The
dartfishes of the family Ptereleotridae have been taxonomically mobile in recent
years and some taxonomists now include them in the wormfish family
Microdesmidae. I place them here alongside the family Eleotridae because they
are gobioids and share the clearly-divided pelvic fins of the eleotrids. Larval
ptereleotrids most closely resemble larvae of the Group
4 gobies. There are only two dartfishes in the region and, since they are
sibling species that vary only in a subtle color pattern, it is likely their larvae
appear identical.
The
sleepers of the family Eleotridae (some use Eleotrididae) are similar to gobies
but have divided and well-separated pelvic fins (photograph of the separated pelvic
fins in
a 12.8 mm SL larval
Eleotris amblyopsis). There
are six Caribbean genera, most with a single species. The eleotrids are all widespread
in the Caribbean, except for Leptophilypnus
fluviatilis, which is an estuarine species recorded only from the central
American coastline from Honduras to Panama and another obscure species, Leptophilypnus
guatemalensis native to inland freshwater rivers in Guatemala (and presumably
with a pelagic larval stage).
Eleotrids are typically
found in tropical freshwater habitats, but they do penetrate brackish and occasionally
even reef environments. Nonetheless, all have an oceanic pelagic larval phase.
Some species get large as adults and can even become gamefishes in the major river
systems of central America. Their larvae, however, are small to medium-sized and
exhibit similar body shapes and marking patterns to the larvae of their goby relatives.
Larval eleotrids share
many basic characters of larval gobies. While most of the true gobies have fused
pelvic fins, several genera have divided pelvic fins like the eleotrids (although
they do not have the fins completely separated at the base as do the sleepers).
Pelvic fin morphology is not always easily apparent on small larvae, but fortunately
there are only a few species of eleotrids in the Caribbean and larval eleotrids
do have a somewhat different appearance from the usual goby gestalt. In addition,
the larvae of most, if not all, of the genera are now identified here.
A unique attribute of
some larval eleotrids is having melanophores on the membrane over the iris that
can expand to essentially cover the shiny surface completely. Also unusual is
the high number of procurrent caudal fin rays, up to 14, in several eleotrid species;
true gobies almost always have 10 or fewer, often many fewer (Pezold 2002). The
one goby exception is found in the larvae of the river gobies Sicydium
spp.. Interestingly, the common factor is freshwater habitat, perhaps
a high number of procurrent caudal fin rays is a product of convergent evolution
for living in fast-flowing streams. Eleotrid larvae also exhibit some of the more
dramatic eye-shape changes during development and at transition found in larval
fishes.
Eleotrid larvae
tend to share basic melanophore patterns and general morphology, and fin ray count
differences are slight. There is also a marked degree of variation within species,
making species identifications more difficult. Some characters common in one larval
type will occur occasionally in another larval type, resulting in few diagnostic
characters; for example, the characteristic melanophore patterns along the jaws
of Eleotris amblyopsis larvae
match closely those found on the late transitional larvae of Erotelis
smaragdus. Typically, a suite of characters in combination serve to distinguish
the larval types and unite transitional series.
The
literature reports of fin ray counts of sleepers can differ by two fin rays or
more, and sometimes disagree on whether there are equal numbers of dorsal and
anal fin rays or more or less. The literature on larval sleepers is also not helpful,
since features common to the entire family are typically cited as unique to one
species or other and line drawings omit other diagnostic features (likely a result
of inadequate sample sizes of highly-variable larvae).
There are complex
neuromast patterns on the head, body and caudal fins of late transitional eleotrid
larvae that can help indicate that two similar larval types must be different
species. These patterns are more developed on juveniles and adults and are commonly
used for taxonomic studies. Unfortunately, the neuromasts can be hard to highlight
on most larvae (photograph below, from the top, larval Erotelis
smaragdus, Gobiomorus
dormitor, and Eleotris amblyopsis).
