vertical oval to round and then, particularly unusual for
gobies, becoming relatively much smaller as the head shape changes. The head widens
and broadens markedly as the body stays relatively narrow and the pelvic fins
become shorter. Transitional larvae develop melanophores in an arc behind the
upper eye, between the eye and the mid-upper jaw, at the angle of the jaw and
below the mid-dentary of the lower jaw. Transitional larvae have a bubblewrap-like
skin. | | |
|
| Nes longus larva |
| 10.7 mm SL | | Carrie
Bow Cay, Belize 1986 | |  | | |  |
| Nes longus larvae |
| both 9.2 mm SL | | note
internal head melanophore | | San Blas, Panama,
SB87-225 | |  |
| Nes longus early
transitional larva | | 9.9 mm SL |
| shorter pelvic fins | | San
Blas, Panama, SB86-929 | |  | | |  | | |  | | |  |
| Nes longus early
transitional larva | | 9.7 mm SL |
| San Blas, Panama, SB81-047 |
|  |
| Nes longus early
transitional larva | | 9.8 mm SL |
| head melanophores, bubblewrap-like skin |
| San Blas, Panama, SB87-225 | |  | | |  | | |  |
| Nes longus transitional
larva | | 9.1 mm SL |
transitional morphology only
head broadens, eye
much smaller | | San Blas, Panama, SB83-163 |
|  | | |  |
| Nes longus transitional
larva | | 9.0 mm SL | | San
Blas, Panama, SB86-1120 | |  |
| | |
| |
|
|
| Diagnosis:
Modal fin-ray counts of D-VII,13 A-13 and
Pect-20-22 indicate Bollmannia
boqueronensis or Parrella
macropteryx. second-dorsal-fin elements 12-15
and anal-fin elements 12-14 with equal numbers of
elements and high pectoral-fin-ray counts are only
found in these two genera (Gobionellus
spp., Gobioides, and Microgobius
all have more than 15 anal-fin elements). Median-fin ray counts are variable in the two genera with
some species having more anal-fin rays than second-dorsal-fin rays. B.
boqueronensis has a mode of 13 second dorsal
and anal-fin elements and 20-21 pectoral-fin rays.
Other regional species comprise B.
litura with 12 second dorsal and anal-fin
elements and 20 pectoral-fin rays, B.
eigenmanni with 12 second dorsal and 13 anal-fin
elements and 23-25 pectoral-fin rays, and B.
communis (USA to Campeche) with a mode of
15 second dorsal and 14 anal-fin elements and 22
pectoral-fin rays. Parrella
macropteryx, the only species of its genus
in the Atlantic, cannot be excluded from the larval
type (D-VII,11-14 A-13, pect. count?). Some other
gobies overlap the median-fin soft ray counts, but
all have six first-dorsal-fin spines:
Oxyurichthys stigmalophius with one more
anal than dorsal-fin rays (D-13 A-14, Pect-21-22),
a few Ctenogobius species
(but they have many fewer pectoral-fin rays), and
Vomerogobius flavus
(D-VI,12-13 A-13, but Pect-15-16). (U) |
|
| Note:
Earlier-stage larvae are somewhat different in appearance and it is not
certain that these types all represent the same species. The fin-ray count is
somewhat distinctive and all specimens share the count. A 7.1 mm SL larva with
stubs of pelvic fins and melanophores in a row along the ventral midline of the
abdomen and on the dorsal midline of the caudal peduncle resembles a larvae identified
as Bollmannia communis by Ruple 2004 (Richards'
goby chapter), but my larva has melanophores at the base of the lower caudal-fin rays not illustrated by Ruple and one fewer dorsal and anal-fin rays. Larger and
transitional specimens, over 9.0 mm SL, are missing the midline abdominal melanophores,
but share with the 7.1 mm SL specimen the fin-ray count, the melanophore at the
angle of the jaw, the speckled membrane above the upper eyeball, the caudal peduncle
melanophore (sometimes) and the large slightly underslung mouth, making it likely
that they represent a single series of Bollmannia
sp. The early-stage 5.9 mm SL larva shares the fin-ray count and the unusual
irregular eye shape with the 7.1 mm SL specimen. | |
| Description:
Body thin, long, and narrow with a large eye and mouth. Pectoral fins long, pelvic
