|
| | Group
3 Gobies | | |
Seven-spined: standard 9,10, and 11
dorsal and anal fin elements
(mostly similar, lightly marked species) |
|
| | This
group includes many of the inconspicuous small gobies on and around Caribbean
reefs which are mostly well-hidden around the reef structure or within large sponges.
The main exception is the group of cleaner gobies that live on prominent coral
heads and sponges and remove parasites from passing fishes. Cleaner gobies need
to advertise and typically have bright blue or yellow stripes on a black background.
The larvae of Group 3 gobies are typically small and lightly marked, usually with
only a ventral midline series of melanophores. These characters are shared by
the six-spined standard gobies of Group
2 and the two groups can be a challenge to separate. Nevertheless, with the
characters discussed here, all should be able to be quickly identified at least
to genus. | | | |
| | |
|
|
| | Diagnosis:
Fused pelvic fins and modal fin ray counts of D-VII,10 A-9 and Pect-16-17
indicate Barbulifer spp. Other seven-spined
gobies with this modal fin ray count have divided pelvic fins and include Pycnomma
roosevelti, Psilotris
spp., and Chriolepis
spp. The remaining candidate goby is Gobiosoma
grosvenori which shares the fin ray counts, but is said to have a partially-divided
pelvic fin (since the rest of the genus Gobiosoma
spp. have typical fused pelvic fins, the pelvic fin in larval G.
grosvenori may not be divided and then could match this type). This larval
type, however, has the shape characteristic of Barbulifer
spp., i.e. a large broad and flattened head, a wide mouth, a short pelvic
fin with a frenum, and a wide caudal peduncle. There are two Caribbean species
with the same fin ray counts: B. ceuthoecus
and B. antennatus. The latter is reported
only from the Bahamas through the Antilles, but the larvae are likely to be similar
or identical. The remaining seven-spined gobies all have a mode of more than 10
second dorsal fin elements. The very different-appearing Pycnomma
roosevelti larval type shares the fin ray counts and the possibility of
it representing some other form of Barbulifer spp.
cannot be completely excluded. (PE) G18 | |
| | Analogues:
| | |
| Description:
Body thick, long, and somewhat narrow with a small eye and a terminal large
wide mouth. Head broad and slightly flattened. Pectoral fins relatively long,
reaching much of the way to the vent. Pelvic fins short, extending less than halfway
to the vent and fused with a small frenum (some larvae show split pevic fins that
are artifacts). Dorsal and anal fin bases short, caudal peduncle relatively wide
and long and procurrent caudal fin rays 8-10 (8-9 spindly). Lightly marked, mostly
along the ventral midline: at the isthmus, just forward of the pelvic fin insertion,
then sometimes on the abdomen just behind the pelvic fin insertion, then three
or four melanophores spaced along the anal fin base (often paired, one per side)
and then a row (or streak) of three or four extending along the caudal peduncle
ending near the start of the procurrent caudal fin rays. The abdominal melanophores
are quite variable, missing in some individuals and a clear Y-shape diverging
from the pelvic fin insertion in others (post-pelvic Y). Melanophores are present
on the base of most of the lower caudal fin segmented rays extending up to halfway
along the rays. Melanophores on the head are limited to at the angle of the jaw
and sometimes on the inner (mouth) side of the lower jaw. Characteristically,
there is a large melanophore or two overlying the cleithrum just behind the operculum
and just forward of the pectoral fin base. This melanophore can be absent on very
lightly-marked individuals. There are internal melanophores around the sacculus,
on the dorsal surface of the swim bladder, and around the gut near the vent. Series
of transitional larvae show that the eye develops from a slightly narrowed vertical
oval, sometimes tilted forward, to larger and round. Transitional larvae always
have the melanophore overlying the cleithrum just forward of the base of the pectoral
fin, and often more around the base of the pectoral fin. Melanophores then develop
as a scattering in a vague stripe on the body underlying the pectoral fin rearwards.
In addition, there can be melanophores on the inside of the mouth at the tip of
the lower jaw and a few tiny ones around the maxilla. | |
|
|
| Barbulifer ceuthoecus
larva | | 9.0 mm SL | | San
Blas, Panama, SB83-169 | |  |
| Barbulifer ceuthoecus
larva | | 9.3 mm SL |
| slightly narrowed eye | | San
Blas, Panama, SB87-218 | |  | | |  | | |
|
| Barbulifer ceuthoecus
larva | | 9.9 mm SL | | lightly
marked | | San Blas, Panama, SB80-105 |
|  |
| Barbulifer ceuthoecus
larva | | 9.5 mm SL | | broad
head and inner mouth melanophores | | San Blas,
Panama, SB87-228 | |
 | | |  |
| Barbulifer ceuthoecus
transitional larva | | 9.4 mm SL |
| San Blas, Panama, SB86-331 | |  | | |  | | |  |
| |  |
| | | |
|
Goby 1125 vs.
