Freshwater Fishes of Iran


Keys - Genera and Species

Revised:   23 August 2007

Families     Genera and Species     Regional Ichthyofaunas

The following keys identify species in the more speciose families and genera. Some keys identify both genera and species, others have separate keys for genera and for species within genera. Some species are similar and have overlapping meristic characters. Distribution is often an additional guide to identity. It should be noted that some species are known to have been introduced to basins outside their natural range, and the possibility exists that other species may also have been translocated.

The Gobiidae key is divided by geographical area - Caspian Sea and tributary rivers and the rivers draining to the Persian Gulf and Sea of Oman.

Keys are arranged alphabetically by family and by genera within families.

Key to the genera and species of Acipenseridae

 

Underside of heads of H. huso, A. nudiventris, A. gueldenstaedtii, and A. stellatus. Note that A. persicus is very similar to A. gueldenstaedtii.

1. Mouth a large crescent; gill membranes joined to form a free fold over the isthmus = Huso huso
    Mouth small and transverse; gill membranes attached to isthmus --->

2. Lower lip continuous, not split in middle; more than 48 lateral scutes, usually 55 or more; barbels fimbriate = Acipenser nudiventris
   
Lower lip interrupted in the middle; less than 51 lateral scutes (usually less than 45 in Iranian waters); barbels not fimbriate ---> 3

3. Snout long and narrow (more than 61% of head length); barbels closer to mouth than tip of snout = Acipenser stellatus
    Snout shorter and broader (less than 60% of head length); barbels nearer to tip of snout than mouth ---> 4

4. Back golden-brown, belly yellowish-white; average body depth 12-14% of total length = Acipenser gueldenstaedtii
    Back greyish-blue, belly white; average body depth 16.8% of total length = Acipenser persicus

Key to the species of Balitoridae

?

1. Body without pigment, pinkish from blood visible through skin; eyes absent or reduced to spots = Nemacheilus smithi
    Body pigmented; eyes small but distinctive ---> 2

2. Well-developed crest on back behind dorsal fin ---> 3
    No well-developed crest ---> 6

3. Branched dorsal fin rays modally 8 = Nemacheilus cristatus
    Branched dorsal fin rays modally 7 ---> 4

4. Sistan basin;  = Nemacheilus rhadinaeus
    Not in Sistan basin ---> 5

5. Body covered with scales; up to 20 cm in length = Nemacheilus longicaudus
    Body without scales or scales restricted to caudal peduncle; up to 10 cm in length = Nemacheilus malapterurus

6. Flank pigment flowing together to form a stripe = Nemacheilus kermanshahensis
    Flank pigment spots or bars but no central stripe ---> 3

Nemacheilus angorae

Nemacheilus bampurensis

Nemacheilus bergianus

Nemacheilus brandti

Nemacheilus frenatus

Nemacheilus kessleri

Nemacheilus persus

Nemacheilus sargadensis

Nemacheilus stoliczkai

Nemacheilus cf. tigris

Key to the genera and species of Centrarchidae

These two exotic species may not have reproducing populations in Iran.

1. Lateral line scales small, 58-81; body rounded in cross section and elongate, maximum body depth 2.5-5.0 (usually 3.0 or more) times in body length from snout tip to end of scales =  Micropterus salmoides
   
Lateral line scales large, 35-50; body compressed in cross section and deep, maximum body depth 1.7-3.0 (usually 2.5 or less) times in body length from snout tip to end of scales = Lepomis macrochirus

Key to the genera and species of Clupeidae

Caspian Sea species have numerous nominal subspecies and keys to these may be found in Berg (1948-1949) and Svetovidov (1952).

