|
| Group 1 Gobies | | |
| | |
| Although gobies are known for having fused
pelvic fins, often in the shape of a sucking disk, several goby genera have divided
pelvic fins to various degrees. The division can be partial or full, although
the bases of the split pelvic fins are usually in contact. This character is shared
by the related gobioids of the families Eleotridae
and Ptereleotridae, which
have pelvic fins that are separate, even at the base. | | | 
| | This
character has arisen independently many times in goby evolution and thus these
genera are not necessarily related. The state of the pelvic fins is useful in
larval identifications, although it is quite clear that this character can be
inconsistent in larval stages and can change at transition. The photograph at
right shows the divided pelvic fins in a larval Psilotris
amblyrhynchus. | | |
|
| In some gobies, the divided
pelvic fins are clearly acquired after the larval phase. For example, Coryphopterus
personatus larvae have fused pelvic fins despite the fact that juveniles
and adults have separated pelvic fins. A closeup photograph of the pelvic fin
of a 7.6 mm SL larval C.
personatus at right clearly shows the connecting membrane. Series of transforming
larvae show variable states of fusion of the pelvic fins. It should be noted,
however, that the majority of larvae in the collections have frayed fins and the
state of fusion cannot be evaluated. This is especially the case for the difficult
genus Coryphopterus
spp., where the pelvic fin morphology is, unfortunately, an important
species-level character. |  |
 |
 | Other
larval gobies, such as Gobulus myersi
and Psilotris amblyrhynchus,
can have partially-fused pelvic fins. G.
myersi is an interesting contrast to larval C.
personatus in that it shows the opposite sequence of pelvic fin morphological
changes: it starts as a partially-divided fin in larvae (left) and subsequently
fuses in adults. | | | |
| The only six-dorsal-spined
species with divided pelvic fins are a sub-group of Coryphopterus
spp. (C. alloides, C.
lipernes, C.
personatus, and C.
hyalinus). It is possible, if not likely, that the pelvic fins of all
of these species are not divided in pre-transitional larvae. | |
| | The seven-dorsal-spined
group with divided pelvic fins is quite heterogeneous (with some rare and obscure
deep-water taxa), comprising Psilotris
spp., Chriolepis spp.,
and Varicus spp. and the individual species
Pycnomma roosevelti and Robinsichthys
arrowsmithensis. | | |
| Three Caribbean goby species
have partially-divided pelvic fins (all seven-dorsal-spined): Gobulus
myersi, Psilotris amblyrhynchus,
and Gobiosoma
grosvenori. The latter is a member of the large genus Gobiosoma
with otherwise fused pelvic fins and thus it is unclear whether the larvae should
be expected to show any division in the pelvic fins. Gobulus
myersi adults have fused pelvic fins without a frenum, but larvae clearly
fitting this species have partially-divided pelvic fins (D-VII,11-12 A-10-11).
Two of the three other Gobulus spp. have partially-divided
pelvic fins as adults (all in the eastern Pacific), and thus the fused pelvic
fin in adult G. myersi may
be a derived character. In contrast, adult Psilotris
spp. have divided pelvic fins and the presence of partially-fused pelvic
fins in larvae of Psilotris amblyrhynchus
may indicate that divided pelvic fins are a derived character in that genus. |
| | |
Psilotris batrachodes has
the fewest fin rays (modal D-9 A-7); P.
alepis has D-10-11 A-8-9 and 15 pectoral fin rays and P.
celsus and P. boehlki both have D-10-11
A-9-11 (mode of 10) and 16-17 pectoral fin rays. P.
amblyrhynchus and P. kaufmani have
D-11-12 A-10-11 (mode of 11) and 18-19 pectoral fin rays (later in development
Psilotris spp. are scaleless). |
| | |
Pycnomma roosevelti has
a modal fin ray count of D-10 A-9 Pect-16 (and later develops scales). Gobiosoma
grosvenori also has modal D-10 A-9 but it has Pect-17 and has only partially-divided
pelvic fins and a small pelvic frenum and a very different body shape. |
| | |
The obscure deep-water taxa typically have divided and long pelvic fins and large
eyes. They comprise three species each of Chriolepis
spp. and Varicus spp. The former three
are Chriolepis benthonis (very deep-water,
Gulf of Mexico, D-10 A-9 Pect-16), Chriolepis
fisheri (known from deeper waters in Barbados and Bahamas only? D-11 A-10
Pect-16 from B&C, but I have the putative larvae from Panama), and Chriolepis
vespa (deep-water, Gulf of Mexico, D-11 (occ. 10) A-8 (7-9) Pect-15-17).