Barbulifer ceuthoecus (early) |
| |
| | Diagnosis:
A larval type with D-?,10 A-9. Unfortunately, the 10/9 fin ray count is
the most common formula for Caribbean gobies and there are many candidates for
this larval type. The basic melanophore pattern, i.e. a melanophore at the angle
of the jaw, a row along the anal fin base continuing to the start of the lower
procurrent caudal fin rays and melanophores at the base of most of the lower segmented
caudal fin rays, is shared with larval Barbulifer
ceuthoecus and the six-spined Coryphopterus
spp. In most features, this larval type fits with what would be expected
for immature B. ceuthoecus
larvae, i.e. the pattern of melanophores (especially the post-pelvic Y), the small
round eye, the flattened head shape with a very broad mouth, and the relatively
wide caudal peduncle. However, the melanophore just forward of the vent on the
abdominal promontory is not found on other B.
ceuthoecus larvae, and this larval type is therefore described separately
(pending intermediate individuals or DNA sequencing). Amongst the Coryphopterus
spp., only C. alloides has as few
as 9 anal fin elements. Arguing against C. alloides
is the small eye and flattened head shape. Interestingly, the melanophore on the
abdominal promontory does occur on some rare specimens
of presumptive Coryphopterus
glaucofraenum (with 10/10, 18 pectoral fin rays and a large eye, but species
id not certain). Among the remaining 10/9 gobies, some have identified larval
types (Bathygobius
spp., Lythrypnus
spp., Priolepis
spp.), some are members of genera that have larvae that are quite different
in appearance (Gobiosoma
spp. (i.e. G. grosvenori) and Psilotris
spp.), and others have features inconsistent with this larval type (a
large eye in Chriolepis
spp.). The species that cannot be excluded comprise Coryphopterus
alloides, Lophogobius cyprinoides,
and Pycnomma roosevelti.
A larval type tentatively assigned to P.
roosevelti slightly resembles this larval type in form, but has a different
melanophore pattern. | |
| Analogues:
(light markings with anal fin-caudal peduncle row + jaw angle, small: < 8 mm
SL) Within the diverse light and anal fin-caudal peduncle row group, there
are many very-similar larval types. Two of the most common larval genera share
this basic marking pattern including the melanophore at the angle of the jaw:
Lythrypnus spp.
(without the caudal fin melanophores) and Coryphopterus
glaucofraenum and C.
dicrus+. A few Elacatinus
spp. are the only seven-spined gobies to share the anal fin-caudal peduncle
row of melanophores, but, as a rule, they do not have the melanophore at the angle
of the jaw. All three of the aforementioned groups are typically wider-bodied
and do not have the flattened head appearance and very broad mouth. Furthermore,
their eyes are either narrowed vertical ovals or large and round, without the
smaller slightly flattened eye exhibited by this larval type. They do not share
the post-pelvic Y marking and only a rare Coryphopterus
sp. specimen exhibits an abdominal promontory melanophore. Typical Barbulifer
ceuthoecus larvae are larger, usually more than 9 mm SL, and thicker (but
may represent the mature version of this larval type). The larval eleotrid Dormitator
maculatus has a similar general appearance and shares most of the markings,
including the abdominal promontory and jaw angle melanophores, but the abdominal
midline streak extends to the level of the swimbladder (shared with the other
eleotrid species) and there is no internal melanophore around the gut near the
vent. Some immature larvae of the long gobies, such as
Microgobius spp. superficially resemble this type, but have many more
median fin rays and very short caudal peduncles and are usually longer than 8
mm SL. Immature Bollmannia
boqueronensis larvae may resemble this type, but have more median fin
rays and a much larger irregular eye, along with additional melanophores. |
| | Description:
Body relatively thick, long, and narrow with a medium round eye and a terminal
large wide mouth. Head broad and slightly flattened. Dorsal and anal fin bases
short, caudal peduncle relatively wide and long and procurrent caudal fin rays
8-9 (8 spindly). Lightly marked, mostly along the ventral midline: at the isthmus,
along the pelvic fin insertion and extending onto the abdominal midline, often
with a clear Y-shape diverging from the pelvic fin insertion (post-pelvic Y),
then often a melanophore on the abdominal promontory just forward of the vent,
followed by paired melanophores along the anal fin base and then a row (or streak)
extending along the caudal peduncle ending near the start of the procurrent caudal
fin rays. Melanophores are present on the base of most of the lower caudal fin
segmented rays. Melanophores on the head are limited to the angle of the jaw.
There are internal melanophores along the dorsal surface of the swim bladder and
around the gut near the vent. | | |
|
| Goby 1125 larva |
| 7.4 mm SL | | San
Blas, Panama, SB86-1125 | |  |
| |  |
| Goby 1125 larvae |
| 7.1, 7.4, and 8.0 mm SL | larva
at bottom shown ventral aspect up
with a post-pelvic Y and an abdominal
promontory
melanophore | | San Blas, Panama, SB86-1125 |
|  |
Dormitator
maculatus larva above
vs. Goby 1125 larva below | note
abdominal midline melanophores,
long streak vs. Y | | San
Blas, Panama, SB86-1123 | |
| | | |
| |
|
| | Diagnosis:
Modal fin ray counts of D-VII,12 (11) A-10 (9) and Pect-16-17 along
with fused pelvic fins indicate Risor ruber
and Ginsburgellus novemlineatus. These genera
typically have two fewer anal fin rays than second dorsal fin rays. Elacatinus
gemmatus usually has one fewer anal fin ray and also has slightly fewer
pectoral fin rays (15-16). This larval type represents R.
ruber since it has unusual enlarged spiny scales along the ventral caudal
peduncle. The identification would be difficult if these characteristic scales
were absent because larval R. ruber are otherwise similar to the larvae
of the large group of Gobiosoma
spp. and Elacatinus spp.
gobies discussed below. The enlarged scales are an apparent adaptation to sponge-dwelling
and can be seen on the larvae of the other sponge gobies, Evermannichthys
spp. The latter genus can overlap the median fin ray count for R. ruber,
however they have many fewer pectoral fin rays, usually only 12 or 13. Ginsburgellus
novemlineatus has no spiny scales and a tiny pelvic fin cup compared to
R. ruber, which has long fused pelvic fins
reaching to the vent. Other gobies that can share the modal twelve second dorsal
fin elements and ten anal fin elements have differing modal pectoral fin ray counts
and, of course, no enlarged spiny scales: Elacatinus
gemmatus (Pect-15-16), Gobiosoma spilotum
(Pect-18-19), Elacatinus chancei (Pect-18-20),
and Gobiosoma hemigymnum (Pect-20-21). At
transition, R. ruber becomes very distinct morphologically, with a sharply-blunted
snout and uniquely curved and protruding fangs. (U) | |
| Analogues:
(anterior anal fin base and caudal peduncle spot only) This larval type
has only one melanophore at the anterior portion of the anal fin base (thus far),
while larval Elacatinus pallens
have two or more. Larval Evermannichthys
spp. can also have the enlarged spiny scales on the ventral caudal peduncle,
but the spines are pigmented, there are no anal fin base melanophores, and the
head is pointed and the body more elongate. | |
| Description:
Body thin, long, and narrow with a large eye and a terminal small mouth.