1. Upper jaw without a median notch, rounded when viewed from in front; last two anal fin rays enlarged; lower jaw articulation with skull below or anterior to posterior eye margin; Caspian Sea species ---> 2
    Upper jaw with a median notch; last two anal fin rays not enlarged; lower jaw articulation with skull behind posterior eye margin ---> 4

2. Pectoral fins pointed at tips; head short and wide (interorbital width 16% or more of head length) ---> 3
    Pectoral fins rounded at tips; head large and narrow (interorbital width 15.5% or less of head length) = Clupeonella grimmi

3. Body and belly compressed (body depth about 21-27% of standard length); keeled belly scales evident = Clupeonella cultriventris
    Body cylindrical and belly rounded (body depth 16-19% of standard length); keeled belly scales weakly developed = Clupeonella engrauliformis

4. Branched pelvic fin rays 8; upper gill rakers overlap lower gill rakers at angle of first arch; Caspian Sea species ---> 5
    Branched pelvic fin rays 7; upper gill rakers not overlapping lower gill rakers at angle of first arch; marine, entering rivers of southern Iran = Tenualosa ilisha

5. Body deep and compressed; head large and deep, wedge-shaped in anterior view; caudal peduncle short; pectoral fins long ---> 6
    Body not deep and not compressed; head not large and deep, not wedge-shaped in anterior view; caudal peduncle not short; pectoral fins short ---> 8

6. Gill rakers on first arch 60 or more, thin and long, much longer than gill filaments; teeth weakly developed = Alosa caspia
    Gill rakers on first arch 45 or less, shorter, equal to or somewhat longer than gill filaments; teeth well developed ---> 7

7. Upper and lower profiles of head straight; lower jaw protruding and its upper edge straight = Alosa saposchnikowii
    Upper and lower profiles of head rounded; jaws equal in length and lower jaw has a crescentic upper edge = Alosa sphaerocephala

8. Gill rakers 47 or less, thick and coarse = Alosa braschnikowii
    Gill rakers 59 or more, may be thin and long but can be coarse and short = Alosa pontica

Key to the genera and species of Cobitidae

  see Berg

Key to the genera and species of Cyprinidae

The cyprinid family is the most speciose in Iranian fresh waters. Members of the family are more easily identified first to genus and then to species. Keys are then shorter and less liable to error in use. Additional characters can be listed under each genus or species which are not unique nor readily incorporated into keys but which in combination help to identify the genus or species. These additional characters are given in brackets. Monotypic genera key out to species in the generic key.

?Add petroleuciscus

1.  Branchiostegal membranes not attached to isthmus; gill rakers fused together; eyes low on side of head, below midline; suprabranchial organ present =     Hypophthalmichthys
    Branchiostegal membranes attached to isthmus; gill rakers not fused; eyes at or above midline of head; suprabranchial organ absent ---> 2

2. Serrated stiffened ray (spine-like) in the dorsal and anal fins; dorsal fin elongate (? rays or more, usually ?); anal fin origin below dorsal fin ---> 3
    No serrated stiffened ray (spine-like) in the anal fin; dorsal fin short to moderately elongate (?-? rays, usually ?); anal fin origin behind dorsal fin end ---> 4

3. Barbels absent; pharyngeal teeth in one row = Carassius
    Barbels present (two pairs); pharyngeal teeth in three rows = Cyprinus

4. Eyes absent; body pink through lack of pigment; no scales = Iranocypris typhlops
    Eyes present; body pigmented; scales present, sometimes restricted to anal area ---> 5

5. Anus and anal fin base sheathed by markedly enlarged scales ---> 6
    Anus and anal fin base not sheathed by markedly enlarged scales ---> 8

6. Branched anal fin rays 5; scales mostly absent; pharyngeal teeth in two rows =  Schizopygopsis
   
Branched anal fin rays 6; scales present; pharyngeal teeth in three rows =  

Schizothorax
Schizocypris
 

7. 

8.  An adhesive disc on the underside of the head = Garra
    No adhesive disc

 

Pelecus

mouth structure Pseudorasbora

10.  naked ventral keel Abramis  Alburnoides Alburnus  Blicca  Chalcalburnus  Vimba  (also put alburnoides, alburnus and chalcalburnus in another couplet)