The latter three comprise Varicus bucca (very
deep-water, mode of D-9-10 A-8), V. marilynae
(deep-water, Florida only, D-9 A-8 Pect-16-18), and V.
imswe (deep-water, Belize, with pelvic fins extending beyond the anal fin
origin and D-8 A-8 Pect-15). A profoundly deep-water goby, Robinsichthys
arrowsmithensis, has D-VII,11 A-11 and is distinctive for 22-23 pectoral
fin rays. | | | |
Note: Fin ray counts for the second dorsal fin and the anal fin are total elements
(spines plus rays) and species are listed in rough order of increasing anal fin
rays. | | | |
| |
|
| | Diagnosis:
Clearly separated pelvic fins in the larval stage and modal fin ray counts of
D-VII,9 A-7 (occ. 8) and Pect-16 (usually two fewer anal fin rays than second
dorsal fin rays) indicate Psilotris batrachodes. This is the only Caribbean
goby with a modal count of as few as seven anal fin elements. (U) G19 |
| | Analogues:
(post-anal fin solitary melanophore, small: <7 mm SL) |
| | Description:
Body relatively thin, short and wide with a large eye and a terminal, somewhat
small mouth. Pectoral and pelvic fins short. Dorsal and anal fin bases relatively
long, caudal peduncle short and wide. By the time the fin ray complement has formed,
5.5 mm SL, melanophores are scattered over the body and in three patches along
the anal fin base. After that, melanophores develop in bars radiating from the
eye: forward across the jaw, a vertical below the eye and in bands across the
top of the head. A reticulated pattern of melanophores develops over the body.
Since the larvae were raised in captivity, the point of transition cannot be determined.
Series of larvae shows the eye remains round. | | |
|
| Psilotris batrachodes
larva | | 6.0 mm SL | | San
Blas, Panama, SB84-522 | | | |  |
| |  |
| | | |
| |
|
| | Diagnosis:
Clearly separated pelvic fins in the larval stage and the modal fin ray
count of D-VII,10 A-9 and Pect-14-15 indicates Psilotris alepis (one fewer
anal fin ray than second dorsal fin rays). The only Psilotris spp. with
fewer than 16 pectoral fin rays are P. batrachodes and P.
alepis. A more appropriate larval type is identified for P. batrachodes, which has
fewer median fin rays. Other gobies with divided pelvic fins and matching median
fin ray counts have more pectoral fin rays and a different general appearance
(Pycnomma roosevelti and the deep-water
Chriolepis spp. and Varicus
spp.). (PE) G19b | |
| Analogues:
(post-anal fin solitary melanophore, small: <7 mm SL) Within the numerous
solitary post-anal fin melanophore group, there are both divided pelvic
fin taxa as well as a large group of gobies with fused pelvic fins (primarily
the Gobiosoma/Elacatinus spp.).
Among the divided pelvic fin gobies, this larval type is separated from the Pycnomma roosevelti type by having
no dorsal melanophores, and from the Gobulus myersi type by having well-separated
and longer pelvic fins, a long pectoral fin reaching almost to the vent, and a
wider caudal peduncle. In addition to having partially-fused pelvic fins, the
Gobulus myersi larval type has
abdominal midline melanophores. | |
| Description:
Body long, narrow and somewhat thick, with a medium-sized eye and a terminal mouth.
Pectoral fins long, extending to vent. Pelvic fins divided and short, extending
less than halfway to the vent. Dorsal and anal fin bases relatively short, caudal
peduncle short and wide. The caudal fin is wide and rounded. Lightly marked along
the lower body: melanophores along the ventral midline at the pelvic fin insertion
and a large, often dendritic, melanophore on the ventral midline of the caudal
peduncle just behind the last anal fin ray. Internal melanophores occur at the
dorsal surface of the swim bladder and around the gut near the vent. Many individuals
have a bubblewrap-like appearance to the skin. | | |
|
| Psilotris alepis
larva | | 6.3 mm SL | | San
Blas, Panama, SB86-625 | | | |  | | |  | | |  | | |  | | |  |
| |  |
| | | |
|
|
| | Diagnosis:
An individual larva with mostly-divided pelvic fins and the fin ray count
of D-VII,10 A-10 indicates Psilotris amblyrhynchus and overlaps Gobulus myersi. A more appropriate
larval type is identified for G. myersi. This larval type is
essentially identical to the species description for P. amblyrhynchus (Baldwin
and Smith, 2003). | |
| Analogues:
(post-anal fin solitary melanophore, large: >9 mm SL) Within
the diverse solitary post-anal fin melanophore group, there are few taxa with
large larvae: the other large larva is that of Nes longus. 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
only 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 11/11 vs. 13-14/11-13). Other members of the group are
much smaller: Psilotris spp., Gobulus myersi, and Pycnomma roosevelti with divided
pelvic fins and typically other distinctive melanophores, and, with fused pelvic
fins, some Gobiosoma spp.