Ptereleotris helenae
Diagnosis:
Modal fin ray counts of D-VI,23 A-22 Pect-21 indicate Ptereleotris
helenae or P. calliurus. The fin ray
counts are unique to this genus in the region, where no other gobioid exceeds
22 second dorsal fin elements (some Microgobius
signatus individuals can occasionally reach 22 elements and larval Palatogobius
spp. have up to 21). In addition, these other candidates have seven dorsal
fin spines and do not have obviously separate pelvic fins. There are ony two regional
species: P. helenae throughout most of the Caribbean and the almost identical
sibling species P. calliurus from Florida and the Northern Gulf of Mexico.
(U)g21
Analogues:(long goby with long dorsal and anal fins) This larval type has unique
markings for the group, especially a row of melanophores along the base of the
dorsal fins in a pre-transitional larva. Body form is similar to Microgobius
spp., but melanophores along the dorsal midline, especially on the head,
and missing the very common isthmus and pelvic fin base melanophores. The markings
of this larval type are similar to those found in some larval labrisomids
or chaenopsids, but those
families do not have the distinctive separate and short spinous dorsal fins of
the gobioids.
Description:
Body thin, long and narrow with a large eye and a large terminal mouth.
Pectoral fins short, pelvic fins medium-length, extending less than halfway to
the vent, clearly separate with no frenum. 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 dorsal and ventral midlines: melanophores in rows on
the body near the base of the spinous dorsal fin, variably paired and offset from
the midline, then in rows near the base of the second dorsal fin, one offset pair
per fin element, then extending onto the dorsal midline at the caudal peduncle
ending at the start of the procurrent caudal fin rays. Melanophores are present
on some of the central and lower segmented caudal fin rays. There is a row of
melanophores along the anal fin base (variably paired, one per side, a few larger
ones starting at the fifth or sixth element that are fewer than one per ray, then
becoming small and usually one per ray around the tenth element), and then a streak
along the ventral midline of the very short caudal peduncle ending at the start
of the procurrent caudal fin rays. There are no melanophores at the isthmus or
at the pelvic fin insertion. On the head there is a pair of large melanophores
at the rear of the braincase on each side of the dorsal midline. Internal melanophores
are present around the sacculus, along the dorsal surface of the swim bladder
and around the gut near the vent. The eye is large and round.
Ptereleotris helenae
larva
12.2 mm SL
note
separated pelvic fins
San Blas, Panama,
SB82-016
Dormitator maculatus
Diagnosis:
Modal fin ray counts of D-VII,9 A-10 Pect-14 indicate Dormitator
maculatus. This is the only Caribbean eleotrid with more anal fin elements
than second dorsal fin elements (the eastern Pacific sleeper, Gobiomorus
maculatus, shares this feature with a modal fin ray count of D-VI,10 A-11).
D. maculatus is also distinguished from the
other eleotrids by the low pectoral fin ray count and the relatively low numbers
of procurrent caudal fin rays (7-9 vs. 10 or more in several other eleotrids).
D. cubanus has been described as the Cuban
form and D. lophocephalus as the Surinamese
form, although the validity of these species is uncertain. (U) G2
Analogues:
Description:
Body thin, long and narrow with a relatively small, often oval, eye and a terminal
medium-sized mouth. Pelvic fins separate and short, pectoral fins short, dorsal
and anal fin bases short, caudal peduncle long and sharply narrowing, procurrent
caudal fin rays 7-9. Markings mostly along the ventral midline: melanophores usually
as streaks extending from the isthmus to the mid-abdomen, ending at the swim bladder
(which is the full thickness of the abdomen and provides a clear view of the retroperitoneum);
there is often an additional small melanophore on the promontory just forward
of the vent. There are four to six large melanophores along the bases of the last
eight anal fin rays (paired) and continuing as a streak of seven or eight large
melanophores along the ventral peduncle ending at the start of the lower procurrent
caudal fin rays (the last in the series often larger and extends deeper into the
musculature). There are melanophores at the base of most of the lower segmented
caudal fin rays, some variably extending along the length of the lower segmented
caudal rays as well as sometimes on the distal half of the central segmented caudal
fin rays. Head markings consist of melanophores outlining the lower rim of the
tip of the dentary of the lower jaw. Varying proportions of individuals in different
daily collections possess a melanophore at the angle of the jaw, from none to
most. There is usually a prominent "eyebrow" membrane lined with melanophores
overlying the dorsal aspect of the upper third of the eyeball. Additional melanophores
occur on the occasional individual in any combination of the following: on the
proximal membranes of the anal fin elements (usually the third and fourth, rarely
all), overlying the cleithrum visible upon lifting the operculum, or on the outer
operculum near the lower edge on each side. Internal melanophores typically surround
the saccule (in most well-developed larvae) and are present along the dorsal surface
of the swim bladder (none around the gut near the vent). Series of transitional
larvae show development of the eye from a narrowed vertical oval, sometimes tilted
slightly forward (occasionally backward), with the pupil off-center dorsally,
a small posterior-inferior extension of the iris, and often a dorsal indentation
in the iris) to almost rounded, sometimes tilted sharply backward.