fins long (in larvae above 9 mm SL, stubs in 7.1 mm SL and less), dorsal and anal-fin bases medium length, caudal peduncle long, and narrowing rapidly, 8-9 procurrent
caudal-fin rays (8 spindly). Lightly marked mostly along the ventral midline:
melanophores in streaks at the posterior isthmus and along the pelvic-fin insertion,
then four midline melanophores along the abdomen (only in the 7.1 mm SL larva),
the last just forward of the vent, then a row along the anal-fin base behind the
second anal-fin element (variably paired, one per side) and then a long streak
extending along the ventral midline of the caudal peduncle ending near the start
of the procurrent caudal-fin rays. There are melanophores at the base of some
of the lower segmented caudal-fin rays. The only dorsal marking is a melanophore
on the dorsal midline of the caudal peduncle some distance after the last dorsal-fin ray (missing in some individuals). There are melanophores at the angle of
the jaw in the larvae over 7.0 mm SL. There are internal melanophores along the
dorsal surface of the swim bladder and around the gut near the vent. The eye is
unusual, ranging from a large irregular oblong tilted forward with a ventral anterior
indentation in the iris and a posterior-inferior iris extension in earlier-stage
larvae becoming a moderately-narrowed vertical oval in the largest larvae. Larvae
over 7 mm SL also have a speckled "eyebrow" membrane over the upper third of the
eyeball that appears detached from the pigmented iris below. | |
|
|
| Bollmannia boqueronensis
? larva | | 5.9 mm SL |
| earlier stage larva | | San
Blas, Panama, SB84-522 | |  | | |  |
| Bollmannia boqueronensis
larva | | 7.1 mm SL |
second dorsal with 12, A-13 elements
pectoral fin
incomplete but >20 | | San Blas, Panama, SB86-1006 |
|  | | |  | | |  | | |  |
| Bollmannia boqueronensis
larva | | 9.3 mm SL |
| San Blas, Panama, SB82-044 | |  | | |  |
| Bollmannia boqueronensis
larvae | | 9.3 and 9.1 mm SL |
| San Blas, Panama, SB82-044 |
|  |
| Bollmannia boqueronensis
larva | | 9.1 mm SL |
| note speckled eyebrow membrane |
| San Blas, Panama, SB82-044 | |  |
| Bollmannia boqueronensis
larva | | 9.4 mm SL |
| note dorsal caudal peduncle spot |
| San Blas, Panama, SB81-001 | |  |
| | |
| |
|
| | Diagnosis:
Modal fin-ray counts of D-VI,14 and A-15 indicate Gobionellus
oceanicus. This genus typically has one more anal-fin ray than second-dorsal-fin rays (sometimes equal). A number of other species have spent some time in
this genus, but Pezold 2004 recognizes only one Caribbean species. (U) G9 |
| | Description:
Body thin, very long, and narrow with a small eye and a pointed snout with a terminal
large mouth. Pectoral and pelvic fins long relative to the head (but short compared
to the long body), extending more than halfway to the vent. Dorsal and anal-fin
bases very long, caudal peduncle short, . Lightly marked along the lower body:
melanophores usually in streaks at the isthmus (often missing) and at the pelvic-fin insertion, internally at the dorsal surface of the swim bladder and around
the gut near the vent, and in a row along the anal-fin base, often variably present
and variably paired (can occur on either side unpaired). In many individuals the
surface melanophores are indistinct or some are missing. Series of transitional
larvae show development of the eye from a markedly narrowed vertical oval with
a flattened base, the pupil off-center dorsally, and a pronounced slant backwards
to large and round. The head profile develops from a thin pointed head to a blunt
snout with an almost sub-terminal mouth. Transitional larvae first develop patches
of tiny iridophores on the top of the head and in a stripe behind the eye and
then a scattering of large discrete melanophores on the head. Body markings include
a lateral row of melanophores on each side of the gut strip along the abdomen.