and Elacatinus spp.,
along with Evermannichthys
spp. (the latter also have a sharply-pointed snout and spiny caudal peduncle
scales). The fused pelvic fin group typicaly have more median fin rays as well. |
| | Description:
Body thick with a large head that is flattened dorsally and a large eye and terminal
large mouth. Pectoral fins medium length, not reaching the level of the vent,
pelvic fins medium length as well and mostly separated, united near the base with
a short membrane, and no pelvic frenum. Dorsal and anal fin bases medium length,
caudal peduncle relatively long and somewhat narrow. Lightly marked along the
lower body: surface melanophores limited to a large prominent dendritic melanophore
at the ventral midline after the last anal fin ray. Internal melanophores are
present along the dorsal surface of the swim bladder. Larvae have a bubblewrap-like
skin. | | |
|
| Psilotris amblyrhynchus
larva | | 12.1 mm SL | | Banco
Chinchorro, Mexico, coll. D. Jones | | |
|  | | |  | | |  | | |  |
| | | |
|
|
| | Diagnosis:
Modal fin ray counts of D-VII,10 A-9 and Pect-16 match
any of a large group of unrelated gobies with either divided pelvic fins (i.e.
Pycnomma roosevelti, Chriolepis
spp., Psilotris boehlki and P. celsus), partially-divided
fins (Gobulus myersi and Gobiosoma
grosvenori), and fused pelvic fins (Barbulifer spp.).
The larvae of most of these gobies have been identified elsewhere in the guide.
This larval type closely matches a transitional recruit of Pycnomma roosevelti from the Saba Bank
in morphology: especially the long body with a small flattened head (and relatively
small round eyes), the placement of the anal fin far back on the body, the wide
caudal peduncle, and the rounded caudal fin. Even the hunched-over appearance,
with the head placement mostly below the lateral midline of the body, occurs in
both my larvae and the juvenile from Saba. In addition, the larval melanophores at the rear edge of the dorsal
and anal fins match markings on the juvenile. (PE) G19a | |
| Analogues:
(post-anal fin solitary melanophore, small: <7 mm SL) |
| | Description:
Body somewhat thick, long, and narrow with a relatively small round eye and a terminal
mouth. In addition, the larva is somewhat "hunched-over", with the head mostly below the level of the lateral midline of the body. Head relatively broad and flattened, not much wider than the caudal peduncle.
Pectoral fins long, dorsal and anal
fin bases short and placed well back on the body, caudal peduncle relatively wide and long. Melanophores limited
to internally on the dorsal surface of the swim bladder and around the gut near
the vent and large solitary melanophores on the caudal peduncle just behind the last dorsal and
anal fin rays. Transitional larvae develop tiny melanophores on the mid-upper
and lower jaw and a scattering of leukophores on top of the head between the eyes. |
| |
|
| Pycnomma
roosevelti larva | | 5.5 mm SL |
| San Blas, Panama, SB84-624a | | |
|  | | |  |
| | | |
|
|
| | Diagnosis:
Modal fin ray counts of D-VII,11 A-10 and Pect-15 and partially-divided
pelvic fins indicate Gobulus myersi and barely overlaps the range of some
Psilotris spp. These genera
have one fewer anal fin ray (sometimes two) than second dorsal fin rays. Pelvic
fins can be fused or halfway-fused in these larvae. The short pectoral fins and
pelvic fins without a frenum, rounded caudal fin, broad head and stocky body of
this larval type fits with Gobulus myersi (or Psilotris
spp.) rather than the other gobies with these fin ray counts and fully-fused
pelvic fins (i.e. some Gobiosoma spp.
and Elacatinus spp.).