Pectoral and pelvic fin lengths unknown. Dorsal fin base long, anal fin base medium-length
and caudal peduncle medium-length and width, 4-6 procurrent caudal fin rays (4-5
spindly). Very lightly marked: melanophores absent from the head, thoracic, and
pelvic region and present only as a single melanophore on the body below the base
of the third and fourth anal fin elements and two adjacent melanophores on the
ventral midline of the caudal peduncle just after the last anal fin ray. Internal
melanophores occur only along the dorsal surface of the swim bladder. There are
several prominent spiny scales along the ventral midline of the caudal peduncle
extending up to the start of the lower procurrent caudal fin rays. There are no
melanophores on the scales. The eye is round with slight dorsal and ventral indentations
in the iris and a small extension of the iris in the posterior-inferior direction.
there is a speckled membrane over the upper eyeball separate from the pigmented
iris below. Recruits: Body somewhat thin, long, and narrow with a large eye and
a very blunt snout with a small subterminal mouth and protruding curved fangs.
Pectoral fins long, reaching to vent, pelvic fins long and fused with a frenum
and extending to the vent. Dorsal and anal fin bases medium length, caudal peduncle
long and wide for a goby. A row of large spiny ctenoid scales are present along
the ventral midline of the caudal peduncle as well as partly over the rear body.
The head and body are uniformly densely spotted with discrete large melanophores
and the median fins are darkened. | | |
|
| Risor ruber larva |
| 4.7 mm SL | note
ventral caudal peduncle spiny scales
D-VII,12 A-10 Pect-16 | | San
Blas, Panama, SB87-201 | |  |
| |  | | |  | | |  |
| Risor ruber recruit |
| 8.8 mm SL | | Barbados,
Henri Valles V05R23 | |  | | |
| | |
| | | |
| |
Notes on Elacatinus spp.
and Gobiosoma
spp. | | |
| | This
large group of small seven-spined gobies separates out into three basic groups:
the conspicuously-striped Elacatinus spp. cleaner gobies, the non-cleaner
Elacatinus spp., and the Gobiosoma spp. Identification of larvae
to species in this large group is obviously difficult and DNA sequence identification
is often necessary. Since many of these gobies have restricted ranges within the
region, knowledge of the geographic location can reduce the number of possible
candidates and can be instrumental in identifications. The larvae of these seven-spined
goby larvae are similar in general appearance to those of some six-spined species,
especially Lythrypnus
spp. and Coryphopterus
spp., but with the characters presented here they should be easily separated. |
| |
Larval identifications can be problematic since the fin ray counts of many of
these species overlap (although modal counts can be helpful). Easiest to separate
are the cleaner gobies who have higher modal medial fin ray counts, usually D-VII,12
A-11. The remaining non-cleaner Elacatinus spp. typically share medial
fin ray counts with the Gobiosoma spp., making this large group of gobies
particularly hard to identify. Fortunately, pectoral fin ray counts vary between
species and many of these species have restricted geographic ranges. |
| | History:
These gobies have a complex taxonomic history and have been shuffled around a
number of genera: the present non-cleaner Elacatinus spp. are the former
Tigrigobius spp. The present Gobiosoma spp. group includes the former
Garmannia spp. and Austrogobius spp. The cleaner gobies, presently
considered Elacatinus spp., have been included in Gobiosoma spp.
and are often listed as such in the literature. | |
| Elacatinus spp. |
| | Cleaner
subgroup: The Elacatinus spp. cleaner
gobies have higher modal fin ray counts than the non-cleaners, D-VII,12 A-11
(except E. chancei with 10 anal fin elements and E. oceanops with
a mode of 12 anal fin elements). As larvae they do not have a conspicuous cup-shape
to the pelvic fin and the pelvic fin frenum is not immediately obvious. Geographic location
is very important to identification of these gobies. | | |
| Non-cleaner
subgroup: Lower modal fin ray counts of D-VII,11 A-10 and Pect-15-21
are characteristic of the Elacatinus spp. non-cleaner subgroup (the former Tigrigobius
spp.). The fin ray counts are shared by many of the present Gobiosoma
spp. (discussed separately below). These two groups are not especially different in appearance.
| |
| The
Elacatinus spp. non-cleaner subgroup separates out by modal pectoral fin
ray counts: E. gemmatus with 15, E.
saucrus and E. pallens
with 16, E. dilepis and E. macrodon with 17, E. zebrellus
with 18, and E. multifasciatus
with 20-21 pectoral fin rays. | |
| Elacatinus
spp. exceptions to the standard D-VII,11 A-10 fin ray count are E.
pallens with a modal fin ray count of D-11 A-9 and most E. gemmatus
and many E. multifasciatus
with D-12 A-10 (formerly Tigrigobius gemmatum and T. multifasciatum).
| | |
| Gobiosoma spp. |
| | | The
present genus Gobiosoma spp. includes a number of tiny non-descript species,
several limited to US waters (G. bosci, G. ginsburgi, G. longipala, and
G. robustum). Most Caribbean species have a modal fin ray count of D-VII,11
or 12 A-10. | | |
| Those
Caribbean species with a mode of eleven second dorsal fin elements include G.