Dormitator maculatus
larva
7.9 mm SL
San
Blas, Panama, SB86-1001
Dormitator maculatus
larvae
7.9, 7.6, and 8.0 mm SL
note eye shape variation
San
Blas, Panama, SB86-1001
Dormitator maculatus
larvae
7.9 and 8.0 mm SL
variation in markings including opercular (above),
cleithral (below), abdominal promontory and anal fin ray melanophores
San Blas, Panama, SB86-1002
Dormitator maculatus
larva
7.2 mm SL
note
stubs of separate pelvic fins
San Blas,
Panama, SB86-927
Dormitator maculatus
larva
8.1 mm SL
prominent
"eyebrow" membrane
San Blas, Panama, SB86-1001
Dormitator maculatus
larva
8.2 mm SL
eye
tilted backwards
San Blas, Panama, SB86-1030
Dormitator maculatus
larva
8.1 mm SL
San
Blas, Panama, SB86-1030
Dormitator maculatus
larva
7.4 mm SL
note
three rows of caudal fin papillae
San
Blas, Panama, SB86-1006
Dormitator maculatus
larva
8.1 mm SL
relatively
few procurrent caudal fin rays
San Blas,
Panama, SB86-1001
Eleotris amblyopsis
Diagnosis:
Modal fin ray counts of D-VI,9 A-9 Pect-16 indicate Eleotris
amblyopsis. E. perniger is almost identical (and can co-occur with E.
amblyopsis) but is reported to have a mode of 18 pectoral fin rays with
a range from 16 to 19 (vs. a mode of 16 and a range of 15-18 for E.
amblyopsis)(Pezold 2002). The larval type described here has mostly 15
and 16 pectoral fin rays. This is the only eleotrid genus with as few as 8 or
9 second dorsal and anal fin elements and equal numbers. This taxon historically
has been variably split: although E. pisonis
has been considered the widespread Caribbean species and books refer to it as
such, recent work by Pezold (2002) indicates that the true E.
pisonis is South American, ranging from Orinoco-Venezuela to Brazil. Instead,
E. amblyopsis occurs along the continental
margin from the US to Venezuela and E. perniger
is mostly of the Antilles, but co-occurs with E.
amblyopsis along the Central American coast. Since the species are morphologically
virtually identical, the larvae may be indistinguishable without DNA sequencing.
Two larvae caught together on one day are larger than virtually all of the others,
about 14.5 mm SL, and both have 17 pectoral fin rays; it is possible that they
represent E. perniger, although DNA sequence
analysis will be required for confirmation. (U) G4
Analogues:
Description:
Body somewhat thick, long and narrow (pretransitional individuals can be relatively
wide for this family) with a medium eye and a terminal medium-sized mouth. Pectoral
fins short, reaching only about halfway to vent. Pelvic fins short and clearly
separate. Dorsal and anal fin bases very short and the front and middle rays are
longer than the back rays making a triangular outline to the fin, caudal peduncle
relatively wide and long and there are many procurrent caudal fin rays in a distinct
fleshy fold, from 12-14 in this larval type. Markings mostly along the ventral
midline: melanophores usually as streaks (but often contracted and appear as spots)
extending from the isthmus most of the way to the vent (usually 10 to 15), ending
at the swim bladder (which is the full thickness of the abdomen and provides a
clear view of the retroperitoneum). There is an irregular row of melanophores
along the bases of the last seven or eight anal fin rays (variably paired) and
continuing as three or four streaks along the ventral peduncle ending at the start
of the lower procurrent caudal fin rays. The end of the caudal peduncle is uniformly
covered by a wide bar of large melanophores, usually not extending all the way
to the lower procurrent caudal rays or to the edge of the upper procurrent caudal
fin rays. Melanophores extend out along the proximal lower segmented caudal fin
rays and rarely along the distal portions of the central or upper segmented caudal
rays. Only a rare individual has a small melanophore on the dorsal midline of
the caudal peduncle forward of the start of the procurrent caudal fin rays. Head
markings on all individuals include melanophores at the angle of the jaw, along
the dentary at the tip and below the dentary just to the side of the tip of the
lower jaw. Head markings on most individuals include melanophores on the rim of
the mid-maxilla, on the dentary of the mid-lower jaw, and below the nasal bones.
