Note (April 2008): My webguide
is a work in progress, with daily edits and new
family pages and photographs added continuously.
I am concentrating on the early life history stages
of snappers, gobies, damselfishes, and labrids
right now. My long-range plan is to first photograph
my Caribbean larval collections, then go on to
my eastern Pacific and Indo-Pacific collections.
Why keep my guide on the web? The main reason is that books and papers require
that information be frozen in time; essentially a snapshot of knowledge at a particular
moment. We used to accept this as inevitable and many of us probably don't even
think about it. But it is clear that scientific information is continuously being
updated and remodeled and it is somewhat discordant, and certainly inefficient,
to produce and package the results in an occasional bolus. Unfortunately, most
of us accept that authors will have their additions, changes, and errata somewhere
on their desk and inaccessible (we hope only until the next edition). Even worse,
when the subject is a compendium of information, such as a guide, authors often
wait until it is in some form "complete" before submitting it to publication.
Woe be unto the perfectionist in this case, for it may take a lifetime for some
people to decide they are ready. That is all 20th-century thinking- there is no
reason in the age of the internet not to have a work in progress made generally
accessible.
INTRODUCTION
Virtually all of the thousands
of species of tropical reef fishes have a larval stage that spends weeks to months
in the open ocean before returning to the reef to settle. This transition from
pelagic larvae to settled juveniles is a profoundly important time for reef fishes.
During this settlement transition, which usually occurs on moonless nights, the
larvae have critical decisions to make: they need to select an appropriate habitat,
avoid the ubiquitous predators and change their shape and color for life on the
reef. Understanding this early-life-history process is clearly important to understanding
the population dynamics and, more broadly, the biogeography, ecology, and evolution
of coral reef fishes.
Despite its undoubted
importance, this transition has not been comprehensively studied and one of the
reasons this may be true is the lack of information on late-stage larvae. I have
been collecting these larvae, mostly by netting at a nightlight directly over
the reef, but also with crest-nets and other techniques for many years. In addition,
I have focused my daytime collecting on what some of us call "new recruits", the
recently-transformed juvenile fishes that suddenly appear in the morning on the
reef.
For some reason,
almost all of the reef-fish larvae I collect at a nightlight are late-stage larvae
ready to settle onto the reef. This is not an artifact of their attraction to
the light: I have towed plankton nets in the area and I get a similar size complement
of larvae. In addition, other techniques to collect incoming larval fish, such
as crest nets, yield the same size categories of larvae.
The simplest
explanation for this phenomenon is that larval fish that are ready to settle somehow
maneuver themselves into on-reef currents, perhaps just by rising to the surface
water layer. There has been recent research indicating that reef-fish larvae are
good swimmers and can actively orient towards reefs. However they manage it, almost
all of the larvae I capture are around the particular settlement size range for
their species. This can be very helpful in identifying larvae.
REFERENCES
There are a number of excellent
books on larval identification and the early life history stages of fishes. Most
include copious drawings of reef-fish larvae and also focus on the earlier stages
of fish larvae: Jeff
Leis at the Australian Museum has published his opus (or opuses) with comprehensive
coverage of the Indo-Pacific species of reef and shore fishes.
For the Atlantic,
there is the new larval fish book edited by Bill Richards:
Richards, W.J.
(2005) Early Stages Of Atlantic Fishes: An Identification Guide For The Western
Central North Atlantic (Marine Biology)
It covers pelagic fishes and deepwater
fishes as well as shore and reef species and captures the state of the art from
a couple of years ago. Lastly, the classic book by Michael Fahay (1983), the Guide
to the Early Stages of Marine Fishes Occurring in the Western North Atlantic Ocean,
deals mostly with the temperate ichthyoplankton of the Atlantic coast of the US.
Larval descriptions have been illustrated with line drawings for many years and
even now virtually all books and scientific papers use line drawings almost exclusively.
There are a few benefits to the use of drawings for early stage fishes; for example,
otherwise-transparent details such as head spines and pectoral fin rays can be
highlighted. Nevertheless, it is most likely that the main reason for line drawings
is the cost of printing photographs and the necessity to limit the number of pages
and illustrations in the publishing process. But, in the near future, and however
resistant we may feel to change, libraries certainly will be merged into central
databases and printing presses and paper may well go the way of the neighborhood
bookstore. Line drawings may seem as quaint as the watercolors used for the illustrations
in 19th century species descriptions.
