Key to the eastern Pacific genera of Gobiids
From northern Mexico to Chile
by J. Van Tassell
updated 12 Dec 2002

1a

Dorsal fins connected at least 1/4 distance of D2 spine; body elongate; eyes very
small, on sides of head; dorsal and anal fins broadly joined to the caudal fin ...... 2

 

 

1b

Spinous and ray portions of dorsal fin not connected, or if connected by
not more than 1/4 the distance from base to distal margin of the first
element in D2.................................................................................................. 3

2a

Spinous and ray portions completely connected forming a single fin, D1 with 6
spines; eyes small, not extending above profile of head; interorbital space greater
than 4 times eye diameter; D2 - 16; anal - 16; 2-3 rows of teeth in each jaw;
inhabits muddy burrows in tidal streams ............................. Gobioides peruanus


2b

Dorsal fins connected on lower 1/4 of first element of D2, D1 VII; outer teeth very long, widely spaced; top jaw not reaching center of eye .......................................... Akko

3a First dorsal fin with 6 or fewer spines ..........................................................................4
3b First dorsal fin with 7 or more spines........................................................................ 15
4a First dorsal fin with 4-5 spines ......................................................................................5
4b First dorsal fin with 6 spines...........................................................................................8
5a

First dorsal fin with 4 spines, rarely 5 or 6; flexible dermal flap present on
shoulder girdle; minute embedded scales, visible only with a microscope, or
scaleless .................................................................................... Evermannia

5b

First dorsal fin with 5 spines; shoulder girdle with dermal flaps or papillae (A);
scales present or absent .............................................................................................6

A
6a

Maxilla extending only to under middle of eye (A); conspicuous spot on opercle
present or absent.......................................................................................... Ilypnus

A
6b

Maxilla extending well past posterior of eye; no conspicuous spot on opercle ..... 7

A
7a

Pelvic fins insert in front of pectoral fin base; head with very low keel or ridge along
the top; ........................................................................................................ Quietula

7b Pelvic fins insert behind pectoral fin base; no keel or ridge on top of
head;...............................................................................................Clevelander ios
8a

Small gobies (less than 2.5 cm) with head and body more or less laterally
compressed; body slender and not expanded dorso-ventrally; head canals
without pores; thin vertical bars on body; predorsal scales lacking; ...Lythrypnus

8b

Small(A) to large gobies(B) with head and body not laterally compressed, or if
compressed, body with dorso-ventral expansion and fleshy crest on head(C);
head canals and pores present; head and body with or without vertical bars;
predorsal scales present or absent ............................................................................9

A
B
C
9a

Pectoral fin with first few rays almost completely free from membrane; head
and body with scales......................................................................Bathygobius

9b

Pectoral fin with all rays enclosed within the membrane, or only the first dorsal ray
¼ to ½ free or with only the tips of rays projecting from membrane; body scaled,
head with or without scales........................................................................................... 10

10a

Body laterally compressed and head with dermal ridge; ......................Lophogobius

10b Body not laterally compressed, no dermal ridge on head ....................................... 11
11a

Mouth very large, extending to pectoral fin base or beyond; 80-100 scales
in lateral series ...........................................................................................Gillichthys

11b

Mouth not large, ending before or just posterior to eye; less than
80 scales in lateral series ........................................................................................... 12

A
12a

Body not elongate; caudal fin rounded (A); .............................................................. 13

A
12b

Body elongate; caudal fin elliptical (A) or lanceolate (B).......................................... 14

A
B
13a

Head and body completely scaled; teeth forked at tips(A); head profile steeply
rounded(B) .................................................................................... Evorthodus minutus

A
B
13b

Body scaled only to anterior of D1, no scales on head or opercle; teeth pointed(A),
not forked at tip; head profile straight between eye and upper jaw (B)
................ .............................................................................Coryphopterus urospilus

A
B
14a

Ocular-scapular canal with two pores; ..................................................Ctenogobius

14b

Ocular-scapular canal with four pores; ..................................................Gobionellus