Prominent melanophores extend over the surface of the iris on the dorsal half
of the eyeball and paired around the base of the eyeball and, when expanded, melanophores
almost cover the iris. Occasional individuals have a hidden melanophore overlying
the cleithrum visible upon lifting the operculum (rarely paired). Internal melanophores
surround the saccule and are present along the dorsal surface of the swim bladder
and paired around the gut near the vent. There is a linear internal melanophore
above the pelvic girdle, perhaps along the ventral postcleithrum and a few internal
melanophores are often present around vertebral bodies near the tail and sometimes
continuing along the hemal spine down to meet the midline melanophores. Melanophores
extend over the iris on the dorsal half of the eyeball and around the sides of
the base of the eyeball and, when expanded, melanophores almost cover the iris.
Series of transitional larvae show the body narrowing and thickening and development
of the eye from a moderately narrowed vertical oval, tilting forward, with the
pupil off-center dorsally and a slight posterior-inferior extension of the iris
(there is also occasionally a marked dorsal and ventral indentation of the iris)
to fully round. Transitional larvae develop a pattern of several discrete melanophores
on the top of the head, at the midline behind the upper lip, and forward of the
eye.
Eleotris amblyopsis
larva
12.0 mm SL
San
Blas, Panama, SB86-1008
Eleotris amblyopsis
larva
12.3 mm SL
early-stage
narrow eye and wide body
San Blas, Panama,
SB86-627
Eleotris amblyopsis
larva
13.3 mm SL
later
rounder eye and narrower body
San Blas,
Panama, SB86-1001
Eleotris amblyopsis
larva
13.2 mm SL
round
eye, no transitional melanophores
San
Blas, Panama, SB84-523
Eleotris amblyopsis
larva
12.3 mm SL
San
Blas, Panama, SB86-627
Eleotris amblyopsis
larva
12.0 mm SL
short
fin bases and triangular fin shapes
San
Blas, Panama, SB86-1008
Eleotris amblyopsis
larva
12.2 mm SL
note
12-14 procurrent caudal fin rays, melanophore at dorsal midline
San Blas, Panama, SB86-1002
Eleotris amblyopsis
larva
13.3 mm SL
three
rows of sensory papillae neuromasts
San
Blas, Panama, SB86-1001
Eleotris amblyopsis
larva
11.7 mm SL
internal
melanophores along vertebral bodies and hemal spines
San
Blas, Panama, SB86-927
Eleotris amblyopsis
larva
12.3 mm SL
San
Blas, Panama, SB86-627
Eleotris amblyopsis
larva
12.4 mm SL
note
indentations in iris
San Blas, Panama,
SB86-1006
Eleotris amblyopsis
larva
13.3 mm SL
note
round eye
San Blas, Panama, SB86-1030
Eleotris amblyopsis
larvae
12.3 and 12.4 mm SL
note melanophores contracted vs. expanded, and sensory
papillae
San Blas, Panama, SB86-1001
Eleotris amblyopsis
larvae
12.3, 12.4, and 12.5 mm SL
melanophores contracted vs. expanded
San Blas, Panama, SB86-1001
Eleotris amblyopsis
larva and early transitional larva below
12.6
mm SL
San Blas, Panama, SB86-627
Eleotris amblyopsis
transitional larva
12.2 mm SL
note expanded melanophores over the iris
San Blas, Panama, SB86-1002
Eleotris amblyopsis
transitional larva
13.2 mm SL
note neuromast development on head, and melanophore
overlying cleithrum
San Blas, Panama,
SB81-019
Eleotris amblyopsis
larva above vs. Gobiomorus dormitor larva below
12.1
mm SL
note neuromast pattern differences
San Blas, Panama, SB86-1002
Gobiomorus dormitor
Diagnosis:
Modal fin ray counts of D-VI,11 or 10) A-10 Pect-16 or 17 indicate Gobiomorus
dormitor or Erotelis smaragdus.
