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Group 1: six-spined shortfin gobies 1
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Group 2: six-spined shortfin gobies 2
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Group 3: seven-spined shortfin gobies
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Group 4: longfin gobies
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allied family Ptereleotridae
allied family Eleotridae
allied family Microdesmidae
Group 5: Gobies with divided pelvic fins

Psilotris, Varicus, Chriolepis, Pycnomma, Gobulus, (and Robinsichthys)

 
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 the similar appearing (but not gobioids) Ptereleotridae, which have pelvic fins that are separate, even at the base.
  psilotris amblyrhynchus (goby reef fish larvae)
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, where the pelvic-fin morphology is, unfortunately, an important species-level character. larval gobies, fused pelvic fins
goby 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 (C. alloides, C. lipernes, C. personatus, and C. hyalinus). It is 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, Varicus, Chriolepis, and the individual species Pycnomma roosevelti and very deep 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 species 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 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.
 
In the genus Psilotris, P. batrachodes has the fewest fin rays with modal D-9 A-7 Pect 16; P. alepis has D-9-10-11 A-8-9 Pect 15, P. celsa (originally "Psilotris celsus") has D-9-11 A-9-10-11 Pect 16-17-19, P. boehlkei has D-10-11 A-10 Pect 16-18, and P. kaufmani has D-11 A-10-11 Pect 16-18-19. P. amblyrhynchus has D-11-12 A-10-11 Pect 17-19. Psilotris are scaleless.
 
Pycnomma roosevelti has a similar general appearance and 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 (and Pect 17) but is from a fused-fin genus and has only partially-divided pelvic fins and a small pelvic frenum and a very different body shape.)
 
Chriolepis and Varicus are rare, obscure, and mostly deep-water gobies that typically have divided and long pelvic fins and large eyes. The species comprise Chriolepis fisheri (the only relatively shallow water species (can be found in sand tilefish mounds); D-11-12 A-10-11 Pect 17-18, with two large spiny basicaudal scales), Chriolepis benthonis (over 150m, Gulf of Mexico, D-9 A-8 Pect 16), Chriolepis bilix (described in 2013, over 60m, widespread, D-12 A-11-12 Pect 19-20), and Chriolepis vespa (deep, Gulf of Mexico, D-10 A-7-9 Pect 15-17). The related genus Varicus differs by having unbranched pelvic-fin rays and comprises Varicus bucca (very deep-water, D-9-10 A-8 Pect 16-19), Varicus marilynae (deep-water, Florida, 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 14-15). A profoundly deep-water goby, Robinsichthys arrowsmithensis, has D-VII,11 A-11 and is distinctive with 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.
Psilotris batrachodes
 
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 (occ.15), with 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 somewhat thick, long, and narrow with a small round eye and a terminal mouth. Head relatively broad and flattened. Pectoral fins long, dorsal and anal-fin bases short and placed well back on the body, caudal peduncle relatively short and narrowing. Internal melanophores around the sacculus and on the dorsal surface of the swim bladder as well as around the gut near the vent. There is a large melanophore on the ventral midline just after the last anal-fin ray. Many individuals have a smaller matching melanophore on the dorsal midline just after the last dorsal-fin ray. Many individuals have a bubblewrap-like appearance to the skin.
Psilotris batrachodes larva
6.0 mm SL
San Blas, Panama, SB84-522
 
psilotris batrachodes
  goby reef fish larvae
Psilotris batrachodes adult
13.3 mm SL
Saba Bank, Lesser Antilles
Photo by JT Williams
psilotris batrachodes
Psilotris alepis
 
Diagnosis: A modal fin-ray count of D-VII,10 A-9 and Pect 14-15 and divided pelvic fins indicates Psilotris alepis (typically one fewer anal-fin ray than second-dorsal-fin rays). The only Psilotris species with fewer than 16 pectoral-fin rays are P. batrachodes and P. alepis. P. batrachodes larvae have 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 and Varicus). (PE) G19b
Analogues: (post-anal fin single melanophore, small: <7 mm SL) Among the taxa with divided pelvic fins and the single melanophore behind the anal fin, several types have small larvae. Larval Psilotris alepis are separated from larval Pycnomma roosevelti by having no dorsal melanophores, and from larval Gobulus myersi by having well-separated and longer pelvic fins, a long pectoral fin reaching almost to the vent, a wider caudal peduncle and no abdominal midline melanophores. Larvae of Psilotris batrachodes are similar and can be distinguished by the lower fin-ray counts (especially the short anal fin) and a narrower caudal peduncle.
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
 
  goby reef fish larvae
  goby reef fish larvae
  goby reef fish larvae
  goby reef fish larvae
  goby reef fish larvae
Psilotris boehlkei
 