Melanophores develop in patches spaced out along the base of the dorsal fin, on
the caudal peduncle, and at the base of the central caudal-fin rays. |
| |
|
| Gobionellus oceanicus larva |
| 12.5 mm SL | | note
eye tilted sharply backward | | San Blas,
Panama, SB81-002 | |  |
Gobionellus oceanicus
larva above
vs. Microgobius signatus
below | | 13.4 mm SL |
| San Blas, Panama, SB86-528 | |  |
Gobionellus oceanicus
early transitional larva | | 13.3 mm SL |
| San Blas, Panama, SB86-728 |
|  |  | | |  |
| Gobionellus oceanicus
transitional larva | | 13.4 mm SL |
| San Blas, Panama, SB86-405 |
|  | | |  |
| Gobionellus oceanicus
transitional larva | | 12.9 mm SL |
| San Blas, Panama, SB86-1103 |
|  | | |  | | |  |
| Gobionellus oceanicus
transitional larva | | 12.7 (above) and 12.9
mm SL | | San Blas, Panama, SB86-1103 |
|  |
| Gobionellus oceanicus
transitional larva | | 12.8 mm SL |
| San Blas, Panama, SB86-929 |
|  | | |  |
| | |
| | |
|
| | Diagnosis:
Modal fin-ray counts of D-VI (last two longest),15-16 A-16-17 and Pect-18-19
and continuous dorsal fins, small eye and short pectoral and pelvic fins indicate
Gobioides broussonnetii. G. grahamae occurs
in Guyana south to Brazil. Akko dionaea, an
obscure mud-bottom brackish-water goby found at the mouth of large rivers in Colombia
and Brazil, has D-VII,15 A-15 Pect-16-18. | |
| |
| |
| | |
| |
|
|
| Diagnosis:
Modal fin-ray counts of D-VII,16-17 (15-18)
A-16-17 (16-19) and Pect-20-24 are shared by several
Microgobius species: M.
carri and M.
meeki (widespread in the Caribbean) and M.
gulosus (D-VII,15-17 A-16-18 and Pect-20-23)
and M. thalassinus
(D-VII,15-17 A-16-17 and Pect-20-22) found in temperate
US waters and the Gulf of Mexico only. This genus
typically has one more anal-fin ray than dorsal-fin rays (but often equal numbers). (ML) |
|
| Description:
Body thin, long, and narrow with a large eye and a terminal mouth. Pectoral fins
short, pelvic fins stubs until transition, dorsal and anal-fin bases very long,
caudal peduncle very short and narrow, 7-9 procurrent caudal-fin rays (7-8 spindly).
Lightly marked along the lower body: melanophores usually in long streaks at the
posterior isthmus, at the pelvic-fin insertion and then continuing as an abdominal
midline streak ending about half way between the pelvic-fin insertion and the
swim bladder (vs. eleotrids
where it extends to the swim bladder). There is a row of melanophores along the
anal-fin base (variably paired, one per side, a few larger ones starting at the
second or third element that are fewer than one per ray, then becoming small and
usually one per ray), and then a streak along the ventral midline of the very
short caudal peduncle ending at the start of the procurrent caudal-fin rays. Melanophores
are present on some of the anal-fin ray membranes, usually between the first six
elements near the base of the ray (the frequency of occurrence of the anal-fin
ray membrane melanophores is uncertain since many larvae have frayed fin rays).