These genera have overlapping fin ray counts and, given the inconsistent ranges
reported in the literature, these cannot be relied on to distinguish the taxa.
Leptophilypnus fluviatilis,
found only in Panama, overlaps the dorsal and anal fin ray counts (with 10/10),
but has 18-19 pectoral fin rays. This larval type differs from Eleotris
amblyopsis larvae in head neuromast patterns and markings and differs
from larval Erotelis smaragdus
in head neuromast patterns, some markings, and having a short base and triangular
outline of the dorsal and anal fins. Larval Guavina
guavina should have a mode of seven first dorsal fin spines and a shorter
and wider shape. Furthermore, the larvae of the eastern Pacific sibling species,
Gobiomorus maculatus, share the character
of melanophores along the base of the upper segmented caudal fin rays, a feature
not seen in pre-transitional individuals of any other eleotrid genus. (PE) G4a
Analogues:
Description:
Body somewhat thin, long and narrow with a large eye and a terminal medium-sized
mouth. Pectoral fins short, reaching only about halfway to vent. Pelvic fins short
and clearly separate. Dorsal and anal fin bases very short and the front and middle
rays are longer than the back rays making a triangular outline to the fin, caudal
peduncle relatively narrow and long and there are many procurrent caudal fin rays
in a distinct fleshy fold, from 11-14 in this larval type. Markings mostly along
the ventral midline: melanophores usually as streaks (but often contracted and
appear as spots) extending from the isthmus most of the way to the vent (about
10), ending at the swim bladder (which is the full thickness of the abdomen and
provides a clear view of the retroperitoneum), most individuals have an additional
midline melanophore on the promontory just forward of the vent. There is a row
of five melanophores along the bases of the last seven or eight anal fin rays
(variably paired) and several more continuing mostly as a streak along the ventral
peduncle ending at the start of the lower procurrent caudal fin rays. There are
melanophores on the membranes only between the first and third anal fin elements.
Melanophores are concentrated at the base of the lower caudal fin segmented rays
extending out along the length of the rays. Unlike pre-transitional larvae of
the other regional larval eleotrids discussed, there are melanophores at the base
of soem or all of the upper caudal fin segmented rays as well. The caudal peduncle
has deep internal melanophores around the point of flexion of the spine which
can connect to the caudal fin base melanophores. Head markings comprise melanophores
at the angle of the jaw and along the lower jaw at the tip and below the dentary
just to the side of the tip (no markings on the upper jaw). There is often an
"eyebrow" membrane lined with melanophores overlying the dorsal aspect of the
upper third of the eyeball. There is a melanophore overlying the cleithrum visible
upon lifting the operculum (paired). Internal melanophores surround the saccule
and are present along the dorsal surface of the swim bladder and paired around
the gut near the vent. Some individuals show several of the ventral midline melanophores
extending internally along the hemal spine in the body segments posterior to the
the vent. Series of transitional larvae show development of the eye from a moderately
narrowed vertical oval with a slight posterior-inferior extension of the iris
to fully round.
Gobiomorus dormitor
larva
12.1 mm SL
Fin
ray count: 10/10 16
San Blas, Panama,
SB86-1002
Gobiomorus dormitor
larvae
12.2 and 12.1 mm SL
San Blas, Panama, SB86-1030
Gobiomorus dormitor
larvae
12.2, 12.1 and 12.1 mm SL
San Blas, Panama, SB86-1030 and 1002
Gobiomorus dormitor
larva above vs. Eleotris amblyopsis larva below
12.1
mm SL
note neuromast pattern differences
San Blas, Panama, SB86-1002
Erotelis smaragdus
Diagnosis:
Modal fin ray counts of D-VI,11 A-10 (rarely 10/9) Pect-17 indicate Erotelis
smaragdus or Gobiomorus dormitor.