The fin ray count of this larval type borders the range but does not match the
Psilotris spp. (too high
for P. alepis; modal pectoral fin rays
too low for P. boehlkei and P. celsus). Confirming the identification
as G. myersi is the white spotting on the upper half of the body from the
top of the head to the caudal fin in transitional larvae: this species is unusual
in being bicolored with light above and dark below (the common name is paleback
goby). Gobulus spp. is a genus with only four species; this one representative
in the Atlantic and three endemic to the eastern Pacific region. Although this
Atlantic species is reported to have fused pelvic fins (without a frenum) as adults,
two of the Pacific Gobulus spp. have partially-fused pelvic fins (without
a frenum), as do these larvae. Fin ray counts in this larval type often vary from
the mode: second dorsal fin elements are often 10 or 12, anal fin elements are
often 9 or 11 and pectoral fin ray counts are often 14 or 16. (Chriolepis
spp. shares the median fin ray count but should have more pectoral fin
rays, longer and separate pelvic fins, and a larger eye). (PE) G8a |
| | Analogues:
(post-anal fin solitary melanophore, small: <7 mm SL) |
| |
Description: Body shape ranges from thin, long and
narrow in earlier-stage larvae to thicker with a large head, medium-sized eye
and a terminal large wide mouth. Pectoral fins short, reaching about halfway to
the vent. Pelvic fins without a pelvic frenum and can be fused or halfway fused,
and short, extending clearly less than halfway to the vent, 4-5 procurrent caudal
fin rays. Dorsal and anal fin bases relatively short, caudal peduncle short and
narrowing. The caudal fin is short, wide and rounded. Lightly marked along the
lower body: melanophores along the ventral midline sometimes at the isthmus, then
just forward of the pelvic fin insertion, followed by from one to seven additional
melanophores along the abdominal midline always ending with a melanophore just
forward of the vent. There are no melanophores along the anal fin base. There
is a prominent large, often dendritic, melanophore on the ventral caudal peduncle
midline just behind the last anal fin ray. Melanophores occur internally along
the dorsal surface of the swim bladder and around the gut near the vent (no melanophores
at the sacculus). Series of transitional larvae show development of the eye from
a somewhat narrowed vertical oval to round (in most specimens the eye is round).
Transitional larvae develop a dark stripe through the eye back to the operculum,
melanophores on the lower jaw, scattered around and within the thorax, and in
a stripe along the sides of the abdominal wall to the vent and continuing along
the base of the anal fin and caudal peduncle to curve around the base of the lower
and central caudal fin rays. There is a conspicuous speckling of leukophores (and
an absence of any melanophores) over the top of the head and extending along the
dorsum of the body onto the caudal fin. Some individuals have a bubblewrap-like
appearance to the skin. | | |
|
| Gobulus myersi
larva | | 5.4 mm SL | | San
Blas, Panama, SB86-407 | | | |  | | |  | | |  |
| Gobulus myersi
larva | | 5.5 mm SL |
| seven midline abdominal melanophores |
| San Blas, Panama, SB86-1103 | | |
|  | | |  |
| Gobulus myersi
larva | | 5.7 mm SL | | slightly
narrowed vertical eye | | San Blas, Panama,
SB87-219 | | | |  |
| Gobulus myersi
larvae | | 5.2 and 5.5 mm SL |
| San Blas, Panama, SB86-503 | | |
|  |
| Gobulus myersi
larva | | 5.5 mm SL |
halfway fused pelvic fins
and short pectoral fins | | San
Blas, Panama, SB86-503 | | | | | | |  |
| Gobulus myersi
larva | | 5.8 mm SL | |
D-VII,12 A-11 Pect-15 | | San Blas, Panama,
SB86-503 | | | |  |
| Gobulus myersi
transitional larva | | 6.0 mm SL |
| San Blas, Panama, SB86-501 | | |
|  | | |  | | |  |
| Gobulus myersi
transitional larva | | 6.0 mm SL |
| leukophores on dorsal side | | San
Blas, Panama, SB87-224 | | | |  |
| Gobulus myersi
transitional larvae | | 6.0 and earlier-stage,
4.9 mm SL | | San Blas, Panama, SB87-224 |
| | |  |
| | | |
|
Goby 23
Chriolepis fisheri
vs. Psilotris
sp. | | | | | | | |
|
Diagnosis: An individual larva with the fin ray
count of D-VII,10 A-10 and Pect-16 falls within the range of a number of regional
species. The state of the pelvic fins is uncertain, but there is no indication
of a frenum, and it is possible that the pelvic fins in this larval type are divided.