15a First dorsal with 8 spines; cephalic canal separate between eyes; pore C absent;
canals separate between orbits; pelvic fin disk shaped; tongue bilobed; body
naked; D2 - 15-16; anal - 12-14; upper jaw with 5 rows of teeth, outer row large
and widely spaced, lower jaw 4 rows, outer with 5 enlarged teeth on each side
........................................ .............................................................. Ophiogobius jensi
15b First dorsal with 7 spines; a single cephalic canal between eyes; pore C present
or absent ..................................................................................................................... 16
16a

Ventral surface of lower jaw with three or more barbels; head without scales
.................... .................................................................................................. Barbulifer

16b

Ventral surface of lower jaw without barbels(A) or if present only a pair located at the
anterior median symphysis(B); head with or without scales......................................17

A
 
B
17a

Pelvic fins completely separated (A), no frenum connecting the spines and no
membrane connecting the 5th rays(Fig A);............................................................... 18

A
17b

Pelvic fin with a frenum connecting the spines and the 5th rays connected at
least in part by a membrane(A)............................................................................. 21

A
18a Front nostril longer than rear nostril ....................................................................... 19
18b Rear nostril longer than front nostril ....................................................................... 20
19a Head without pores......................................................................... Chriolepis
19b Head with pores; body with ctenoid scales; scales at the base of the caudal
fin with large ctenii; posterior nostril much smaller than the anterior
nostril .............................................................................. Pycnomma semisquamatum
20a

Scales on caudal peduncle cycloid; no anterior pelvic frenum; body with
distinct vertical narrow white bands(10-15) from pectoral base to caudal
fin ............................................................................................... Gymneleotris seminudus

20b

Scales on caudal peduncle ctenoid; small anterior pelvic frenum; color of body pale brown with white spots ........................................................................ Eleotrica cableae

21a

Head without pores; pelvic fin lacking an anterior frenum but with the 5th rays connected by a membrane; ........................................................................... Gobulus

21b

Head with pores; pelvic fins connected with an anterior frenum between the spines and the 5th rays also united by a membrane ..........................................................22

A
22a

Head, nape, and breast with scales; head somewhat laterally compressed; body color generally a uniform grey-brown, occasionally with faint vertical bars along midline; ......................................................................................................... Bollmannia

22b Head and nape without scales; ..................................................................................23
23a

Tongue bilobed (Fig A); cephalic head pore C lacking ........................................... 24

23b Tongue rounded or truncate, not bilobed (Fig B above); cephalic head pore C generally present..........................................................................................................26
24a

Body without scales; a prominent dark, crescent bar occurs on the outer base of the pectoral fin; body with narrow, vertical cream colored bands; head distinctly depressed; tongue bilobed; D2 - 12-13; anal - 11-13; gill rakers 9-12(8-14) ...................................................................................................................Aruma histrio

24b Body with scales, at least on the posterior half; ...................................................... 25
25a

Second dorsal fin with 15 or more elements; Eyes not greatly reduced in size; interorbital equal to or less than eye diameter; head and body somewhat laterally compressed; outer row of teeth in jaws not exposed.............................. Microgobius

25b

Second dorsal fin with 11-14 elements............................................................Parrella

 
26a

Scales on body small and may be somewhat embedded, 40-60 in lateral series; barbels present, at least, on lower median lip and by anterior nostril ..........Enypnias

26b Scales on body larger and less than 36 in laterial series or lacking entirely; barbels present or absent; ............................................................................................... 27
27a

Scales on body reduced to only 2 basicaudal scales(A) or lacking entirely; body with colored vertical bands or blotches(B) ...................................................... Elacatinus

A
B
27b

Scales on body at least on caudal peduncle, not extending along dorsum
further than anterior of D1; body generally a drab brown with blotches or
bands of similar colors ............................................................................................. 28

 
28a

Scales on body extending to first or second dorsal spine, along dorsal midline(A); pore G present in oculoscapular canal(B); snout pointed; D2- 11-12; anal - 10-11; scale in lateral series 26-30; head pores B',C(s),D,E,F,G,H' and K',L '; preopercle pores M',N,O' ............................................................................ Aboma etheostoma(C)

A
B
C
28b

Scales on midline of body extending to middle of D1 at most (A); pore G absent;
snout rounded(B) ..........................................................................................Gobiosoma

A
B

 

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