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| Triplefins
are tiny blenny-like fishes that skate around
over rocks and coral heads on shallow reefs
everywhere in the Caribbean. There is only
one regional genus, Enneanectes,
with five widespread and very similar-appearing
species. There are likely several more undescribed
species in the region. Adults are identified
to species by spine lengths, scale characters,
and color patterns; all characters developing
after settlement. My DNA sequencing on the
group reveals a greater variation in color
patterns (and dorsal-fin spine lengths) than
appreciated, and, unfortunately, these characters
are prominent in keys to the genus. Larvae
of the triplefin species share most features
and, since there is some overlap in fin-ray
counts, DNA sequencing would be necessary
for most individual species identifications.
Nevertheless, modal fin-ray counts do differ
and larvae can often be narrowed down to one
or two candidate species. |
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| Larval
tripterygiids resemble labrisomid
larvae, differing mainly by having prominent
melanophores on the upper caudal peduncle
and three separate dorsal fins. They can be
recognized by their their pointed snout, long
dorsal and anal fins with flexible spines
(dorsal fin divided), a short and narrow caudal
peduncle, long strand-like pelvic fins, the
absence of spines on the head, and light markings
(basically a row of melanophores along the
anal fin base and along the dorsal midline
of the caudal peduncle). Larval tripterygiids
have large round eyes, in contrast to many
labrids,
scarids,
and gobies,
in which the eye can be small or narrowed. |
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| Triplefins
have demersal brooded eggs and hatch as well-developed
larvae around 4-5 mm SL. The early-stage larvae
can be recognized by a moderately long and narrow
body with a small pointed head, medium mouth, prominent
jaw angle, large rounded eye, no head spines, snout-to-vent
length slightly less than half of body length, long
fin bases, and early-forming posterior dorsal and
anal-fin elements. Pigmentation is distinctive,
with a surface melanophore at the midline over the
rear braincase and a short row of two or three melanophores
at the dorsal and ventral midlines of the caudal
peduncle. In addition, there is a row of three ventral
midline melanophores along the base of the posterior
portion of the developing anal fin. There are internal
melanophores at the sacculus, over the swim bladder,
and around the gut near the vent. |
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| Enneanectes sp.
larva | | 4.7 mm SL | | early-stage
larva | | San Blas, Panama, SB86-1227 |
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| Diagnosis:
Three dorsal fins with a modal fin-ray count
of D-III,XI,7-8 A-II,15 P-14 indicates Enneanectes;
the 14/15 pectoral-fin/anal-fin soft ray combination
is typical of Enneanectes altivelis. In contrast, E.
pectoralis and E. jordani have a mode
at 15/15, E. boehlkei and E. atrorus
have a mode at 15/16-17. |
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| Description:
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| Enneanectes sp.
larva | | 8.6 mm SL | | internal melanophore pattern | | San Blas, Panama, SB86-509 | |  |
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| Diagnosis:
Three dorsal fins with a modal fin-ray count
of D-III,XI,7-8 A-II,16 P-15 indicates Enneanectes;
the 15/16 pectoral-fin/anal-fin soft ray combination
is typical of E. boehlkei and E. atrorus.
E. boehlkei is the most common shallow-water
triplefin found in Panama. |
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| Description:
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| Enneanectes sp.
larva | | 8.6 mm SL | | internal melanophore pattern | | San Blas, Panama, SB86-509 | | |
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