Diagnosis: A modal fin-ray count of D-VII,10-11 (usually 11) A-10 Pect 16-18 and divided pelvic fins indicates Psilotris boehlkei or P. celsa or Chriolepis fisheri (typically one fewer anal-fin ray than second-dorsal-fin rays). Psilotris kaufmani can overlap the counts, but usually has 11 anal-fin elements. C. fisheri can be distinguished by having two basicaudal scales. Unfortunately the 11/10 median fin ray count is very common among gobies and the state of the pelvic fins is therefore a critical feature for diagnosis, but often difficult to observe. Numerous Gobiosoma and Tigrigobius gobies overlap the counts, but have fused pelvic fins- their overall morphology is often slightly different, i.e. less likely to have a wide caudal peduncle and rounded caudal fin and have a less flattened head, but it is subtle. Gobies with six dorsal spines and fused pelvics can share the fin-ray count (and can have very similar adult markings), including the sand gobies of Coryphopterus, however they usually have equal numbers of dorsal and anal fin rays and characteristically have relatively narrow caudal penduncles and do not have the obvious rounded caudal fin.
Description: Larvae not identified.
Psilotris boehlkei adult
26.5 mm SL
Saba Bank, Lesser Antilles
Photo by JT Williams
psilotris boehlkei
Psilotris amblyrhynchus
 
Diagnosis: Mostly-divided pelvic fins and the modal fin-ray count of D-VII,12 A-11 Pect 17-19 indicates Psilotris amblyrhynchus and overlaps Gobulus myersi and Chriolepis fisheri (the latter has fully divided pelvic fins and prominent modified basicaudal scales). This larval type matches the species description for P. amblyrhynchus.
Analogues: (post-anal fin single 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 12/11 with a range of 11-12/9-11 vs. 12-14/11-13). Other members of the group are much smaller: Psilotris, Gobulus myersi, and Pycnomma roosevelti with divided pelvic fins and typically other distinctive melanophores, and, with fused pelvic fins, some Gobiosoma and Elacatinus, along with Evermannichthys (the latter also have a sharply-pointed snout and spiny caudal peduncle scales).
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. Many individuals have a bubblewrap-like appearance to the skin.
Psilotris amblyrhynchus larva
12.1 mm SL
Banco Chinchorro, Mexico, coll. D. Jones
 
goby reef fish larvae
  goby reef fish larvae
  separate pelvic fins
  goby identification
Pycnomma roosevelti
 
Diagnosis: Modal fin-ray counts of D-VII,10 A-9 and Pect 16 and divided pelvic fins indicates Pycnomma roosevelti. The appearance and fin-ray counts are quite similar to the Psilotris, but a strong mode at this count of fin elements excludes the Psilotris species. P. alepis larvae have fewer pectoral-fin rays and lack the dorsal melanophore. Psilotris boehlki and P. celsa both have a strong modal anal-fin-ray count of 10 and are therefore excluded. An adult Pycnomma roosevelti from the Saba Bank matches the transitional larva 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. The hunched-over appearance, with the head placement mostly below the lateral midline of the body, occurs in both the larvae and adult from Saba. In addition, the larval melanophores on the body at the end of the dorsal and anal fins match markings at the same location on the Saba specimen. (PE) G19a
Analogues: (post-anal fin single melanophore, small: <7 mm SL) Among the taxa with divided pelvic fins and the single melanophore behind the anal fin, several types have small larvae. Larvae of Psilotris batrachodes are most similar and often have a post-dorsal fin spot as well (although it is typically smaller than the ventral spot). When the dorsal melanophore is present, Psilotris batrachodes can be distinguished by the lower fin-ray counts (especially the short anal fin) and a narrower caudal peduncle. Psilotris alepis larvae have only a ventral spot and Gobulus myersi have abdominal ventral midline spots.
Description: Body somewhat thick, long, and narrow with a relatively small round eye and a terminal mouth. Larvae are usually hunched-over, with the head mostly bent 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. Internal melanophores around the sacculus and on the dorsal surface of the swim bladder. A surface melanophore around the gut near the vent and large solitary melanophores on the caudal peduncle placed just behind the last dorsal and anal-fin rays. Transitional larvae become more flattened and 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
6.0 mm SL
Yucatan, Mexico, 240306
coll. by Lourdes Vasquez et al.
pycnomma roosevelti (goby reef fish larvae)
Pycnomma roosevelti larvae
6.0 mm SL
Yucatan, Mexico, 240306
coll. by Lourdes Vasquez et al.
divided pelvic fins
   
Pycnomma roosevelti larva
6.0 mm SL
divided pelvic fins
Yucatan, Mexico, 240306
coll. by Lourdes Vasquez et al.
larval melanophores
Pycnomma roosevelti transitional larva
5.5 mm SL
San Blas, Panama, SB84-624a
 
goby panama
Pycnomma roosevelti adult
14.6 mm SL
Saba Bank, Lesser Antilles
Photo by JT Williams
goby saba
   