There are
many limitations to line drawings. Perhaps the most problematic is that melanophores,
especially small or delicate ones, disappear against a black line drawing and
these melanophores are often the most critical element in larval identifications.
The idealization of the drawing can also distort the real appearance of the larvae,
emphasizing outlines and de-emphasizing shading, form, and especially color. Furthermore,
there is usually marked variation in the appearance of fish larvae, both functional
(such as melanophores expanded or pinpoint) and inherent (incomplete melanophore
complements are common). This variation among individuals certainly argues against
presenting an ideal. In addition, the development of metamorphic markings and
morphological changes is a continuous process and it is, of course, impossible
to pick one or two images to capture the information.
Now that digital
photography and web publishing has streamlined the use of photography, it is possible
to present many illustrations of a single larval type and get around the limitations
of choosing a single or only a few diagnostic images. I hope to emulate the actual
process of identification, which is to use a variety of views and backgrounds
to create a gestalt that quickly identifies a larval type without following a
key or character list to arrive at a diagnosis.
Along a similar
vein, most of the literature to date bravely (or is it quixotically) tries to
verbally describe larval shapes and melanophore patterns. More text is usually
favored over more illustrations, probably because of the decreased costs of publication.
This obviously limits the amount of information captured since it is technically
impossible to render three-dimensional shapes and patterns into words. Furthermore,
the location of markings and structures can only be given relative to
other landmarks
and is always limited in precision by the amount of text that can be printed,
or even tolerated, by a reader. I therefore will try to avoid the temptation to
add reams of description to the photographs, but I will insert a hopefully pithy
verbal description when it is necessary to highlight relevant features.
I present the photographs
of larvae usually with a dark background, sometimes along with a matched photo
taken against a light background so that the black melanophore pattern, and especially
internal melanophores, can be seen. Photographs against dark backgrounds, like
line drawings, can hide the small or edge melanophores that are often diagnostic
for larval types. I also include detail photographs on pertinent features of the
larvae that may be critical to identification or of specific interest. If there
are transitional forms of interest, photographs of those are included. I also
hope to add images of new recruits, especially for those groups with many similar
species and distinctive juvenile markings.
THE
DEFINITION OF LARVAE
Please
note that most reef-fish biologists use the loose definition of the word "larvae",
i.e. the stages of development before settlement to the reef, if they show
a morphological difference from settled juveniles.
This
definition of early stage fishes excludes the pelagic juveniles of some species
who are typically indistinguishable from reef-based juveniles and often float
with drift objects: these fishes have essentially settled onto a drifting platform.
As one can imagine, the few species that do this regularly are annoying to us
mainly because they defy the usual interpretations of what defines "larvae", "settlement",
and "pelagic larval duration". Reef fishes in this category include the Sargassum
algal drift-associated juveniles, to some degree or another: triggerfishes (Balistidae),
the damselfishes Abudefduf
spp. (Pomacentridae), filefishes (Monacanthidae),
barracudas (Sphyraenidae), triplefins (Lobotidae), pipefishes and seahorses (Syngnathidae),
and needlefishes (Belonidae).
Another intriguing discovery
is the occasional pelagic adult reef fish. This is new information and may explain
the sometimes contradictory findings of the degree of larval dispersal derived
from study of larval pelagic durations versus the observed degree of gene flow
in phylogenetic studies. The elusive pelagic adult is quite intriguing, and I
hope to pursue this curious creature in future expeditions. Several sources of
information indicate that this is happening, although to what degree is completely
unknown. The original observation was by Ross
Robertson who saw adults of the slingjaw wrasse, Epibulus
insidiator, rising off of reefs and drifting away offshore (in Palau, a
part of Micronesia, in the Western Pacific). Then there have been records of the
rare adult reef fish caught in light traps far offshore (reports from the Great
Barrier Reef) and observations of adult reef parrotfishes in schools in pelagic
waters far from reefs (Enric Sala reports from diving in Cuba).
The
significance of this phenomenon is unknown. Perhaps it is a way of relocating
among reef systems for more advantageous feeding or reproduction, although this
would require that the likelihood of returning to a reef outcrop be greater than
the likelihood of being eaten by a tuna... somewhat hard to imagine. Alternatively,
some pelagic adults may not be reef emigrants, but could be lost pelagic juveniles
approaching maturity, perhaps associated with drift structure for protection,
and haplessly waiting for a chance encounter with a reef. Larval mortality schedules
must have a tail to the distribution and thus permit some small but real fraction
of pelagic larvae to persist through transformation (if obligatory at some point)
and even grow to adulthood offshore.