Barbels present ---> x
Barbels absent

 

x. Spine in dorsal fin ---> h
    No spine in dorsal fin ---> c

h. Spine smooth; mouth not sector-shaped = Barbus (partim)
    Spine with teeth; mouth sector-shaped (u-shaped in young) ---> i

i. Branched anal fin rays 6, dorsal fin branched rays 10 or more; lateral line scales ? = Cyprinion
   Branched anal fin rays 5; dorsal fin branched rays 9 or less; lateral line scales ? = Capoeta

c. Scales small, more than ?100 in lateral line = Tinca tinca
    Scales larger, less than ? in lateral line ---> q

q. Anal fin branched rays 13 or more = Barilius mesopotamicus
   
Anal fin branched rays less than 13 ---> t

t. Dorsal fin branched rays 7; pharyngeal teeth in two rows = Gobio
    Dorsal fin branched rays 8; pharyngeal teeth in one row ---> s

s. Lateral line complete = Crossocheilus
    Lateral line incomplete = Hemigrammocapoeta

Acanthalburnus

Acanthobrama

Aspidoparia

Aspius

Barbus

Barilius

Capoeta

Chondrostoma

Crossocheilus

Ctenopharyngodon

Cyprinion

Garra

Gobio

Hemiculter

Hemigrammocapoeta

Leucaspius

Leuciscus

Petroleuciscus

Pimephales

Rhodeus

Rutilus

Scardinius

Tinca

 

 

Acanthobrama marmid

Alburnoides bipunctatus

Aspidoparia morar

Barilius mesopotamicus

Blicca bjoerkna

Crossocheilus latius

E Ctenopharyngodon idella

Cyprinus carpio

E Hemiculter leucisculus

Hemigrammocapoeta elegans

Leucaspius delineatus

Pelecus cultratus

E Pimephales promelas

E Pseudorasbora parva

Rhodeus sericeus

Scardinius erythrophthalmus

Schizocypris altidorsalis

Schizopygopsis stoliczkai

Tinca tinca

Vimba vimba

Key to the Species of Abramis

1. Branched anal fin rays 22-30 = Abramis brama
    Branched anal fin rays 31-44, mostly 34 or more = Abramis sapa

Key to the Species of Acanthalburnus

1. Anal fin branched rays 13-19; lateral line scales 60-85; Caspian Sea = Acanthalburnus microlepis
    Anal fin branched rays 10-13; lateral line scales 50-68; Lake Orumiyeh = Acanthalburnus urmianus

Key to the Species of Alburnus

add Chalcalburnus

Key to the Species of Chalcalburnus

1.  Total gill rakers 18-25 (usually 19 or more); branched anal fin rays 12-19 (usually 13 or more); peritoneum light brown; Caspian Sea basin = Chalcalburnus chalcoides
   
Total gill rakers 11-18 (usually 16 or less); branched anal fin rays 9-14 (usually 13 or less); peritoneum brown to black; outside Caspian sea basin ---> 2

2. Lateral line scales 46-63 (usually 58 or less); Lake Orumiyeh basin = Chalcalburnus atropatenae
    Lateral line scales 58-89 (usually ? or more ? see data sheets); Tigris, Kor and Gulf drainages = Chalcalburnus mossulensis

 

1. Dorsal fin branched rays modally 8 (range usually 7-9); lateral line scales usually 39-50 (maximum range 36-55); anal fin branched rays usually 12-16 (maximum range 10-21); no strong mid-flank stripe = Alburnus alburnus
    Dorsal fin branched rays modally 7 (range usually 6-8); lateral line scales usually 50-57 (maximum range 46-64); anal fin branched rays usually 10-12 (maximum range 9-13); a strong mid-flank stripe = Alburnus filippi

Key to the Species of *Aspius

1. Lateral line scales 62-105; anal fin branched rays 11-15, usually 12; total gill rakers 8-11; total vertebrae 50-51; Caspian Sea basin = Aspius aspius
    Lateral line scales 91-110; anal fin branched rays 10-13, usually 11?; gill rakers 11-14; total vertebrae 51-53; Tigris River basin = Aspius vorax  

* The distinction of these two species has not been examined recently and characters overlap, sample sizes for gill rakers and scales above in particular being very small. However they are found in separate basins.