Among the seven-spined gobies with fused pelvic fins only Barbulifer spp.
and Gobiosoma
grosvenori have as few as 10 second dorsal fin elements, and both of these
species have one fewer anal fin element. A more appropriate larval type is assigned
to Barbulifer spp.
and other larval Gobiosoma spp.
are very different from this larval type, having very few markings, and well-developed
pelvic frenums (rare individuals of Gobiosoma spes and
G. yucatanum would overlap the fin ray count of this larva). Among the
divided pelvic fin species, a number have modal fin ray counts one different from
10/10 and are therefore candidates for this larval type, including Psilotris
celsus and P. boehlki, Pycnomma roosevelti, and Chriolepis
spp. This larval type does not resemble other larval Psilotris spp. which have relatively
small eyes and are very lightly marked. Pycnomma roosevelti is a goby
with small eyes and a flattened head, which does not match this larval type, and
a somewhat more appropriate larval type is identified. Chriolepis fisheri
is the most likely candidate since these fishes are found in deeper water and
have particularly large eyes. (PE) G23 | |
Analogues: (heavy ventral markings) This
larval type shares the dendritic melanophores along the ventral midline with the
superficially-similar Bathygobius mystacium and B. soporator larval types.
This larval type differs in having the markings continue onto the caudal peduncle
and base of the caudal fin, an area spared in transitional Bathygobius spp. larvae. In addition,
this larval type has seven dorsal spines vs. six in Bathygobius spp. |
|
Description: Body relatively thick, long and narrow with a large eye and a terminal
large mouth. Pectoral and pelvic fin length uncertain, without an obvious pelvic
frenum. Dorsal and anal fin bases medium-length and caudal peduncle medium-length
and relatively wide, 6-7 procurrent caudal fin rays (6 spindly). Heavily marked;
along the ventral midline there are large deep internal melanophores underlying
the isthmus and forward of the pelvic fin base. The abdominal midline is unmarked.
There is a heavy continuous line of large dendritic melanophores along the lateral
abdominal wall continuing along the base of the anal fin and ventral midline of
the caudal peduncle onto the caudal fin. Melanophores line the bases of most of
the caudal fin rays, extending out along the segmented rays. Large dendritic melanophores
lie along the dorsal midline of the caudal peduncle and around the base of the
soft dorsal fin near the fourth element and the last two elements. The lateral
abdominal wall row merges internally with pigment overlying the swim bladder and
extends forward into the head. Head markings include melanophores directly above
the eyeball, near the tip of the upper jaw, between the eye and the mid-upper
jaw, and directly below the eye and just forward of the angle of the jaw, which
also has the typical associated melanophore. The lower jaw has a complex arrangement
of melanophores: there are a pair outlining the lower edge of the dentary on each
side of the midline, a large dendritic pair on each side below the dentary and
then one at the ventral midline halfway down the lower jaw and a pair just forward
of the pair at the angle of the jaw. There are scattered melanophores overlying
the iris. The eye is large and round. | | |
|
| Chriolepis fisheri?
larva | | 7.4 mm SL |
| San Blas, Panama, SB81-196 | | |
|  | | |  | | |  | | |  |
| | | |
|
|
|
Diagnosis: Modal fin ray counts of D-VI,10 A-9 and
Pect-15-17 with fused pelvic fins indicate Bathygobius curacao and Lythrypnus spp.
(and overlaps the range of Coryphopterus alloides).
These genera typically have one fewer anal fin ray than second dorsal fin rays.
Larval Lythrypnus spp.
have radiating bars of melanophores around the eye at transition and a lightly
marked larval type is identified for that genus. Coryphopterus spp.
have lightly-marked larvae and C. alloides
should only rarely have 15 pectoral fin rays and has divided pelvic fins without
a pelvic frenum (this larval type has fused pelvic fins and an obvious frenum).
Lophogobius cyprinoides
and Priolepis hipoliti
share the median fin ray count but have more pectoral fin rays. Bathygobius
spp. are known for having the dorsal-most pectoral fin rays separate from
the rest and filamentous, however this feature is not apparent on larvae. This
larval type has 15-17 pectoral fin rays, indicating B. curacao (B. soporator and B. mystacium have a mode of
19-20 pectoral fin rays). (PE) G14a | |
| Analogues:
(heavy ventral markings) | |
| Description:
Body relatively thin, long and narrow with a large eye and a terminal large mouth.