HOW DO
I IDENTIFY REEF FISH LARVAE?
This
is perhaps the most common question I am asked, since there is a bewildering variety
of fish larvae in almost any collection. In addition, the possible candidates
for any particular larva in the Caribbean or the eastern Pacific include a thousand
reef-fish species, and perhaps another thousand other shorefish species and deepwater,
midwater, and pelagic fishes as well. That total rises to many thousands as one
approaches the center of diversity near Indonesia in the central Indo-Pacific.
Fortunately, larval fishes, especially at later stages, are not uniform or even
broadly similar; in fact they can often have even more divergent characters
than do the adults. For example, virtually all reef fishes have round eyes after
settlement, while their larvae can have widely-varying eye morphologies, often
narrowed or tilted and sometimes exhibiting bizarre shapes. In addition, some
taxa have larvae with greatly-extended fin spines or rays, sometimes many times
longer than the larva itself. There is also a great diversity in spine development,
with many larvae having complex spine ornamentation on the head or fins, often
lost or inconspicuous on adults. Finally, an important character at higher taxonomic
levels for fishes is the number of myomeres, the muscle segments making up the
body. These are hidden under pigment and skin in juvenile and adult fishes, but
are clearly obvious and countable in most larval fishes.
Some
taxa fortunately develop the typical juvenile appearance as late-stage larvae
and are thus easy to identify from known-juvenile markings and coloration. Typically
these larvae still do show some subtle adaptations to pelagic life, often a silvery
sheen and shades of black, gray and brown or red instead of the usual bright colors.
Red does not penetrate seawater well and would appear gray, especially in low-light
conditions. Examples of fishes using this strategy include the angelfishes (Pomacanthidae),
the butterflyfishes (Chaetodontidae),
and the squirrelfishes (Holocentridae). A larval Pomacanthus arcuatus,
only 8.2 mm SL, is pictured at right.
Others live among drift
algae and are camouflaged by markings similar, but not identical, to those of
settled juveniles. The camouflage is an adaptation to avoid being eaten by the
ubiquitous pelagic predators which target floating objects in the open ocean,
such as tunas and mahi-mahi (dolphinfish). Larvae following this strategy include
some pipefishes and seahorses (Syngnathidae),
triggerfishes (Balistidae),
and filefishes (Monacanthidae).
Identification to genus
and species in larvae with a more generic appearance can be much more difficult
(excuse the pun). Most generic types of reef-fish larvae are transparent and very
small and, while they are alive, look just like tiny slivers of glass with eyes.
When there are just a few genera or species in a group, the fin ray counts are
usually diagnostic to species. In some of the more
speciose
groups with large sets of closely-related species, such as the gobies (Gobiidae)
and the gobioids (Gobioidei), the scaled
blennies (Labrisomidae), the snappers
(Lutjanidae), the seabasses and groupers
(Serranidae), as well as parrotfishes
(Scaridae), wrasses (Labridae),
and some damselfishes (Pomacentridae),
the number of possible species can be overwhelming and I have to resort to some
other method of identification. There are a variety of ways to do this, some simple
and some using the latest molecular techniques.
FIRST,
USE THE PROCESS OF ELIMINATION...
Most
reef-fish larvae do resemble juveniles and adults in basic form, and, especially,
in the number of fin spines and rays and myomeres. This is the primary method
of identification for early life history stages and works almost all the time
for family, most of the time for genus, and often for species.
Of
course, this is essentially a process of elimination and it is much easier in
the Caribbean, with only a few hundred possible candidates, versus the Indo-Pacific
where there can be thousands of reef-fish species occurring at one particular
site. The eastern Pacific region is generally similar to the Caribbean in numbers
of reef-fish species. The majority of my specimens are Caribbean, most from the
San Blas Islands of Panama, so I will start developing the guide for these fishes.
Other Caribbean sites from which I have collected include Belize, Puerto Rico,
and St. Thomas. I have also collected fishes at the Brazilian island of Fernando
de Noronha, where there is an unusual complement of reef fishes, some endemic
and some widespread Caribbean forms.
A particularly useful
variant of the process of elimination is the examination of fishes from isolated
regions where only a subset of the group is present (i.e. depauperate locations).