These genera have overlapping fin ray counts, and given the inconsistent ranges
reported in the literature, these cannot be relied on to distinguish the taxa.
Leptophilypnus fluviatilis,
found only in Panama, may rarely overlap the dorsal and anal fin ray counts (10/10),
but has 18-19 pectoral fin rays. This larval type differs from both Eleotris
amblyopsis and the Gobiomorus
dormitor larval type in head neuromast patterns, markings, and most notably,
in having a longer and lower dorsal fin with the rays of even length vs. the triangular
outline of the dorsal and anal fins in those two other larval types. This is an
important character in distinguishing Erotelis smaragdus: both juveniles
and adults have a much longer and lower dorsal fin in than do other eleotrids.
In addition, this larval type is almost identical to the larval type corresponding
to the Pacific sibling species, Erotelis armiger,
which fortunately has a unique fin ray count for the family (D-VI,13 A-11). Guavina
guavina should have a mode of seven first dorsal fin spines and has a
shorter and wider shape. There is a questionable species described only from a
drydock in the Canal Zone named E. shropshirei,
the status of which is uncertain. (PE) G17
Analogues:
Description:
Body very thin, long and narrow with a medium eye and a terminal medium-sized
mouth. Pelvic fins separate and short, pectoral fins medium length, dorsal and
anal fin bases medium length (the base of the second dorsal fin can be almost
the same length as the caudal peduncle behind the fin (or at least more than two-thirds)
and the rays are of roughly even length), caudal peduncle long and relatively
narrow and there are many procurrent caudal fin rays in a distinct fleshy fold,
typically about 12-14 in this larval type. Markings mostly along the ventral midline:
melanophores usually as streaks (but sometimes contracted and appear as spots)
extending from the isthmus most of the way to the vent (about 10), ending at the
swim bladder (which is the full thickness of the abdomen and provides a clear
view of the retroperitoneum). There is a row of melanophores along the bases of
the fourth and fifth and then the last several anal fin elements (variably paired)
and continuing as several streaks along the ventral peduncle ending at the start
of the lower procurrent caudal fin rays. There are melanophores on the membranes
between all of the anal fin elements. There is a gap of melanophores at the start
of the ventral procurrent caudal fin rays followed by a patch of melanophores
on the mid procurrent rays and then heavy pigmentation over the bases of the lower
segmented caudal fin rays extending along the full length of the lower segmented
caudal rays as well as on the mid and distal portions of the central and sometimes
the upper segmented caudal fin rays. The central and upper portion of the end
of the caudal peduncle is covered by surface melanophores. A small and often inconspicuous
melanophore is frequently present on the dorsal midline of the caudal peduncle
just forward of the start of the procurrent caudal fin rays. Head markings on
all individuals include melanophores at the angle of the jaw, along the dentary
at the tip and below the dentary just to the side of the tip of the lower jaw.
Head markings on some individuals include melanophores on the inside dentary of
the mid-lower jaw, the rim of the mid-maxilla, the tip of the upper jaw, and below
the nasal bones. Melanophores extend over the iris on the dorsal half of the eyeball
and around the sides of the base of the eyeball and, when expanded, melanophores
cover most of the outer half of the iris ring. Many individuals have a hidden
melanophore overlying the cleithrum visible upon lifting the operculum (variably
paired) and most have a melanophore along the insertion of the lowest pectoral
fin ray. Internal melanophores surround the saccule and are present along the
dorsal surface of the swim bladder and paired around the gut near the vent. There
is a linear internal melanophore above the pelvic girdle, perhaps along the ventral
postcleithrum. There are prominent internal streaks extending along the hemal
spines from the vent level rearwards (starting at the ventral midline melanophores
and extending upwards toward the vertebral bodies and then occasionally even above).