Key to the Species of Barbus

?Teeth counts, barbel and lip shapes, scales above l.l. etc for further distinction

1. Barbels absent [scales large, 29-35 in lateral line; body compressed; Tigris River basin; dorsal fin spine smooth, without denticulations] = Barbus sharpeyi
    Barbels present ---> 2

2. Branched dorsal fin rays 9-11, usually 10 (9 = 7.5%, 10 = 86.9%, 11 = 5.6% for 160 fish); anal fin branched rays with strong mode at 6 (99%); lateral line scales large, 38 or less and mostly 35 or less; body compressed ---> 3
    Branched dorsal fin rays with strong mode at 8 (97.5%, only one fish with 9 rays out of 161 fish), 7 in one species; anal fin branched rays with strong mode at 5 (100%); lateral line scales medium to small, rarely large, 34-103, mostly 42 or more; body rounded in cross section ---> 5

3. Mouth terminal, no rounded median lobe on lower lip, usually 2 barbels (third or fourth barbels if present minute); Tigris River basin; Persian Gulf tributaries [scales 23-31; dorsal fin spine smooth, without denticulations] = Barbus luteus
    Mouth subterminal, rounded median lobe on lower lip, 4 barbels ---> 4

4. Lateral line scales 29-38; total vertebrae 39-40; Tigris River basin = Barbus kosswigi
    Lateral line scales 24-27; total vertebrae 37-38; Tigris River basin in A'la River= Barbus sublimus

5. Dorsal fin spine smooth, without denticulations; scales large, 34-43 in lateral line; Tigris River basin and northern Gulf tributaries [total gill rakers 19-22] = Barbus grypus
    Dorsal fin spine with denticulations; scales medium to small, 42-103, mostly 50 or more  ---> 6

6. Head, body and fins with large, dark spots arranged almost in a quincunx pattern; Tigris River basin = Barbus subquincunciatus
    Head, body and fins without large, dark spots although speckling may be present ---> 7

7. Head pike-shaped, tapering and depressed anteriorly [adults very large, reputedly over 2 m long; Tigris River basin [lateral line scales 63-78; total gill rakers 8-12] = Barbus esocinus
    Head not pike-shaped ---> 8

8. Body covered with speckles ?describe size in relation to scales/eye; widespread in Caspian Sea basin and westerrn Iran  [total gill rakers 5-13] = Barbus lacerta
    Body not covered with distinctive speckles ---> 9

9. Caspian Sea and Namak Lake basins ---> 10
    Persian Gulf basins (Tigris, Gulf) ---> 12

10. Lower lip with central flap; Caspian Sea basin and Namak Lake basin [lateral line scales 74-103, usually 80 or more; total gill rakers 9-16] = Barbus mursa
      Lower lip without central flap [lateral line scales 51-85, mostly 75 or less] ---> 11

11. Dorsal fin branched rays modally 7; flank colour gradually lightens from dorsal to ventral (rarely abrupt transition as in B. capito); predorsal length shorter than postdorsal length; Caspian Sea basin [lateral line scales 63-85, mostly 65 or more; total gill rakers 18-21] = Barbus brachycephalus
      Dorsal fin branched rays modally 8; upper part of flank dark, lower light and strongly contrasting; predorsal length equal to longer than postdorsal length; Caspian Sea basin [lateral line scales 51-70, mostly 65 or less; total gill rakers 12-19] = Barbus capito

12. Total gill rakers 7-13 [Tigris River basin; lateral line scales 57-68] = Barbus xanthopterus
      Total gill rakers 14-21 [lateral line scales 60 or less] ---> 13

13. Fourth major row pharyngeal tooth large and molariform; Tigris River and northern Gulf tributaries [47-59 lateral line scales] = Barbus barbulus
      Fourth major row pharyngeal tooth similar in size to third, not molariform [lateral line scales 42-60] ---> 14

14. Dorsal fin origin at or ahead of pelvic fins origin; Tigris River basin = Barbus pectoralis
      Dorsal fin origin behind pelvic fins origin; Tigris River basin = Barbus kersin

Key to the Species of Capoeta

 

Capoeta aculeata

Capoeta barroisi

Capoeta buhsei

Capoeta capoeta

Capoeta damascina

Capoeta fusca

Capoeta trutta

Key to the Species of Carassius

1. Lateral line scales 25-34, mostly 31 or less; gill rakers 35-54, size dependent and mostly 39 or more in adults; anal fin branched rays modally 5; young never with dark spot on caudal peduncle = Carassius auratus
    Lateral line scales 32-36; gill rakers 23-35, mostly 31 or less; anal fin branched rays modally 6; young usually with dark spot on caudal peduncle = Carassius carassius

Key to the Species of Chondrostoma

1.  Caspian Sea basin = Chondrostoma cyri

    Tigris River and Kor River basin = Chondrostoma regium  

Key to the Species of Cyprinion

 

distribution; tabulate characters for comparison

 

Cyprinion kais

Cyprinion macrostomum

Cyprinion milesi

Cyprinion tenuiradius

Cyprinion watsoni  

Key to the Species of Garra

?