This is a very useful method in some groups where the larvae of similar species
can be very difficult to separate. For example, there are numerous very similar
gobies of Coryphopterus
spp. in the Caribbean, but only one species, C.
glaucofraenum, ranges south to Noronha in Brazil.
Another
useful variant is using the similarity with sibling species in the eastern Pacific
Ocean to refine the process of elimination. When identifications of larval types
becomes difficult because there are several Caribbean species that all share fin
ray counts, the situation may be different on the Pacific side of Central America.
The isthmus of Panama rose about three million years ago, and there are numerous
reef-fish genera with species on both sides of the isthmus, often as very similar
species pairs or "sibling species". On the other hand, some genera occur on only
one side, and the presence (or even absence) of a particular larval type on
one
side or the other can contribute to the process of elimination and confirm an
identification. For example, the sleeper Erotelis
smaragdus shares its fin ray counts with other Caribbean sleepers, making
it a problem for identification. But, in the eastern Pacific, the sibling species
Erotelis armiger has a unique fin ray count among the eastern Pacific sleepers.
I now have collected a series of sleeper
larvae with
that fin ray count from near the Galapagos Islands, and they are almost identical
to the putative Erotelis smaragdus
larval type... thus confirming the identification for the Caribbean larval type.
Another example is an unusual Caribbean goby larval type with a fin ray count
matching several Ctenogobius
spp., but also the monotypic Evorthodus
lyricus. Again, I have collected an identical larval type from the eastern
Pacific Ocean, where, fortuitously, there are only two Ctenogobius spp.
(neither of which match the fin ray count), but there exists the sibling of the
Caribbean Evorthodus species, Evorthodus minutus, with the appropriate
fin ray count. That confirms the identification of the Caribbean larval type as
Evorthodus lyricus.
THEN,
LOOK FOR MISSING LINKS (TRANSITIONAL LARVAE AND TRANSITIONAL RECRUITS)
On close examination, many
larval types have very characteristic and remarkably consistent patterns of black
spots (melanophores). Often, they also have specific patterns of other chromatophores.
Pigment cells in fishes include the classic melanophores which comprise black
and brown spots, iridophores which are mirror-like spots that simply reflect light
and often appear silvery, leukophores which are white, and xanthophores which
range from yellow to orange to red. Unfortunately xanthophore pigments dissolve
rapidly in solvents and are not usually preserved.
Now
why would these markings be so prominent and so specific? I think pelagic larvae
use these for species identification. Perhaps they prefer to travel together while
in the open ocean and settle together. I have noticed that sometimes several new
recruits of a particularly uncommon species will show up on the same rock on the
same morning, with no other recruits for miles around. Interesting....
Fortunately,
in most reef fishes the larval markings are quite different from the juvenile
markings. Larval melanophores are typically large, often stellate, individual
black spots that extend below the skin surface. These markings are replaced during
the settlement transition by metamorphic melanophores in the patterns shown by
juveniles on the reef. These arrays of additional melanophores (and sometimes
leukophores and iridophores), are usually much smaller and right at the skin surface.
In addition, they are typically numerous and in dense patches that often begin
on the head and develop posteriorly following the pattern of the juvenile markings
of the species. This Labrisomus haitiensis transitional larva shows the
prominent three larval melanophores surrounded by the patches of fine metamorphic
melanophores. In many species, this transition can take days and often the larval
markings coexist with the developing juvenile patterns. These metamorphic melanophores
are invaluable for identifications.
So
an excellent method of identifying larvae is to find the occasional pelagic larva
that has started to transform and is developing the characteristic juvenile markings
while still in the water column. Alternatively, I often have collected new recruits
on the reef that still have some identifiable larval melanophore patterns, i.e.
transitional recruits. Both of these forms
of missing links can indicate what species that type of larvae represents.