spes with a mode of 15-16 pectoral fin rays, G. hildebrandi (recorded
at both the Pacific and Atlantic mouths of the Panama Canal) with a mode of 17
pectoral fin rays, G. schultzi (from Lake Maracaibo, Venezuela) with a
mode of 17-18 pectoral fin rays. Note: these fin ray counts can be shared with
several non-cleaner Elacatinus spp. discussed above. | |
| Those
with a mode of twelve second dorsal fin elements include G. spilotum (Pect-18-19)
and G. hemigymnum (Pect-20-21). This median fin ray count is shared with
some other gobies: Ginsburgellus novemlineatus (Pect-17 and a tiny pelvic
fin cup), Risor ruber (D-11-12,
A-9-10, Pect-16-17 and uniform dark pigmentation), Elacatinus gemmatus
(Pect-15-16), and one cleaner goby: E. chancei (D-11-12, A-10, Pect-19-20).
This subset of species usually has two fewer anal fin rays than dorsal fin rays
(the others with two fewer are G. yucatanum, E.
pallens, and many E.
multifasciatus). Note that for the Caribbean (including South Florida
but outside the Gulf of Mexico) the combination of 12 second dorsal fin elements
and 11 anal fin elements is limited to the cleaner
gobies (except for rare individuals of other groups). Some of the temperate
US and Gulf of Mexico Gobiosoma spp.
share these fin ray counts. | |
| | Caribbean
Gobiosoma spp. exceptions to the standard D-VII,11 or 12 A-10 fin ray counts
are G. grosvenori with modally one fewer dorsal and anal fin ray, D-10
A-9 (shared among the seven-spined, fused-pelvic fin gobies by the two Barbulifer
spp. (all three with modal 17 pectoral fin rays) and G. yucatanum
with modally one fewer anal fin ray, D-11 A-9 Pect-15-16 (shared with E.
pallens). | | |
| The US and
Gulf of Mexico Gobiosoma spp. can have higher median fin ray counts D-VII,12
or 13 A-11 Pect. 17-19 in G. bosc
and G. ginsbergi (shared by many cleaner gobies) or the same as most other
regional species (D-VII,11 or 12 A-10 Pect. 15-17) in G. longipala and
G. robustum. | | |
| Elacatinus/Gobiosoma spp. vs. the six-spined
gobies | |
| Many Elacatinus/Gobiosoma
spp. larvae superficially resemble those of Lythrypnus
spp. and Coryphopterus
spp. (both six-spined). Since the latter are very common larvae and the
number of dorsal fin spines is not always easily apparent, the two groups can
be easily confused. There are, however, several basic features that should quickly
serve to separate the groups (other than counting dorsal fin spines): |
|
| the
row of melanophores along the ventral midline of the caudal peduncle extends close
to, or up to, the start of the procurrent caudal fin rays in Coryphopterus
spp. and, with uncommon exceptions, in Lythrypnus
spp. In Elacatinus/Gobiosoma spp. larvae, the row, if present,
stops well before the start of the procurrent caudal fin rays. |
| | | The
melanophore at the angle of the jaw is present in all Lythrypnus
spp. larvae and many Coryphopterus
spp. larvae (i.e. the vast majority of C.
glaucofraenum and C.
dicrus, but not in C.
personatus/hyalinus). It is absent in all Elacatinus/Gobiosoma spp.
larvae identified thus far. | |
| | Coryphopterus
spp. larvae have more procurrent caudal fin rays, usually 8 or 9, than
do Elacatinus/Gobiosoma spp. larvae (or Lythrypnus
spp.), who usually have only 5 or 6. | |
| | | Of
course, this discussion is limited to the larval taxa so far identified. Photographs
below of the tail end of larval C.
glaucofraenum above and Elacatinus
multifasciatus below. | |
|  |
|  |
| | Elacatinus/Gobiosoma
spp. vs. other seven-spined gobies | |
| Risor
ruber and Ginsburgellus novemlineatus share fin ray counts with
the Elacatinus/Gobiosoma spp. and are discussed with them below. Larval
Gobulus myersi
have similar markings and fin ray counts (D-VII,11-12 A-10-11), but have partially-divided
pelvic fins and a different body shape: the dorsal and anal fins are placed further
back on the body and the pectoral and pelvic fins are shorter than those of larval
Elacatinus/Gobiosoma spp. and they have no pelvic frenum (top photograph,
below). Furthermore, as the larvae approach transition they develop a flattened
head and broad mouth, a shape not found in larval Elacatinus/Gobiosoma spp.
For comparison, the lower photograph is of a larval Gobiosoma (spes
?), the larval type most likely to be confused, i.e. with the shortest pelvic
fins in the group and without an obvious pelvic cup. | |
 |
|  |
| |
|
Note: Gobiosoma/Elacatinus
spp.+ group presented in order of increasing anal fin elements
(non-cleaner
Elacatinus first) | | |
| |
|
| | Diagnosis:
Modal fin ray counts of D-VII,11 A-9 and Pect-16 indicate Elacatinus pallens
and Gobiosoma yucatanum and overlaps the lower
range of Risor ruber (some
Psilotris spp.
share the fin ray count but have divided pelvic fins and a different gestalt).
These taxa typically have two fewer anal fin rays than second dorsal fin rays.