1. Caudal fin branched rays modally 16 (85.6% for 132 fish, range 15-17); southeastern Iran = Garra persica
    Caudal fin branched rays modally 17, 16 only rarely ---> 2

2. Dorsal fin branched rays modally 8 (87.1% for 534 fish, range 6-8); southwestern Iran ? sucker structure = Garra rufa
    Dorsal fin branched rays modally 7 (91.5% for 59 fish, range 6-8) ---> 3

3. ?; Eastern Iran = Garra rossica
    ?; Tigris River basin = Garra variabilis

Key to the Species of Gobio

 (key to subspecies of Gobio persus by A. Naseka, Zoological Institute, St. Petersburg)

1. Body and caudal peduncle compressed (caudal peduncle depth at anal fin insertion greater than caudal peduncle width); well-defined spots on the dorsal and caudal fins; Tedzhen River = Gobio gobio
    Body only slightly compressed and the caudal peduncle cylindrical (caudal peduncle depth at anal fin insertion less than or about equal to caudal peduncle width); faint spots on the dorsal and caudal fins; Lake Orumiyeeh and Caspian Sea = Gobio persus ---> 3

 3. Number of lateral line scales 40 to 42 with modes of 40 or 41; total vertebrae 37 to 40 with modes of 38 and 39; connection between the supraorbital and infraorbital head canals usually absent; Lake Orumiyeh = Gobio persus persus
    Number of lateral line scales 41 to 45 with modes of 42 and 43; total vertebrae 38 to 42 with modes of 40 and 41; connection between the supraorbital and infraorbital head canals usually present; Caspian Sea = Gobio persus macropterus

Key to the Species of Hypophthalmichthys

1. Abdomen with a compressed keel extending from the breast (pelvic fins) to the vent; pectoral fins short, not extending past the origin of the pelvic fins; gill rakers a continuous band uniting both sides, roots fused into a spongy mass = Hypophthalmichthys molitrix
    Abdomen with a compressed keel extending from the throat to vent; pectoral fins long, extending past the origin of the pelvic fins; gill rakers free, no spongy mass = Hypophthalmichthys nobilis

Key to the Species of Squalius

 

Leuciscus cephalus

Leuciscus latus

Leuciscus lepidus

Key to the species of Petroleuciscus 

Petroleuciscus persidis

Petroleuiscus ulanus

 

Key to the Species of Rutilus

1. Lateral line scales 47-64, mostly 55-58; swimbladder elongate and conical or pointed posteriorly = Rutilus frisii
    Lateral line scales 39-48, mostly 42-47; swimbladder rounded posteriorly = Rutilus rutilus

Key to the Species of Schizothorax

Schizothorax intermedius

Schizothorax pelzami lips thick

Schizothorax zarudnyi lips thin

Key to the genera and species of Gasterosteidae

1.  Long dorsal fin spines, numbering 3; long pelvic fin spines, both dorsal and pelvic spines exceeding eye diameter in length; scutes (vertical bony plates on flank) large = Gasterosteus aculeatus
     Short dorsal fin spines, numbering 7-11, alternatively sloping left and right; both dorsal and pelvic spines shorter than eye diameter; scutes small = Pungitius platygaster

Key to Persian Gulf  and Sea of Oman drainage species of the Family Gobiidae

 

see murdy

1. Lateral series scales large, 28-36; eyes not protruding = Glossogobius giuris
   
Lateral series scales minute, over 90; eyes protruding above dorsal head profile ---> 2

2. 4-5 first dorsal fin spines; anal fin base and second dorsal fin base 34% or more of standard length; 2 canine teeth internal to the lower jaw symphysis = Boleophthalmus dussumieri
    10-14 first dorsal fin spines; anal fin base and second dorsal fin base 27% or less of standard length; no canine teeth internal to the lower jaw symphysis  = Periophthalmus waltoni

Key to Caspian Sea genera of the Family Gobiidae

Some genera are monotypic or have only a single species in the Caspian Sea basin and so the keys terminates there. Speciose genera have separate keys below.