   
Gobulus myersi
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 species 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) rather than the other gobies with these fin-ray counts and fully-fused pelvic fins (i.e. some Gobiosoma and Elacatinus). The fin-ray count of this larval type borders the range but does not match Psilotris (too high for P. alepis; modal pectoral-fin rays too low for P. boehlkei and P. celsa). 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 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 species 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 can share 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 (goby reef fish larvae)
  early life history
  ID larvae
Gobulus myersi larva
5.5 mm SL
seven midline abdominal melanophores
San Blas, Panama, SB86-1103
 
coral reef fish
  larval fish morphology
Gobulus myersi larva
5.7 mm SL
slightly narrowed vertical eye
San Blas, Panama, SB87-219
 
early stages
Gobulus myersi larvae
5.2 and 5.5 mm SL
San Blas, Panama, SB86-503
 
development of goby larvae
Gobulus myersi larva
5.5 mm SL
halfway fused pelvic fins
and short pectoral fins
San Blas, Panama, SB86-503
 
goby pelvic fin
  larval morphology
Gobulus myersi larva
5.8 mm SL
D-VII,12 A-11 Pect 15
San Blas, Panama, SB86-503
 
key to larval gobies
Gobulus myersi transitional larva
6.0 mm SL
San Blas, Panama, SB86-501
 
stages of goby larvae
  larval melanophores
  paleback goby
Gobulus myersi transitional larva
6.0 mm SL
leukophores on dorsal side
San Blas, Panama, SB87-224
 
larval structure
Gobulus myersi transitional larvae
6.0 and earlier-stage, 4.9 mm SL
San Blas, Panama, SB87-224
 
paleback goby larval transition
Chriolepis fisheri
 
Diagnosis: Modal fin-ray counts of D-VII,11-12 A-10-11 and Pect 17-18 and divided pelvic fins indicates Chriolepis fisheri. Only this species has two prominent spiny basicaudal scales, and they are present on late-stage larvae.
Analogues: (post-anal fin single melanophore, small: <7 mm SL)
Description:
 
 
 
 
chriolepis fisheri(goby reef fish larvae)
 
 
 
 
chriolepis fisheri
   
 
 
 
 
 
chriolepis fisheri
 
chriolepis fisheri
 
 
 
 
chriolepis fisheri
   
   
Chriolepis/Psilotris sp. 23 (?)
 

Diagnosis: An individual larva with a robust body and large eye and 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, with this fin-ray count, it is likely that the pelvic fins in this larval type are divided, since fused-pelvic-fin gobies rarely have as few as 10 second-dorsal-fin elements: only Barbulifer and Gobiosoma grosvenori have 10, but both have the typical one-fewer-anal than dorsal-fin elements. In addition, Barbulifer larvae are morphologically quite different and larval Gobiosoma are lightly-marked and smaller (note that rare individuals of Gobiosoma spes and G. yucatanum would also overlap the fin-ray count of this larva, but neither would resemble this larva).

Among the divided-pelvic-fin species, a number have overlapping fin-ray counts to this larval type, including Psilotris celsa, P. boehlkei, P. kaufmani, and Pycnomma roosevelti. Species of Chriolepis have similar (but not the same) fin-ray counts. Larvae of P. roosevelti are quite different and have small eyes and a flattened head. Psilotris boehlkei do not appear similar: the Saba adult is relatively lightly marked with a pale body marked only by short midline internal linear melanophores, melanophores in a patch under the lower jaw, a large patch below the eye, a patch on the upper pectoral-fin base and stripes back from the upper eye (notably, these markings are similar to the common Coryphopterus sand gobies). On the Saba fish, there are two stripes across the spinous dorsal fin, black edging to the soft dorsal-fin membranes and around the caudal fin and mostly dark membranes on the anal fin. Notably there are no obvious ventral midline melanophores along the anal fin and caudal peduncle which are prominent on this larval type. Psilotris kaufmani and Psilotris celsa cannot be excluded as possible candidates, and the former shares the large eye and bulky body of this larva. Chriolepis spp. cannot be ruled out, but the larva differs from larval Chriolepis fisheri in appearance and fin-ray counts and lacks the spiny basicaudal scales. (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 larvae. In addition, this larval type has seven first-dorsal-fin spines vs. six in Bathygobius.

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/Psilotris sp. larva
7.4 mm SL
San Blas, Panama, SB81-196
 
chriolepis fisheri (larval reef gobies)
  chriolepis fisheri
  caribbean goby larvae
  western atlantic gobies
 
 
 

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