Series of transitional larvae show development of the eye from a moderately narrowed
vertical oval, no tilt, with the pupil off-center dorsally and a posterior-inferior
extension of the iris and/or melanophores (there is often a marked dorsal and
ventral indentation of the iris as well), to fully round. Transitional larvae
develop a pattern of large discrete melanophores speckling the upper half of the
head, around the nasal bones and along the upper and lower jaws as well as internally
around the posterior brain case. Surface melanophores develop along the lateral
midline from the caudal peduncle forwards.
Erotelis smaragdus
larva
11.2 mm SL
San
Blas, Panama, SB87-227
Erotelis smaragdus
larva
11.3 mm SL
note
internal melanophores
San Blas, Panama,
SB86-702
Erotelis smaragdus
larva
11.2 mm SL
note
internal melanophores
San Blas, Panama,
SB86-826
Erotelis smaragdus
larva
11.4 mm SL
internal
melanophores along hemal spines
San Blas,
Panama, SB87-302
Erotelis smaragdus
larva
11.4 mm SL
note
iris extension
San Blas, Panama, SB86-1030
Erotelis smaragdus
larva
10.3 mm SL
note
indented iris and 12-14 procurrent caudal fin rays
San
Blas, Panama, SB86-808
Erotelis smaragdus
larva
11.1 mm SL
note melanophores at cleithrum, lowest pectoral fin ray insertion, and internal
pelvic fin process
San Blas, Panama,
SB86-109
Erotelis smaragdus
larvae transitional series
11.4, 10.8,
and 11.3 mm SL
San Blas, Panama, SB86-1030
Erotelis smaragdus
early transitional larva
10.8 mm SL
San Blas, Panama, SB86-1030
Erotelis smaragdus
transitional larva
11.3 mm SL
San Blas, Panama, SB86-1030
Guavina guavina
Diagnosis:
Analogues:
Description:
Leptophilypnus fluviatilis ?
Diagnosis:
An individual larva with the fin ray count of D-?,11 A-10 could represent
any of Erotelis smaragdus,
Gobiomorus dormitor, Guavina
guavina, or Leptophilypnus fluviatilis (Leptophilypnus
mindii is a synonym (Thacker and Pezold)). These genera share overlapping
median fin ray counts and given the inconsistent ranges reported in the literature,
these cannot be solely relied on to distinguish the taxa. The fin ray count is
also shared with many true gobies, however this larva is much longer and narrower
any seven-spined goby candidate with these median fin ray counts and also does
not resemble the larvae of any six-spined candidates (Coryphopterus
personatus and Priolepis
robinsi). Larvae of the gobies with 12 or more median fin elements (the
long gobies) do have the long and narrow body shape, but all have a long soft
dorsal fin base which is clearly not present in this larva. Furthermore, the markings
on this larva are consistent with the other eleotrid larval types described, especially
the combination of the outlining of the lower rim of the dentary at the tip of
the lower jaw, the mid-abdominal ventral midline streak, and the heavy markings
on the lower caudal fin segmented rays (quite similar to Dormitator
maculatus, but that species has D-9 A-10, a pigmented membrane over the
upper eyeball, a smaller eye, and a slightly longer and thinner body at a similar
size). This specimen could possibly represent an earlier-stage larva of either
Gobiomorus dormitor or
Erotelis smaragdus, however
identified larvae of these genera at a matching size have all the characteristic
markings of larger specimens. Larval Guavina
guavina are shorter and wider. (PE)
Analogues:
Description:
Body thin, long and narrow with a small a somewhat narrowed vertical oval oval
eye and a terminal small mouth. Pelvic fins short, pectoral fins short, dorsal
and anal fin bases short, caudal peduncle long and relatively narrow. Markings
mostly along the ventral midline: melanophores usually as streaks at the isthmus,
the pelvic fin insertion, and the mid-abdomen. There are four discrete melanophores
along the base of the anal fin and then continuing as a streak of five melnophores
along the ventral peduncle ending near the start of the lower procurrent caudal
fin rays. Melanophores are present at the base of most of the lower segmented
caudal fin rays extending well out along the fin rays. Head markings are limited
to melanophores at the angle of the jaw and outlining of the lower rim of the
dentary at the tip of the lower jaw. Internal melanophores are present along the
dorsal surface of the swim bladder.