Melanophores are present at the base of most of the lower segmented caudal-fin rays extending a short way out along the rays; in larger individuals there are
melanophores at the base of the central and some of the upper segmented caudal-fin rays as well. Some larger larvae have melanophores at the angle of the jaw
and around the sacculus, but on many larvae these are absent. Internal melanophores
are present at the dorsal surface of the swim bladder and often around the gut
near the vent. Size series of larvae show variable eye shapes: at around 6 mm
SL the eye is round with dorsal and ventral indentations in the iris and a posterior-inferior
exension of the iris, then between 7 and 11 mm SL the eye is a somewhat-narrowed
vertical oval, often tilting slightly forward, with a prominent posterior-inferior
extension of the iris. At transitional sizes (11-15 mm SL), larvae develop large
round eyes. Many larvae have a speckled "eyebrow" membrane over the upper third
of the eyeball that appears detached from the pigmented iris below. Transitional
larvae develop internal melanophores within the caudal peduncle and the pelvic
fins extend in length rapidly. A melanophore appears behind the upper edge of
the operculum above a streak of iridophores. Transitional recruits develop a stripe
from the eye to the caudal peduncle and speckling along the bases of the median-fin rays and a row of melanophores along the lateral wall of the abdomen below
the pectoral fin. | | |
|
| Microgobius carri
transitional larva | | 12.3 mm SL |
| San Blas, Panama, SB1-019 | |  |
| Microgobius carri
transitional larva | | 13.2 mm SL |
| San Blas, Panama, SB6-1120 | |  | | |  |
| Microgobius carri
transitional recruit | | 14.9 mm SL |
| San Blas, Panama, SB82-033 | |  | | |  |
| | |
| |
|
|
| Diagnosis:
Modal fin-ray counts of D-VII,16-17 (15-18)
A-16-17 (16-19) and Pect-20-24 are shared by several
Microgobius species: M.
carri and M.
meeki (widespread in the Caribbean) and M.
gulosus (D-VII,15-17 A-16-18 and Pect-20-23)
and M. thalassinus
(D-VII,15-17 A-16-17 and Pect-20-22) found in temperate
US waters and the Gulf of Mexico only. This genus
typically has one more anal-fin ray than dorsal-fin rays (but often equal numbers). (ML) |
|
| Description:
Body thin, long, and narrow with a large eye and a terminal mouth. Pectoral fins
short, pelvic fins stubs until transition, dorsal and anal-fin bases very long,
caudal peduncle very short and narrow, 7-9 procurrent caudal-fin rays (7-8 spindly).
Lightly marked along the lower body: melanophores usually in long streaks at the
posterior isthmus, at the pelvic-fin insertion and then continuing as an abdominal
midline streak ending about half way between the pelvic-fin insertion and the
swim bladder (vs. eleotrids
where it extends to the swim bladder). There is a row of melanophores along the
anal-fin base (variably paired, one per side, a few larger ones starting at the
second or third element that are fewer than one per ray, then becoming small and
usually one per ray), and then a streak along the ventral midline of the very
short caudal peduncle ending at the start of the procurrent caudal-fin rays. Melanophores
are present on some of the anal-fin ray membranes, usually between the first six
elements near the base of the ray (the frequency of occurrence of the anal-fin
ray membrane melanophores is uncertain since many larvae have frayed fin rays).