E. pallens (Pect-16, occasionally
15) fits the modal fin ray count while G. yucatanum
(Pect-16 with range 15-18) is ostensibly only found along the Yucatan peninsula
and should have a well-developed pelvic frenum. Some individuals of this E.
pallens larval type have counts that range down to D-VII,10 A-8
Pect-15. Larvae with D-VII,10 A-9 Pect-16-18 could represent Gobiosoma
grosvenori (which have mostly divided pelvic fins in adulthood), but G.
grosvenori does not fit this larval type since it should not have 15 pectoral
fin rays and should develop a stripe extending straight back from the eye, a feature
not shown in transitional larvae of the type described here. A small fraction
of E. saucrus and E.
dilepis larvae do have 9 anal fin rays, but have different markings and
an obvious pelvic cup and a more appropriate larval type is identified. Risor
ruber usually has more fin rays, with a mode of D-VII,12 A-10 Pect-17
(some individuals may rarely overlap the fin ray counts of this larval type).
There are more appropriate larval types identified for Psilotris
spp. (PE) G7ab | |
| Analogues:
(anterior anal fin base and caudal peduncle spot only) This larval type
has two or more melanophores at the anterior portion of the anal fin base, while
larval Risor ruber appear to
have only one (thus far). | |
| Description:
Body relatively thin, long and narrow with a large eye and a medium-sized
low terminal mouth. Pectoral fins long, reaching past the vent. Pelvic fins long,
reaching about two-thirds of the way to the vent without an obvious frenum or
cup. Dorsal and anal fin bases medium length, caudal peduncle long and narrow
and only 4-6 procurrent caudal fin rays (4-5 spindly). Very lightly marked along
the ventral midline: melanophores absent from thoracic and pelvic region and present
as a short row of two to four along anal fin base between the third and seventh
element (variably paired and variably one per side) and then one large melanophore
just after the last anal fin ray. Some individuals have a surface melanophore
just forward of the anal fin origin. Internal melanophores at the dorsal surface
of the swim bladder. Series of transitional larvae show the eye remains round.
Transitional larvae first develop two arcs of melanophores across the top of the
head between the eyes, subsequently two more arcs develop behind the eyes and
then two bars of melanophores develop below the eye (corresponding iris melanophores
at about 12, 2, 5, and 7 o'clock). A scattering of tiny melanophores develops
along the upper jaw and around the nasal bones. | |
|
|
| Elacatinus pallens
larva | | 6.1 mm SL | | early
transitional body shape? | | San Blas, Panama,
SB84-624a | |  |
| |  |
| Elacatinus pallens
early transitional larva | | 6.7 mm SL |
| San Blas, Panama, SB86-426 | |  | | |  |
| |
 |
| Elacatinus pallens
transitional larva | | 7.0 mm SL |
| D-VII,10 A-8 Pect-16 | | San
Blas, Panama, SB86-228 | |
 |
| |  | | |  | | |  | | |  | | |  | | |  |
| Elacatinus pallens
transitional larva | | 6.0 mm SL |
| D-VII,10 A-8 Pect-15 | | San
Blas, Panama, SB86-625 | |  | | |  |
| |  |
| | |
| |
|
| | Diagnosis:
Fused pelvic fins with a prominent pelvic cup and a modal fin ray count of D-VII,11
A-10 and Pect-16 indicate Elacatinus saucrus
or Gobiosoma spes. These taxa
typically have one fewer anal fin ray than second dorsal fin rays. G.
spes fits the modal fin ray counts but has a large proportion of individuals
with 12 second dorsal fin elements and/or 9 anal fin elements which this larval
type has only rarely (other species with the low pectoral fin ray count comprise
E. gemmatus has a mode of 12 second dorsal
fin elements and Gobiosoma yucatanum has a
mode of 9 anal fin elements). Elacatinus dilepis
shares most features with E. saucrus, but has a mode of 17 (or 18) pectoral
fin rays, and therefore individuals cannot be excluded from this larval type (this
larval type has 15-17 pectoral fin rays with a strong mode at 16). Transitional
recruit with a prominent row of black spots along the side of the body below the
lateral midline confirms E. saucrus (absent in transitional recruits of
E. dilepis). Other less-likely candidates,
all of which have a mode of 17 or more pectoral fin rays, include E.
macrodon (Florida to Haiti), Gobiosoma schultzi
(Lake Maracaibo, Venezuela), G. hildebrandi
(Panama only), and Elacatinus zebrellus (formerly
Tigrigobius zebrella, which has a mode of
18 pectoral fin rays). (U) G7 | |
| Analogues:
| |
| Description:
Body relatively thin, long, and narrow with a medium eye and a terminal,
medium-sized mouth and often thick lips. Pectoral fins long, reaching to vent,
pelvic fins long and form a large obvious cup extending about two-thirds of the
way to the vent. Dorsal and anal fins relatively short, caudal peduncle long and
narrow, procurrent caudal fin rays 6-8 (6-7 spindly). Lightly marked along the
lower body: melanophores along the ventral midline at the isthmus (sometimes missing)
and the pelvic fin insertion, along the anal fin base (paired, one per side) and
extending along the ventral peduncle ending well before the start of the procurrent
caudal fin rays. Internal melanophores at the dorsal surface of the swim bladder
and sometimes around the gut near the vent. Melanophores sometimes present on
the base of several of the lower caudal fin segmented rays and extending out a
short distance along the rays. Series of transitional larvae show the eye remains
round. Transitional larvae develop a blunt snout profile and develop bars radiating
from the eye and bands across the top of the head, connected by a large X pattern
over the brain. Patches of melanophores develop on the preopercle, on the base
of the pectoral fin, and in a prominent row along the dorsal midline of the body
as well as along the lateral midline and around the base of the caudal fin rays.
| | |
|
| Elacatinus saucrus
larva | | 7.8 mm SL | | San
Blas, Panama, SB83-161 | |  |
| |  |
| Elacatinus dilepis ?