Pectoral fins long, reaching to vent. Pelvic fins long, reaching almost to the
vent, with an obvious pelvic frenum. Dorsal and anal fin bases medium-length and
caudal peduncle medium-length and sharply narrowing, 7-9 procurrent caudal fin
rays (7-8 spindly). Heavily marked; along the ventral midline there are large
point, stellate, or streak melanophores at the isthmus, one or two forward of
the pelvic fin insertion, and a few behind the pelvic fin insertion along the
abdominal midline. Then there is a variable row of two or three large paired melanophores
spaced along the anal fin base, continuing as a row of three or four large single
melanophores along the caudal peduncle ending at the start of the procurrent caudal
fin rays (the anal fin base and caudal peduncle melanophores often merge into
a single long streak). Dorsal markings consist of a row of paired melanophores
on either side of the dorsal midline: a pair just forward of the spinous dorsal
fin, one just behind, then two or three pairs spaced along the soft dorsal fin,
followed by one to three unpaired melanophores along the dorsal midline of the
caudal peduncle ending well before the start of the upper procurrent caudal fin
rays. Markings on the head consist of a large melanophore outlining the lower
edge of the dentary at the tip of the lower jaw and another at the angle of the
jaw (on pre-transitional larvae). Internal melanophores are present at the base
of the braincase (sometimes around the upper braincase as well), at the sacculus,
along the dorsal surface of the peritoneum and swim bladder, and continuing along
the gut to the vent (often all of these merge into a dark streak arcing through
the body). There is a row of internal vertebral melanophores above and usually
below the vertebral bodies from the mid-body to the caudal peduncle. This streak
can be prominent or mostly obscured by overlying musculature. Some individuals
have melanophores at the base of the lower segmented caudal fin rays extending
out a short distance along the rays. Series of transitional larvae show development
of the eye from round with dorsal and ventral indentations in the iris (mostly
on the dorsal-anterior to ventral-posterior axis, but can vary) to fully round
(most pre-transitional larvae captured have no indentations, and some transitional
larvae have iris indentations). Transitional larvae intensify the surface melanophores
on the iris (covering the upper third of the eyeball and at 2, 5 and 7-8 o'clock)
and develop a stripe from the eye forward across the mid-upper jaw to the mid-lower
jaw and a stripe of melanophores behind the eye across the mid-operculum. Transitional
larvae then develop a speckling of large melanophores and leukophores on the top
of the head to the base of the pectoral fin and a stripe of iridophores across
the operculum and onto the base of the pectoral fin. | |
|
| | |
| Bathygobius curacao
larva | | 5.2 mm SL | | melanophores
in streaks | | San Blas, Panama, SB86-426 |
| | |  | | |  |
| Bathygobius curacao
larva | | 6.8 mm SL | | San
Blas, Panama, SB87-225 | | | |  |
| |  | | |  |
| |  |
| Bathygobius curacao
larvae | | 4.7 and 5.9 mm SL |
| smallest larva above, size comparison |
| San Blas, Panama, SB86-1010 | | |
|  |
| Bathygobius curacao
transitional larva | | 5.5 mm SL |
| with iris indentations | | San
Blas, Panama, SB87-219 | | | |  |
| Bathygobius curacao
transitional larvae | | 5.3 and 4.9 mm SL
| | internal melanophores |
| San Blas, Panama, SB86-1123 | | |
|  |
| Bathygobius curacao
transitional series | | 5.3, 5.4, and 5.9
mm SL | | San Blas, Panama, SB86-426 |
| | |  |
| Bathygobius curacao
transitional larva | | 6.0 mm SL |
| note head neuromasts | | San
Blas, Panama, SB86-1010 | | | |  | | |  | | |  |
| | |
| |
Bathygobius mystacium
(pending dna id) |
| | | | | | |
|
|
Diagnosis: Modal fin ray counts of D-VI,10 A-9 and
Pect-19 with fused pelvic fins indicate Bathygobius soporator or B.
mystacium. This genus typically has one fewer anal fin ray than second dorsal
fin rays. The genus is known for having the dorsal-most pectoral fin rays separate
from the rest and filamentous, however this feature is not apparent on larvae.
This larval type has a mode of 19 pectoral fin rays, indicating either B. soporator or B. mystacium
(a mode of 19-20 vs. 16-17 for B. curacao ). The two species
are usually separated by the former having 37-41 and the latter 33-36 scale rows
later in development. This larval type (with a row of vertebral melanophores)
matches closely the description of a brood of likely B. soporator collected and
raised in Forida by Peters (1983). Since B. mystacium is considered rare
in Florida, Peters' type may represent B. soporator . However, this
row type of larva is rare in my collection while the other type (spot) is very
common, arguing that the spot type is likely B. soporator, which is described
as everywhere very common. Baldwin and Smith (2003) illustrate the spot
type for which a raised individual developed 39 scale rows and therefore was identified
as B. soporator. Furthermore,
transitional recruits from Noronha in Brazil, where only B. soporator is supposed to
occur, have remnants of larval melanophores on the dorsal and anal fin ray membranes,
more similar to the spot type larvae (described in the next species entry). These
conflicting data are anecdotal and the species will have to be distinguished by
DNA analysis underway at present. Other six-dorsal-spined gobies with the same
median fin ray counts (but fewer pectoral fin rays) include Lythrypnus
spp. (14-16), Coryphopterus
alloides (16-17), Lophogobius
cyprinoides (17-18), and Priolepis
hipoliti (18). (ML) G14b | |
| Analogues:
(heavy ventral markings) | |
| Description:
Body relatively thin, long and narrow with a large eye and a terminal mouth.