THE GOLD STANDARD:
DNA SEQUENCE MATCHING
The most recent advance is the use of DNA sequencing to identify larvae. This
technique is rapidly becoming the gold standard for larval identification. Once
a library of sequences is known for a group of species, then individual larvae
can be sequenced and matched to the known species. This method can be expensive
and requires a full set of species-specific sequences for the group, which is
not always easy to assemble. Nevertheless, I have started a comprehensive larval-adult
matching project using mitochondrial DNA sequences and have started to resolve
some of the more tricky ID situations, such as the damselfish Stegastes
spp., the labrid Halichoeres
spp., the parrotfish Sparisoma
spp., the snapper Lutjanus
spp., and the gobies Bathygobius
spp., Lythrypnus
spp., and Coryphopterus
spp. In addition to confirmatory IDs, sequence analyses are wonderful
tools for discovering new and/or cryptic species: indeed, recent analyses I have
done have discovered cryptic species among the Caribbean Coryphopterus
spp. and that two cryptic species of bonefishes, Albula spp., coexist
in equal numbers in my Panama collections. Another benefit of sequencing reef
fishes is discovering surprising and unexpected patterns of relatedness. My sequences
for the labrids showed that Halichoeres
maculipinna is only distantly related to the other Halichoeres
spp. and may be closer to the Thalassoma
spp. In addition, with collections over wide geographic ranges, one can
assess the degree of genetic divergence of isolated island populations. My sequences
reveal that this divergence sometimes seems to show little relation to the duration
of the pelagic larval phase. I cannot really explain this counter-intuitive finding
and it surely indicates that the relationship between dispersal and speciation
is not a simple one (to say the least). Clearly, a plethora of profound insights
are about to arrive with the advent of widescale DNA sequencing of reef fishes.
FINALLY, AQUARIUM
RAISING OF LARVAE
Another
method is to isolate the larva and raise it in an aquarium tank until it develops
identifiable juvenile markings. This method can be labor intensive and requires
the larva not to be so delicate that it dies from handling. In addition, there
is a piscine Heisenberg Uncertainty Principle, which is that one cannot keep the
larva in preservative and also raise it alive. If it is possible to examine the
living larva close enough (and even photograph it) and then raise it, an identification
can be made.
An alternative, although much
more intensive and expensive, method to document the early life history of reef
fishes is to raise the fish from the egg through the larval period in the laboratory.
This is being achieved more recently as techniques for feeding notoriously delicate
reef-fish larvae are perfected. There are some indications, however, that laboratory-raised
larvae may look somewhat different from "real" larvae since they are certainly
living in unnatural conditions and may grow at different rates. In addition, they
would be undoubtedly confused as to when and whether they should enter transition.
TERMINOLOGY
AND LAYOUT OF LARVAL IDENTIFICATIONS IN THE GUIDE
Identifications
will be presented to the lowest taxonomic level of which I am reasonably sure.
A question mark after the genus or species name indicates that I am not reasonably
sure of the identification. This could mean that the identification is simply
of the most likely species without any other good reason to choose it, or, less
commonly, that the identification fits by some criterion but I am suspicious because
it doesn't "look right". Some larval types may, of course, include other closely-related
species that have identical larval features. If this is the case, it will be indicated
by a plus sign after the species name. If the features of the larval type are
unique, or all of the related species sharing the fin ray counts are accounted
for, then there will be no plus sign.
Diagnosis:
If necessary, I explain how the identification is made in a diagnosis paragraph.
The critical features for the ID are highlighted. If it is needed, the methods
I have used for larval identification, such as unique and specific morphology
or fin ray counts (U), the process of elimination (PE), DNA sequence matching
(DNA), or raising in captivity (R) are indicated at the end of the diagnosis paragraph.
Analogues: For most larval descriptions, the diagnosis paragraph is sufficient
to separate larval types, but, for some groups of species with similar-appearing
larvae, such as the gobies, I often include an additional paragraph on how that
larval type can be separated from other closely-allied larvae.
Terminology: In the text, larvae are immature fishes caught in waters above
or off the reef (usually at night), typically with adaptations to open ocean dwelling,
such as transparency or silvery coloration, extended spines and often a different
set of markings from juveniles of the species. Transitional larvae are immature
fishes caught in waters above or off the reef (also usually at night) who have
started to develop juvenile markings and morphology. Transitional recruits are
fishes associated with the reef substrate who have retained remnants of larval
markings along with their juvenile markings and morphology. They typically are
out during the day and behave as normal juveniles. Recruits are newly-settled
fishes associated with the reef substrate (let's say less than a couple of weeks
on the reef). Juveniles are young fishes on the reef who are no longer newly-settled.
Each photograph is associated
with a caption including the identification to the lowest taxonomic level possible,
the standard length (SL) in millimeters of the specimen, as well as the collection
location and collection code number. Lastly, important features that need to be
highlighted in the illustration are often included in parentheses following the
collection information. The data associated with the collection numbers (specific
location, date, etc.) can be found in my inventory
files, which are progressively being updated and posted to the web.