larva | | 8.3 mm SL | high
fin ray counts D-VII,12 A-11 Pect-17
but markings of this larval type |
| San Blas, Panama, SB86-808 | |  | | |
|
| Elacatinus saucrus +
larva | | 7.7 mm SL | | 17
pectoral fin rays | | San Blas, Panama, SB86-414 |
|  |
| |
 |
| Elacatinus saucrus +
transitional larva | | 7.6 mm SL |
| Pect-17 | | San
Blas, Panama, SB86-502 | |  | | |  |
| Elacatinus saucrus
transitional larva | | 7.9 mm SL |
| Pect-15 | | San
Blas, Panama, SB86-809 | |  |
| Elacatinus saucrus
transitional larva | | 7.9 mm SL |
| Pect-16 | | San
Blas, Panama, SB87-121 | |  |
| Elacatinus saucrus
late transitional larva | | 7.7 mm SL |
| San Blas, Panama, SB86-1224 | |  | | |  |
| |  |
| | |
| |
| Elacatinus multifasciatus | | |
| | Diagnosis:
Modal fin ray counts of D-VII,11-12 A-10 and the high pectoral fin ray count of
20-21 indicates Elacatinus multifasciatus.
This larval type has a short pelvic fin extending about half way to the vent with
a well-developed frenum. Gobiosoma hemigymnum shares the high pectoral
fin ray count, but has 12-13 second dorsal fin elements and occurs in the West
Indies and Brazil (not recorded in Panama). Individual Gobiosoma
spilotum cannot be excluded (a mode of 19 pectoral fin rays with an occasional
20). Gobiosoma nudum, a Pacific species reported in the Caribbean near
the mouth of the Panama Canal, sometimes has 20 pectoral fin rays (18-20), but
should have 12-13 second dorsal fin elements, not often eleven as in this larval
type. (PE) G405 | |
| Analogues:
| |
| Description:
Body thin, long and somewhat narrow with a large eye and a terminal mouth.
Pectoral fins fins long, pelvic fins medium length and form an obvious short cup
(a protruding frenum) extending about halfway to the vent. Dorsal and anal fin
bases relatively short, caudal peduncle long and narrow. Lightly marked along
the lower body: melanophores along the ventral midline at the pelvic fin insertion
(rarely also at the isthmus), along the anal fin base (paired, one per side) and
extending along the ventral peduncle ending well before the start of the procurrent
caudal fin rays. Internal melanophores at the dorsal surface of the swim bladder
(not around the gut near the vent?). | | |
|
| Elacatinus multifasciatus
larva | | 6.9 mm SL | | Pect-20 |
| San Blas, Panama, SB86-625 | |  |
| |  |
| Elacatinus multifasciatus
larva | | 7.6 mm SL | | Pect-21 |
| San Blas, Panama, SB86-516 | |  |
| Elacatinus multifasciatus
larva | | 7.0 mm SL | | Pect-21 |
| San Blas, Panama, SB86-405 | |
 |
| |
 |
| |
 |
| |  |
| Elacatinus multifasciatus
larva | | 7.3 mm SL | D-VII,11
A-10 P-20
this count overlaps several species | | San
Blas, Panama, SB86-502 | |  |
| | |
| |
|
| | Diagnosis:
Larvae with fused pelvic fins and a fin ray count of D-VII,11-12 A-10
and Pect. 15-17 can occur in several species including a group of Gobiosoma
spp. (G. hildebrandi, G.
schultzi, G. spes, and G.
yucatanum), several Elacatinus spp. (E.
pallens, E. saucrus,
E. dilepis and E. gemmatus)
and occupy the lower end of the range for the cleaner
gobies of Elacatinus spp.). This larval type has a relatively short
fused pelvic fin without an obvious pelvic frenum. The Elacatinus
spp. are unlikely candidates and/or have other types assigned as follows:
E. pallens should have no
more than 9 anal fin elements and the larval type matching it has a longer pelvic
fin, E. saucrus (and E.
dilepis) have a prominent pelvic frenum and a more appropriate common
larval type is identified, and E. gemmatus
rarely has fewer than 12 second dorsal fin elements (but cannot be excluded).
Gobiosoma spes is left by elimination: G.
schultzi is from Venezuela, G. yucatanum
is from the Yucatan only, and G. hildebrandi
is a Pacific species that has invaded the Panama Canal (but cannot be ruled out
in Panama). However, G. spes is supposed to
have a well-developed frenum, not apparent on this larval type. Nota
bene: These larvae are quite similar to the Elacatinus
illecebrosus type (below), but have the lower fin ray counts (and shorter
pelvic fins, only about half-way to the vent). The transitional larva of this
type has a wider scattering of melanophores on the top of the head along with
some additional melanophores around the jaw and below the eye not seen (so far?)
in several transitional cleaner gobies. Nonetheless, given the wider ranges for
fin ray counts than reported in the literature for many species, the possibility
that these larvae represent variant cleaner gobies cannot be excluded. (PE) G419
| |
| Analogues:
| |
| Description:
Body relatively thin, long, and narrow with a small to medium eye and a
terminal, somewhat small mouth. Pectoral fins long, reaching to or past vent.
Pelvic fins medium length and do not form an obvious cup and do not have an obvious
frenum, extending about halfway (or less) to the vent. Dorsal and anal fin bases
medium length and caudal peduncle medium length and width. A single melanophore
on the caudal peduncle ventral midline just after the last anal fin and internal
melanophores only at the dorsal surface of the swim bladder and sometimes around
the gut near the vent. Transitional larvae develop a sparse scattering of small
melanophores on upper part of the head with some melanophores developing around
the jaws (perhaps an incipient stripe from the eye across the mid-jaw) and below
the eye. | | |
|
| Elacatinus/Gobiosoma sp.