Melanophores are present at the base of most of the lower segmented caudal-fin rays extending a short way out along the rays; in larger individuals there are
melanophores at the base of the central and some of the upper segmented caudal-fin rays as well. Some larger larvae have melanophores at the angle of the jaw
and around the sacculus, but on many larvae these are absent. Internal melanophores
are present at the dorsal surface of the swim bladder and often around the gut
near the vent. Size series of larvae show variable eye shapes: at around 6 mm
SL the eye is round with dorsal and ventral indentations in the iris and a posterior-inferior
exension of the iris, then between 7 and 11 mm SL the eye is a somewhat-narrowed
vertical oval, often tilting slightly forward, with a prominent posterior-inferior
extension of the iris. At transitional sizes (11-15 mm SL), larvae develop large
round eyes. Many larvae have a speckled "eyebrow" membrane over the upper third
of the eyeball that appears detached from the pigmented iris below. Transitional
larvae develop internal melanophores within the caudal peduncle and the pelvic
fins extend in length rapidly. A melanophore appears behind the upper edge of
the operculum above a streak of iridophores. Transitional recruits develop a stripe
from the eye to the caudal peduncle and speckling along the bases of the median-fin rays and a row of melanophores along the lateral wall of the abdomen below
the pectoral fin. | | |
|
| Microgobius
meeki larva |
| 12.3 mm SL |
| San Blas, Panama, SB1-019 |
|
|
| | |
| |
|
| | Diagnosis:
Modal fin-ray counts of D-VII,18-19 (16-20) A-19 (18-20) Pect-21-22 indicate
Microgobius microlepis. This genus typically
has one more anal-fin ray than dorsal-fin rays (but often equal numbers). (PE)
G318/19 | | |
| |
| | |
|
| |
|
| | Diagnosis:
Modal fin-ray counts of D-VII,18-19 (16-20) A-19 (18-20) Pect-21-22 indicate
Microgobius microlepis. This genus typically
has one more anal-fin ray than dorsal-fin rays (but often equal numbers). (PE)
G318/19 | | |
| |
| | |
| |
|
|
|
| Diagnosis:
Modal fin-ray counts of D-VII,20 (19-22)
A-21 (20-22) Pect-19-22 indicates Microgobius
signatus and Palatogobius
paradoxus. This genus typically has one
more anal-fin ray than dorsal-fin rays (but often
equal numbers). Ptereleotris
helenae (previously Ioglossus helenae)
has 22 or more second-dorsal-fin elements (along
with only six first-dorsal-fin spines and separate
pelvic fins). (U) |
|
| Description:
Body thin, long, and narrow with a large eye and a large terminal mouth. Pectoral
fins short, pelvic fins stubs, dorsal and anal-fin bases very long, caudal peduncle
very short and narrow, procurrent caudal-fin rays 7-9 (7-8 spindly). Lightly marked
along the lower body: melanophores usually in long streaks at the posterior isthmus,
at the pelvic-fin insertion and then continuing as an abdominal midline streak
ending about half way between the pelvic-fin insertion and the swim bladder (vs.
eleotrids where it extends to the swim bladder). There is a row of melanophores
along the anal-fin base (variably paired, one per side, a few larger ones starting
at the second or third element that are fewer than one per ray, then becoming
small and usually one per ray), and then a streak along the ventral midline of
the very short caudal peduncle ending at the start of the procurrent caudal-fin rays. Melanophores are present on some of the anal-fin ray membranes, usually
between the second and sixth elements, and along the base of some of the lower
segmented caudal-fin rays extending a short way out along the rays. The frequency
of occurrence of the anal-fin ray membrane melanophores is uncertain, since many
larvae have frayed fin rays. Some larger larvae have melanophores at the angle
of the jaw and around the sacculus, but on many larvae, especially smaller specimens,
these are absent. Internal melanophores are present at the dorsal surface of the
swim bladder and often around the gut near the vent. Size series of larvae show
variable eye shapes at early stages: at around 6 mm SL the eye is round with dorsal