PERMISSIONS
My
photographs are freely available for reproduction and use in non-commercial applications.
Please e-mail me for permissions, if warranted (for my e-mail address use the
name ben followed by @coralreeffish.com). The web versions posted here are mostly
about 500 pixels wide and run from 20 to 50 kb. I have larger resolution versions,
usually about 1.5 mb jpegs, available for uses that require better resolution.
THE CARIBBEAN REEF FISH SPECIES LIST (including the Gulf
of Mexico)
Fish families
following Randall's book, but with updated, expanded, and revised species lists
including
numerous species found in non-reef habitats (if the family has reef-associated
members)
but sometimes excluding sets of deep-water species
(over ~30 m depth)
Pellona harroweri Coastal pellona
(Panama to Brazil, Pristigasteridae)
Sardinella aurita Round sardinella
Sardinella janeiro (widespread, = Sardinella brasiliensis)
FAMILY
ENGRAULIDAE
Anchoa
belizensis Belize anchovy (freshwater, Belize) Anchoa cayorum
Key anchovy Anchoa colonensis Narrow-striped anchovy (Caribbean only,
replaces A. hepsetus) Anchoa cubana (widespread) Anchoa
filifera Longfinger anchovy Anchoa hepsetus Broad-striped anchovy
(Gulf of Mexico northwards, Venezuela southwards) Anchoa lamprotaenia
Big-eye anchovy Anchoa lyolepis Shortfinger anchovy Anchoa
mitchilli Bay anchovy (Gulf of Mexico northwards) Anchoa parva
Little anchovy (Caribbean only, replaces A. mitchilli) Anchoa spinifer
Spicule anchovy (Panama to Brazil) Anchoa trinitatus Trinidad anchovy
(Gulf of Venezuela to Trinidad)
Anchovia clupeoides Zabaleta anchovy
Anchoviella blackburni (Gulf of Venezuela only) Anchoviella
elongata Elongate anchovy (Belize to Panama and Colombia) Anchoviella
perfasciata (widespread)
Cetengraulis edentulus Atlantic anchoveta
Engraulis eurystole Silver anchovy (Florida northwards and Venezuela southwards)
Lycengraulis grossidens Atlantic sabretooth anchovy (Gulf of Venezuela
eastward plus Belize)
FAMILY ANGUILLIDAE
Anguilla
rostrata Freshwater eel (pelagic larvae)
FAMILY HETERENCHELYIDAE
Pythonichthys sanguineus
FAMILY
MORINGUIDAE
Moringua
edwardsi Spaghetti eel
Neoconger mucronatus
FAMILY
CHLOPSIDAE
(excluding
several deep-water taxa from 20-500 m depth)
Catesbya pseudomuraena (Bahamas)
Chilorhinus
suensonii Seagrass eel
Kaupichthys hyoproroides False moray Kaupichthys
nuchalis Collared eel
(excluding numerous deep-water taxa from 20-500 m depth)
Ahlia egmontis
Key worm eel
Aplatophis chauliodus Tusky eel
Aprognathodon
platyventris Stripe eel
Apterichtus ansp Academy eel
Bascanichthys
bascanium Sooty eel (Gulf of Mexico and Florida north) Bascanichthys
inopinatus (Puerto Rico +?) Bascanichthys scuticaris Whip eel (Gulf
of Mexico and Florida north)
Callechelys bilinearis Twostripe snake
eel Callechelys guineensis Shorttail snake eel
Echiophus intercinctus
Spotted spoon-nose eel Echiophus punctifer Stippled spoon-nose eel
Ichthyapus
ophioneus Surf eel
Myrichthys breviceps Sharptail eel Myrichthys
ocellatus Goldspotted eel
Myrophis anterodorsalis Longfin worm
eel Myrophis platyrhynchus Broadnose worm eel Myrophis punctatus
Speckled worm eel
Ophichthus cylindroideus Ophichthus gomesii
Shrimp eel Ophichthus ophis Spotted snake eel Ophichthus puncticeps
Palespotted snake eel Ophichthus rex (Gulf of Mexico)
Quassiremus
ascensionis Black-spotted snake eel
FAMILY
CONGRIDAE
(excluding
numerous deep-water taxa from 20-500 m depth)
Conger esculentus
Grey conger Conger oceanicus American conger (Gulf of Mexico, north)
FAMILY
OPHIDIIDAE, SUBFAMILIES BROTULINAE AND NEOBYTHITINAE
(excluding numerous deep-water
taxa from 20-8000 m depth)
Brotula barbata
Petrotyx sanguineus
FAMILY
OPHIDIIDAE, SUBFAMILY OPHIDIINAE
(excluding
numerous deep-water taxa from 20-500 m depth)
Lepophidium brevivarbe
Ophidion beani (Florida and Gulf of Mexico) Ophidion grayi
(Florida and Gulf of Mexico) Ophidion holbrookii (= Ophidion holbrooki) Ophidion
josephi (Florida and Gulf of Mexico) Ophidion lagochila Ophidion
marginatum Ophidion nocomis (Antilles) Ophidion selenops
(Florida and Gulf of Mexico) Ophidion welshi (Florida and Gulf of Mexico,
incl. Ophidion marginatum?)