A larva | | 6.8 mm SL |
| D-VII,12 A-10 Pect-16 | | San
Blas, Panama, SB86-810 | |  |
| Elacatinus/Gobiosoma sp.
A larva | | 5.8 mm SL |
| D-VII,11 A-10 | | San
Blas, Panama, SB86-419 | |  | | |  | | |
 |
| |
 |
Elacatinus/Gobiosoma
sp. A
transitional larva | | 6.5
mm SL | D-VII,11 A-10 Pect-17, sparse head
melanophores,
and with jaw melanophores | | San Blas, Panama,
SB86-710 | |
 |
| |  |
| | |
| |
Notes on the cleaner gobies of
Elacatinus
spp. | |
|
| | Modal
fin ray counts of D-VII,12 A-11 and Pect-16-19 and fused pelvic fins indicate
some of the cleaner gobies of the genus Elacatinus (formerly considered
Gobiosoma spp.). This genus typically has one fewer anal fin ray than second
dorsal fin rays. Among cleaner gobies there are few exceptions to this modal median
fin ray count: E. oceanops may often have
D-VII,13 and/or A-12 and E. chancei has a
modal count of A-10. Pectoral fin ray counts can broadly overlap. Only a rare
individual of Risor ruber,
Elacatinus gemmatus, E. saucrus,
E. dilepis, or Gobiosoma
spes should share the combination of 12 second dorsal fin elements and
11 anal fin elements. | |
| It is likely that larval cleaner
gobies have a similar appearance and the identification would depend on location,
and, if necessary, DNA sequencing. Unlike most other Caribbean reef fishes, cleaner
gobies have restricted ranges to varying degrees and thus location is important
for larval identifications. In addition, habitat is an important distinction,
with one set of species skating around on live coral heads and usually abundant
in shallow water and another set living in and around sponges, and often in deeper
water. The former group are far more common and conspicuous on reefs and comprise
E. atronasus (not E. atronasum), E.
evelynae, E. genie, E.
illecebrosus (not E. illecebrosum), E. prochilos, E. oceanops,
and E. randalli. The latter
group are more obscure and comprise E. chancei, E.
horsti, E. lori, E. louisae, E. tenox, and E. xanthiprora. |
| | Much
of the literature disagrees on techniques for distinguishing similar-appearing
species: some depend on the fine points of the relative width of stripes, which
seems to me to be variable, especially on juveniles. There is also some disagreement
on the description of the snout: clearly some species have the classic "sharknose"
appearance with a protruding snout and sub-terminal upper lip, but some species
have a terminal upper lip with an underslung lower jaw (see the juvenile E.
illecebrosus below). Unfortunately the "sharknose" appellation has been
applied to both morphologies. Furthermore, it is clear that larval cleaner gobies
do not have the underslung jaw and juveniles may not show the protruding snout
until they approach adulthood. | | |
| |
|
|
| | Diagnosis:
Modal fin ray counts of D-VII,12 A-11 and Pect-16 and fused pelvic fins
indicate some of the cleaner gobies of the genus Elacatinus
(formerly considered Gobiosoma spp.). This genus typically has one fewer
anal fin ray than second dorsal fin rays. This larval type has a mode of 16 and
a range of 15 to 18 pectoral fin rays (according to Bohlke and Robins, only the
Bahamian endemic E. atronasus has a mode of
16 pectoral fin rays, but E. evelynae
is split evenly between 16 and 17 pectoral fin rays and E.
illecebrosus, E. oceanops and E. genie have a significant portion
of individuals with 16 pectoral fin rays). According to Pat Colin (pers.comm.),
the common shallow-water cleaner goby in Panama is E.
illecebrosus. This bar-nosed species occurs in the western and southern
Caribbean. (U) G7S | |
| Analogues:
Larvae of the cleaner gobies are likely identical, but recruits and juveniles
of E. illecebrosus are separated from the
other bar-nosed species (E. illecebrosus, E. randalli,
and E. xanthiprora) by having a mostly dark area in front of the eyes below
the bar (vs. E. randalli)
and a terminal upper lip (vs. E. xanthiprora,
a deeper reef species usually found in and around sponges). The latter distinction,
however, is uncertain, since the degree of "sharknose" development between E.
illecebrosus and E. xanthiprora seems
to vary with ontogeny. Fortunately, E. xanthiprora
has more pectoral fin rays (18-20). | |
| Description:
Body relatively thin, long, and narrow with a small to medium eye and a
terminal, relatively small mouth. Pectoral fins long, reaching past the vent.
Pelvic fins medium length, extending less than about two-thirds of the way to
the vent, and have only a small frenum (and do not form an obvious cup). Dorsal
and anal fin bases medium length and caudal peduncle medium length and narrow
and 6-7 procurrent caudal fin rays. Typically only a melanophore on the caudal
peduncle ventral midline just after the last anal fin, but often no surface melanophores
at all. Internal melanophores only at the dorsal surface of the swim bladder (a
rare individual can have inconspicuous melanophores around the gut near the vent).