Pectoral fins long, reaching to the vent. Pelvic fins long, reaching almost to
the vent, with an obvious pelvic frenum. Dorsal and anal fin bases medium-length
and caudal peduncle medium-length and sharply narrowing, 7-9 procurrent caudal
fin rays (7-8 spindly). Heavily marked mostly along the lower and midbody with
markedly dendritic melanophores: there is a large melanophore at the tip of the
lower jaw and at the angle of the jaw. Along the ventral midline there are large
stellate or streak melanophores at the isthmus, forward and behind of the pelvic
fin insertion, then a variable row (paired, one per side) at the anal fin base
and then unpaired extending along the caudal peduncle ending at the start of the
procurrent caudal fin rays. Internal melanophores occur around the lower brain
case and around the sacculus continuing along the dorsal surface of the peritoneum
and swim bladder extending to the gut near the vent (often all of these merge
into a dark streak arcing through the body). There is a row of internal melanophores
surrounding the vertebral bodies and extending for most of the spine from the
level of the vent to the mid-caudal peduncle, often with a discrete row of deep
melanophores along the dorsal vertebral spines as well. There is a prominent and
characteristic matching row of dendritic surface melanophores along the lateral
midline. Melanophores along the dorsal midline are limited to the rear body (vs.
B. curacao ), as two or three
variably-paired large stellate melanophores on either side of the dorsal midline
at the base of the mid to rear soft dorsal fin. Series of transitional larvae
show development of the eye from round with dorsal and ventral indentations in
the iris (mostly on the dorsal-anterior to ventral-posterior axis, but can vary)
to fully round (most pre-transitional larvae captured have no indentations, and
some transitional larvae have iris indentations).with melanophores extending in
patches across the surface of the iris. Transitional larvae develop a stripe of
melanophores from the eye forward to the mid-upper jaw and across to the mid-lower
jaw. As transition continues, the melanophores become essentially a stripe from
the tip of the lower jaw back across the mid-upper jaw to the eye, over the iris,
continuing internally over the base of the braincase to the sacculus continuing
internally to the dorsal surface of the swim bladder then to the vertebral row
of melanophores. A branch stripe extends bilaterally along the internal lateral
abdominal wall to the vent and along the base of the anal fin to the tail. A scattering
of large melanophores and some leukophores develops on the top of the head. |
| |
| | |
| Bathygobius mystacium/soporator
larva | | 5.9 mm SL | | San
Blas, Panama, SB86-425 | | | |  | | |  | | |  |
| Bathygobius mystacium/soporator
larva | | 5.7 mm SL | | San
Blas, Panama, SB86-808 | | | |  |
| |  |
| Bathygobius mystacium/soporator
larva | | 5.9 mm SL | |
with iris indentations | | San Blas, Panama,
SB87-218 | | | |  |
| Bathygobius mystacium/soporator
larva | | 5.3 mm SL | | internal
melanophores | | San Blas, Panama, SB84-523 |
| | |  |
Bathygobius mystacium/soporator
early transitional larva | | 6.3 mm SL |
| internal melanophores | | San
Blas, Panama, SB87-219 | | |  |
Bathygobius mystacium/soporator
early transitional larva | | 5.8 mm SL |
| San Blas, Panama, SB86-808 | | |
|  |
| Bathygobius mystacium/soporator
transitional larva | | 5.9 mm SL |
| San Blas, Panama, SB86-1008 | | |
|  | | |  | | |  |
| | |
| |
Bathygobius soporator
(pending dna id) |
| | | | | | |
|
|
Diagnosis: Modal fin ray counts of D-VI,10 A-9 and
Pect-19 with fused pelvic fins indicate Bathygobius soporator or B. mystacium . This genus
typically has one fewer anal fin ray than second dorsal fin rays. The genus is
known for having the dorsal-most pectoral fin rays separate from the rest and
filamentous, however this feature is clearly not apparent on larvae. This larval
type has a mode of 19 pectoral fin rays, indicating either B. soporator or
B. mystacium (a mode of 19-20
vs. 16-17 for B. curacao). The two species
are usually separated by the former having 37-41 and the latter 33-36 scale rows
later in development. This larval type (spot type, i.e. a single large vertebral
melanophore) matches closely the illustration of presumed B. soporator
by Baldwin and Smith (2003), but is not the row type illustrated as B. soporator
by Peters (1983). The transitional juvenile from Noronha in Brazil, where only
B. soporator is supposed to occur, has remnants of larval melanophores
along the dorsal and anal fin ray membranes similar to this spot type of larvae.