Cynoscion acoupa (Panama
to Argentina) Cynoscion arenarius (Florida and Gulf of Mexico) Cynoscion
jamaicensis Cynoscion leiarchus (Nicaragua to Brazil) Cynoscion
microlepidotus (Venezuela to Brazil) Cynoscion nebulosus Spotted
weakfish (Florida and Gulf of Mexico) Cynoscion nothus Silver seatrout
(Florida and Gulf of Mexico) Cynoscion similis (S. Caribbean) Cynoscion
virescens (Nicaragua to Brazil)
Larimus breviceps Shorthead drum Larimus
fasciatus (Florida and Gulf of Mexico)
Leiostomus xanthurus
Spot (Florida and Gulf of Mexico)
Lonchurus elegans (S. Caribbean)
Lonchurus lanceolatus (S. Caribbean)
Macrodon ancylodon
King weakfish (SE Caribbean)
Menticirrhus americanus Southern kingfish
Menticirrhus littoralis Menticirrhus saxatilis (Florida and
Gulf of Mexico)
Micropogonias furnieri Micropogonias undulatus
Atlantic croaker (Florida and Gulf of Mexico)
Nebris microps (Colombia
to Brazil)
Odontoscion dentex Reef croaker
Ophioscion costaricensis
(Costa Rica and Suriname) Ophioscion panamensis (Belize to Panama) Ophioscion
punctatissimus (Panama to Brazil, and Puerto Rico)
Eugerres brasilianus (Belize, Cuba south to Brazil?) Eugerres
mexicanus Mexican mojarra (freshwater, Mexico and Guatemala, Rio Usumacinta) Eugerres
plumieri Striped mojarra (Florida, Gulf of Mexico to Cuba and Panama?)
Hypleurochilus bermudensis (Bermuda,
Bahamas to Florida) Hypleurochilus caudovittatus (Florida) Hypleurochilus
geminatus (Florida north) Hypleurochilus multifilis (N. Gulf of
Mexico) Hypleurochilus pseudoaequipinnis Oyster blenny (previously part
of Hypleurochilus aequipinnis) Hypleurochilus
springeri Orangespotted blenny
Hypsoblennius brevipinnis
(Pacific species, invading Panama Canal) Hypsoblennius exstochilus (N.
Caribbean islands) Hypsoblennius hentz (often Hypsoblennius hentzi,
continental, US to Yucatan) Hypsoblennius
invemar Hypsoblennius ionthas (N. Gulf of Mexico, north)
Lupinoblennius
nicholsi (N. Gulf of Mexico) Lupinoblennius vinctus Mangrove blenny
(= Lupinoblennius dispar)
Fortunately,
in most reef fishes the larval markings are quite different from the juvenile
markings. Larval melanophores are typically large, often stellate, individual
black spots that extend below the skin surface. These markings are replaced during
the settlement transition by metamorphic melanophores in the patterns shown by
juveniles on the reef. These arrays of additional melanophores (and sometimes
leukophores and iridophores), are usually much smaller and right at the skin surface.
In addition, they are typically numerous and in dense patches that often begin
on the head and develop posteriorly following the pattern of the juvenile markings
of the species. This Labrisomus haitiensis transitional larva shows the
prominent three larval melanophores surrounded by the patches of fine metamorphic
melanophores. In many species, this transition can take days and often the larval
markings coexist with the developing juvenile patterns. These metamorphic melanophores
are invaluable for identifications.