and ventral indentations in the iris and a posterior-inferior exension of the
iris, then between 7 and 11 mm SL the eye is a somewhat-narrowed vertical oval,
often tilting slightly forward, with a prominent posterior-inferior extension
of the iris. Some larvae at this stage have unusual outgrowths, extensions, and
distortions of the eyeball. At transitional sizes (11-13 mm SL), larvae develop
large round eyes. Many larvae have a speckled "eyebrow" membrane over the upper
edge of the eyeball that appears detached from the pigmented iris below. The iris
in this genus has a subtle, yet distinctive, "flat" appearance with a more uniform
shine than is present on the eyes of other goby larvae. | |
|
| |  |
| Microgobius sp.larva |
| 6.6 mm SL | | earlier
stage larva | | San Blas, Panama, SB86-502 |
|  | | |  |
| Microgobius sp. ? larva |
| 6.6 mm SL | | thin
variant, with round eye | | San Blas, Panama,
SB84-522 | |  | | |  |
| Microgobius signatus larva |
| 6.3 mm SL | | note
pigmented membrane above eyeball | | San Blas,
Panama SB87-201 | |  |
| Microgobius signatus larva |
| 8.5 mm SL | | note
pigmented membrane above eyeball | | San Blas,
Panama SB87-228 | |  |
| Microgobius signatus larva
| | 8.9 mm SL | | note
melanophore streak onto pelvic fins | | San
Blas, Panama SB86-503 | |  |
| Microgobius signatus larva |
| 9.4 mm SL | | note
pigmented membrane above eyeball | | San Blas,
Panama SB86-1224 | |  |
| Microgobius signatus larva
| | 10.0 mm SL | | San
Blas, Panama SB86-422 | |  |
| Microgobius signatus
larva | | 11.9 mm SL | | San
Blas, Panama, SB86-502 | |  |
| |
| Microgobius signatus larva |
| 8.0 mm SL | bilateral
eye abnormality: intracranial
and extraorbital extension of the eye |
| San Blas, Panama, SB84-624a | |  | | |  |
| Microgobius sp.larva |
| 5.4 mm SL | | earlier
stage larva eye abnormality | | San Blas,
Panama, SB84-526 | |  | | |  |
| | |
| |
|
|
| Diagnosis:
An individual larva with fin-ray counts
of D-VII,21 A-21 Pect-18 indicates Palatogobius
paradoxus and overlaps the range for Microgobius
signatus. The soft dorsal-fin-ray count
for P. paradoxus varies in the literature,
but the upper range often includes 21 elements.
This larval type furthermore shares the particularly
large round eye and long pelvic fins reaching to
the vent with P. paradoxus
(indicative of a deeper-water species), as
well as the fused pelvic fins without a frenum.
The bathydemersal sibling species P.
grandoculus cannot be excluded. Ptereleotris
helenae (previously Ioglossus
helenae) modally has 22 or more second-dorsal-fin elements (and only six first-dorsal-fin spines
and separate pelvic fins). (U) |
|
| Analogues:
(long goby with long dorsal and anal fins)
This larval type has unique markings for the group,
especially a melanophore below the base of the mid-dorsal
fin (in a pre-transitional larva). Body form similar
to Microgobius,
but no anal-fin row of melanophores and a distinctly
longer pelvic fin. |
|
| Description:
Body thin, long, and narrow with a very large eye and a large terminal mouth. Pectoral
fins medium length, pelvic fins long, reaching most of the way to the vent without
an obvious frenum. Dorsal and anal-fin bases long, caudal peduncle short and narrow,
8-9 procurrent caudal-fin rays (8 spindly). Lightly marked; a row of streak melanophores
on the ventral midline from the isthmus to the pelvic-fin insertion and one just
behind the pelvic-fin insertion. There are only two other melanophores on the
body: one at the base of the anal fin around the thirteenth fin element and one
at the dorsal midline below the base of the sixth fin element. There are no markings
on the fins. Internal melanophores are present at the dorsal surface of the swim
bladder and around the gut near the vent. The eye is large and round with a prominent
speckled "eyebrow" membrane over the upper half of the eyeball that appears detached
from the pigmented iris below. | | |
|
| Palatogobius paradoxus
larva | | 9.5 mm SL |
| San Blas, Panama, SB81-019 | | |
|  | | |  | | |  | | |  |
| |
|
| |
|
| |
| All contents ©
copyright 2006-2009 Benjamin Victor. All rights reserved.
|
|
| |