The ID data are anecdotal and the species will be distinguished by DNA analysis
underway at present. Other six-dorsal-spined gobies with the same median fin ray
counts (but fewer pectoral fin rays) include Lythrypnus
spp. (14-16), Coryphopterus
alloides (16-17), Lophogobius
cyprinoides (17-18), and Priolepis
hipoliti (18). (PE) G14 | |
| Analogues:
(heavy ventral markings) | |
| Description:
Body relatively thin, long and narrow with a large eye and a terminal mouth.
Pectoral and pelvic fins long, reaching almost to the vent, with a obvious pelvic
frenum. Dorsal and anal fin bases medium-length and caudal peduncle medium-length
and sharply narrowing, 7-9 procurrent caudal fin rays (7-8 spindly). Heavily marked
mostly along the lower and midbody: there is a large melanophore at the tip of
the lower jaw and one at the angle of the jaw. Along the ventral midline there
are large stellate or streak melanophores at the isthmus, the pelvic fin insertion,
and one to three along the mid-abdomen, then variably paired on either side of
the ventral midline at the anal fin base and then extending along the ventral
peduncle ending at the start of the procurrent caudal fin rays. Internal melanophores
occur around the sacculus and along the dorsal surface of the swim bladder and
around the gut near the vent. Melanophores along the dorsal midline are limited
to the rear body (vs. B. curacao); as one to three
variably paired large stellate melanophores on either side of the dorsal midline
at the base of the mid to rear soft dorsal fin. Long streak melanophores are present
along the membranes of the second to fifth fin rays on both the soft dorsal and
anal fins. There is a single prominent stellate internal vertebral melanophore
at the lateral midline at about the level of the mid soft dorsal fin that ramifies
around the vertebral bodies and extends between and around myomeres and often
up to the surface. Series of transitional larvae show development of the eye from
round with dorsal and ventral indentations in the iris (mostly on the dorsal-anterior
to ventral-posterior axis, but can vary) to fully round (most pre-transitional
larvae captured have no indentations and some transitional larvae have iris indentations).
Early transitional larvae develop a stripe of melanophores from the eye forward
to the mid-upper jaw. As transition continues, the melanophores become essentially
a stripe from the tip of the lower jaw across the mid-upper jaw to the eye, over
the iris and onto the operculum, continuing internally from the sacculus to the
dorsal surface of the swim bladder and around the gut near the vent and along
the anal fin to the tail. Melanophores also develop at the end of the caudal peduncle,
primarily at the base of the central and lower segmented caudal fin rays. Series
of transitional larvae show the eye remaining round, but becoming larger with
the iris developing a dark surface pigmentation layer. Late transitional larvae
develop an additional scattering of large discrete melanophores on the dorsal
half of the head and the operculum, extending to the base of the pectoral fin.
Small iridophores occur in patches behind the eye and in a stripe out onto the
middle rays of the pectoral fin. Patches of small melanophores develop around
the base of the spinous dorsal fin. | | |
| | |
| Bathygobius soporator/mystacium
larva | | 5.5 mm SL | | San
Blas, Panama, SB86-425 | | | |  | | |  |
| Bathygobius soporator/mystacium
larva | | 5.6 mm SL | | single
branching vertebral melanophore | | San Blas,
Panama, SB86-425 | | | |  |
| Bathygobius soporator/mystacium
larva | | 5.7 mm SL | | with
iris indentations | | San Blas, Panama, SB87-218 |
| | |  |
Bathygobius soporator/mystacium
early transitional larva | | 6.0 mm SL |
| San Blas, Panama, SB86-425 | | |
|  |
| |  |
| |  |
Bathygobius soporator/mystacium
transitional larva | | 5.6 mm SL |
| note pelvic fin frenum | | San
Blas, Panama, SB86-616 | | |
|  |
| |  |
Bathygobius soporator/mystacium
late transitional larva | | 5.8 mm SL |
| San Blas, Panama, SB86-426 | |
| |  | | |  | | |  |
Bathygobius soporator/mystacium
transitional recruit | | 7.4 mm SL |
larval melanophore remnants
on dorsal and anal
fin ray membranes | | Noronha, Brazil FN01 |
| | |  | | |  |
| | |
| | |
| |