Note that a Rhinogobius species is recorded from the Tedzhen (= Hari) River basin in Iran as an exotic (see Gobiidae species accounts for description). This is the only goby outside the Caspian Sea basin and coastal waters of the Persian Gulf/Sea of Oman in Iran.

The following key is modified after Miller in Miller (2003):-

1. Suborbital papillae with longitudinal row a immediately below eye and having at least one short side row; cheek with several short transverse rows, none reaching lower eye margin; snout with longitudinal rows s1 and s2 or, if transverse interorbital and snout rows, a perianal organ is present---> 2
    Suborbital papillae in transverse rows; no row a; snout with transverse rows s1 and s2; no perianal organ---> 3

2. Otic transverse row tra long, from level of anterior oculoscapular canal to near row b, and cheek transverse row descending through row d to near row e =
    Hyrcanogobius bergi
    Otic transverse row tra short, distant from row b, and no anterior cheek transverse row passing through row d = Knipowitschia

3. Row 5i not below level of row 6i; 6i at or opposite end of row d; scales normal; canals present or absent---> 4
    Row 5i below level of row 6i; 6i separated from posterior end of row d by row 5i; scales non-imbricate or bony tubercles and granules or naked; no canals ---> 7

4. Anterior nostril an elongate tube hanging over lip = Proterorhinus marmoratus
    Anterior nostril elongate but not overhanging lip---> 5

5. Three rows below row b = Mesogobius nonultimus
    Two rows below row b---> 6

6. Four rows before row b = Neogobius
    Five rows before row b = Chasar bathybius

7. Chin barbel and cheek flap present = Benthophilus
    No chin barbel or cheek flap---> 8

8. No scales in both sexes; rows 5i and 6i more or less juxtaposed = Caspiosoma caspium
   
Modified scales or granules in skin (of females at least), or body naked in males; suborbital rows 5s and 6s not distant from other transverse rows---> 9

9. Four transverse infraorbital rows before row b; non-imbricate scales present = Benthophiloides turcomanus
    Five or six transverse infraorbital rows before row b; skin with bony granules; snout a duck-bill shape = Anatirostrum profundorum

The following key does not use papillae and head canal characters. It is modified from Mitrofanov (2003) as translated courtesy of Dmitri Ponomarenko:- CHECK Below species against ones above

1. Body naked ---> 2
    Body covered with regular ctenoid scales ---> 4
    Body covered with long spikes = Benthophiloides brauneri

2. Snout narrow and long = Anatirostrum profundorum
   
Snout regular, not elongated ---> 3

3. Tail rounded; body covered with sharply bordered dark spots ---> Caspiosoma caspium
   
Tail pointed; body without spots Benthophiloides turcomanus

4. Anterior nostril elongated into a tube that hangs over lip ---> Proterorhinus marmoratus
    Anterior nostril not as above---> 5

5. Second dorsal fin short, with less than 12 branched rays; small fishes less than 50 mm ---> 6
    Second dorsal long, with more than 12 branched rays ---> 7 

6. Body covered with scales only in the posterior part; mucous canals open, close to posterior edge of eyes; eyes directed upwards and laterally; body without black spots but with small brownish dots;
    tail rounded and symmetrical, without a dark spot at the base ---> Hyrcanogobius bergi
    Scales on sides of body, with head, throat, belly and back to second dorsal fin scaleless; eyes lateral; body darkly pigmented without stripes; tail symmetrical without a dark spot at tail base ---> Knipowitschia caucasica
   
Body fairly fully covered with scales; eyes pointed upwards; body with dark stripes; body glassy and translucent; tail symmetrical without a basal spot; deepwater species ---> Knipowitschia iljini
    Body fairly fully covered with scales; eyes pointed upwards; body without stripes; back with rare brownish dots; body semi-translucent; tail asymmetrical with a dark basal spot ---> Knipowitschia longecaudata