Series of transitional larvae show development of the eye from a slightly narrowed
vertical oval to round. Transitional larvae develop a loose scattering of small
melanophores on the top of the head and behind the upper eye (with no evidence
of a stripe at this stage). Transitional recruits develop two wide dark stripes
along the top of the head (separated by only a thin clear line) that merge to
become a stripe along the base of the dorsal fin fading out before the caudal
peduncle. The stripes on top of the head extend forward onto the snout encircling
a median white bar. Below the dark stripe is a prominent white stripe (yellow/blue
in life) starting on the upper aspect of the eyeball and extending back to the
tail. A wide lateral dark stripe starts at the tip of the upper jaw and continues
through the eye along the side of the body just below the lateral midline to the
caudal fin, widening at the caudal fin base and then extending out along the central
and lower fin rays. Beneath this surface stripe is a broad dark stripe of internal
melanophores that extends above and below the lateral midline. | |
|
|
| Elacatinus illecebrosus
larva | | 6.3 mm SL |
eye slightly narrowed;
D-VII,12 A-11 Pect-16 |
| San Blas, Panama, SB86-502 | |  |
| |  |
| Elacatinus illecebrosus
larva | | 6.5 mm SL |
| variant with no surface melanophores | | San
Blas, Panama, SB86-425 | |  | | |  |
| Elacatinus sp. cleaner
larva | | 7.2 mm SL | | D-VII,12
A-11 Pect-18 | | San Blas, Panama, SB86-502 |
|  |
| Elacatinus illecebrosus
larva | | 6.3 mm SL |
| note small frenum on fused pelvic fins |
| San Blas, Panama, SB86-425 | |
 |
| Elacatinus illecebrosus
early transitional larva | | 6.4 mm
SL | | D-VII,12 A-11 Pect-15 |
| San Blas, Panama, SB87-228 | |  | | |  | | |  | | |  | | |  |
| Elacatinus illecebrosus
transitional larva | | 6.2 mm SL |
| D-VII,12 A-11 Pect-16 | | San
Blas, Panama, SB86-709 | |  | | |  |
| Elacatinus illecebrosus
transitional larva | | 6.6 mm SL |
| D-VII,12 A-10 Pect-17 | | San
Blas, Panama, SB86-808 | |  | | |  |
| Elacatinus illecebrosus
transitional recruit | | 8.7 mm SL
| | San Blas, Panama, SB81-021 |
|  | | |  |
| Elacatinus illecebrosus
juvenile | | 17.5 mm SL |
| note underslung jaw but terminal upper lip |
| i.e. not true "sharknose" | | San
Blas, Panama, SB80-090 | |  |
| | |
| |
|
| | Diagnosis:
Modal fin ray counts of D-VII,12 A-11 and Pect-17 and fused pelvic fins
indicate some of the cleaner gobies of the genus Elacatinus (formerly considered
Gobiosoma spp.). This genus typically has one fewer anal fin ray than second
dorsal fin rays. Pectoral fin ray counts can broadly overlap, but this recruit
type has 17 pectoral fin rays. Fortunately there is only one species of cleaner
goby present in Noronha in Brazil, thus the identification is confirmed as Elacatinus
randalli. This bar-nosed species ranges from the Lesser Antilles down to
Brazil. (U) | |
| Analogues:
Larvae of the cleaner gobies are likely identical, but recruits and juveniles
of E. randalli are separated from the other bar-nosed species (E.
illecebrosus and E. xanthiprora) by having a mostly pale area in
front of the eyes below the bar. | |
| Description:
Transitional recruits develop two well-separated dark stripes along the top of
the head that merge to become a stripe along the base of the dorsal fin fading
out before the caudal peduncle. The snout has two thin extensions of the stripes
from the top of the head and a short bar along the midline. The remainder of the
snout and lips are unpigmented. A lateral dark stripe develops from the middle
of the eye to the caudal fin widening at the caudal fin base and then extending
out along the central and lower fin rays. Beneath this surface stripe is a broad
dark stripe of internal melanophores. A thin white (yellow in life) stripe then
develops between the lateral body stripe and the dorsal fin base stripe. |
| |
|
| Elacatinus randalli
transitional recruit | | 8.8 mm SL |
| Noronha, Brazil FN01 | |  | | |  |
| Elacatinus randalli
juvenile | | 27.0 mm SL | | Noronha,
Brazil FN01 | | 
| | | |
| |
|
| | Diagnosis:
Modal fin ray counts of D-VII,12 A-11 and Pect-16-17 and fused pelvic fins
indicate some of the cleaner gobies of the genus Elacatinus (formerly considered
Gobiosoma spp.). This genus typically has one fewer anal fin ray than second
dorsal fin rays. This V-nosed species is the common cleaner goby in Puerto Rico
and the Lesser Antilles. (U) | |
| Analogues:
Larvae of the cleaner gobies are likely identical, but recruits and juveniles
of E. evelynae are separated from the other V-nosed species (E. genie
and E. prochilos, both also "sharknosed") by a broad frenum connecting
the snout to the upper lip. E. genie, a very similar species from the Bahamas
and the Cayman Islands that shares the "sharknose" appearance is distinguished
by having the upper lip separated from the snout by a deep groove. E. prochilos
has the upper lip groove, a more Y-shaped mark on the snout, and is not supposed
to have the thin pale dorsal midline stripe from the dorsal fin forward (but whether
this applies to new recruits is uncertain). The morphological differences of the
mouth and snout may not be useful in the earliest recruit stages. |
| | Description:
Transitional recruits develop two wide dark stripes along the top of the
head (separated by only a thin clear line) that merge to become a stripe along
the base of the dorsal fin fading out between the two dorsal fins. Below the dark
stripe is a prominent white stripe (yellow/blue in life) that meets the stripe
from the other side in a distinct V-shape on the snout. A wide lateral dark stripe
starts at the tip of the upper jaw and continues through the eye along the side
of the body just below the lateral midline to the caudal fin, widening at the
caudal fin base and then extending out along the central and lower fin rays. Beneath
this surface stripe is a broad dark stripe of internal melanophores that extends
above and below the lateral midline. | | |
|
| Elacatinus evelynae
transitional recruits | | 9.1 and 8.6 mm SL
| | St. Thomas, USVI, ST506 | |  |
| Elacatinus evelynae
transitional recruits | | 9.0, 8.7 and 8.6
mm SL | | St. Thomas, USVI, ST506 |
|  |
| | | |
| | |