7. Sinciput not covered with scales (Mesogobius) ---> 8
    Sinciput and occiput covered with scales ---> Neogobius

8. Up to 50 transverse scale rows; sinciput and occiput entirely bare; sides carry oblique stripes directed forwards; colour light yellow --->Mesogobius gymnotrachelus (included in Neogobius by some authors)
    More than 70 transverse scale rows; sinciput bare, occiput partially scaled; stripes not developed; colouration pale grey ---> Mesogobius nonultimus
    60-70 transverse scale rows; sinciput and occiput bare; sides carrying 5 black spots ---> Mesogobius nigronotatus

Key to species of the genus Benthophilus

check charactesr against text in Boldyrev abnd Bogut

The following key is modified after Pinchuk and Miller in Miller (2004) and Boldyrev and Bogutskaya (2007). It includes only those species recorded from Iran and the works cited have keys to all Caspian Sea species.

1. One or two dermal barbels behind jaw angle; first dorsal fin with 0-2 spines, commonly 1; tubercles large and high, not all spinous; tubercles in dorsal row 11-17, in ventral row 9-14 = B. baeri
    A dermal fold or lobe behind jaw angle (if absent, tubercles vertically elongated); first dorsal fin spines 3-4 (rarely 2); tubercles in dorsal row 18 or more, in ventral row 14 or more ---> 2

2. Tubercles vertically elongated, curved and crest-like, rear edges spinulose; temporal and occipital region without large tubercles; extremely small or no granules on head; back without brown bands ---> 3
   
Tubercles conical and tipped by spines; temporal and occipital region with large tubercles; tubercles and granules on head; back with or without brown bands ---> 4

3. Temporal and occipital region of head with granules; tubercles in dorsal row incomplete, starting at dorsal fin origin; dermal fold at mouth angle well-developed, 1.2 times eye diameter = B. ctenolepidus
    Temporal region of head naked; tubercles in dorsal row complete, starting just behind head; dermal fold small, less than eye diameter = B. pinchuki
   
4. Tubercle rows distinct but tubercles relatively small (23-27, modally 25); upper head and body densely covered with very small granules; no dark brown bands on back ---> B. macrocephalus
    Tubercles distinct, relatively large (25-30, modally 28); granules on temporal and occipital area small and sparse, or if slightly larger then not forming real tubercles; bands present on back ---> B. leobergius

Key to spawning males of the genus Benthophilus

The following key is modified after Boldyrev and Bogutskaya (2007). It includes only those species recorded from Iran and the work cited has keys to all Caspian Sea species.

1. Small and thornless tubercles on body; total vertebrae 24-27, usually 25-26 ---> B. baeri
    Body naked; total vertebrae 26-32, usually 27-31 ---> 2

2. No dark blotches on back and flanks ---> 3
    Three dark blotches on back and flanks ---> 4

3. Dermal fold behind jaw angle with rounded free margin, deep and long (12-24% head length and larger than eye diameter); caudal vertebrae 18-21, usually 19-20, total vertebrae 28-30, usually 28-29 ---> B. ctenolepidus
   
Dermal fold behind jaw angle triangular and small (3-11% head length and less than eye diameter); caudal vertebrae 20-23, usually 21-22, total vertebrae 30-32 ---> B. pinchuki

4. Upper jaw projecting over lower jaw; precaudal vertebare 10-11, usually 11 ---> B. leobergius
   
Upper jaw not projecting over lower jaw; precaudal vertebrae 9-10, usually 9 ---> B. macrocephalus

Key to Caspian Sea species of the genus Knipowitschia

The following key is modified after Miller in Miller (2004). It includes K. longecaudata although this species has yet to be confirmed from Iran.

1. Anterior oculoscapular canals more or less separate in midline of posterior interorbit, with pore κ double, and canals extending anteriorly through
    interorbit of variable extent, typically absent; preopercular canal present or absent = K. iljini
    Anterior oculoscapular canals united at posterior interorbit, with a single median pore κ, and canals extending anteriorly to pores λ; propercular canal present ---> 2

2. Posterior oculoscapular canal always absent; males with numerous thin flank bars of varying distinction; first dorsal fin with rear black mark at fin margin;
    vertebrae modally 32-33 (range 32-35) = K. longecaudata
   
Posterior oculoscapular canal usually present; males with about 4 conspicuous flank bars; first dorsal fin with black blotch within edge of fin; vertebrae
    modally 31-32 (range 30-33, posterior oculoscapular canal present if mode is 32) = K. caucasica

Key to Caspian Sea species of the genus Neogobius

The following key is modified after Miller and Vasil'eva in Miller (2003). It includes N. gymnotrachelus although this species has yet to be confirmed from Iran.

1. Pelvic fin anterior membrane with angular lateral lobes; lobes about one-sixth to almost one-half width of anterior edge of membrane ---> 2
    Pelvic fin anterior membrane with rounded and shallow lateral lobes; lobes not more than one-sixth width of anterior edge of membrane, or lacking entirely
    ---> 5 

2. Posterior nostril markedly distant from edge of orbit; anterior nape with cycloid scales; rear of first dorsal fin with a large dark spot = N. caspius
   
Posterior nostril near edge of orbit; anterior nape with ctenoid or cycloid scales; rear of first dorsal fin without a dark spot ---> 3

3. Lateral series scales usually 49-54; lateral lobes of pelvic fin anterior membrane small, not more than one-fifth width of rear edge; upper lip width 0.4-0.67
    lateral preorbital width (lip to orbit); nape scales cycloid; pelvic fin almost reaches the anal fin (0.9 distance) or extends beyond the anal fin
    origin = N. ratan
   
Lateral series scales usually 54-76; lateral lobes of pelvic fin anterior membrane large, at least one-fifth width of rear edge; upper lip width at least 0.6
    lateral preorbital width (lip to orbit), if less than 0.75, then nape scales ctenoid; pelvic fin less than nine-tenths distance to anal fin --->  4

4. Upper lip not markedly swollen, width about 0.6-0.67 lateral preorbit; interorbital distance 0.8-0.9 eye diameter; caudal peduncle depth 0.67-0.75 length =
    N. gorlap
   
Upper lip moderately swollen, width about 0.75 to more than length lateral preorbit; interorbital distance 0.4-0.8 eye diameter; caudal peduncle depth  0.75
    to more than length = N. cyrius

5. Nape naked before level of preopercle = N. gymnotrachelus
    Nape scaled ---> 6

6. At least anterior nape scales cycloid; first dorsal fin with large dark spot at rear; lateral series scales usually 49-55 = N. melanostomus
    Nape scales ctenoid; first dorsal fin without large dark spot; lateral series scales usually 55-70 ---> 7

7. Pelvic fin disc two-thirds distance to anal fin origin; pelvic fin anterior membrane anterior lobes shallowly convex; angle of jaw below pupil of eye; three
    transverse infraorbital papillae rows below longitudinal hyomandibular row b = N. syrman
   
Pelvic fin disc 0.9 to more than distance to anal fin origin; pelvic fin membrane anterior lobes small, rounded, less than one-fifth rear edge width; angle of jaw
    anterior to orbit; two transverse infraorbital papillae rows below longitudinal hyomandibular row b = N. fluviatilis

The following key is modified from Mitrofanov (2003) as translated courtesy of Dmitri Ponomarenko:- CHECK species below against ones above

1. Head breadth approximately equal to depth; first dorsal fin with 6 rays, colourless; second dorsal fin the same along its length; nostrils strongly displaced forward so anterior nostril almost touches upper lip and
    posterior nostril is far from the eye ---> N. caspius
    Head breadth markedly greater than depth; first dorsal fin with 6 rays, carrying transverse stripes, often zig-zagging ---> N. gorlap
    Head breadth approximately equal to depth; first dorsal fin with 7 rays, colourless; second dorsal fin becomes markedly lower posteriorly ---> N. bathybius
    Head breadth approximately equal to depth; first dorsal fin carrying a sharp, dark, almost black spot; first dorsal fin has 6 rays, rarely 7; second dorsal fin slightly increases in height anteriorly ---> N. melanostomus
   
First dorsal fin with 6 rays and with transverse stripes; second dorsal fin height equal along its length; upper jaw overlaps lower jaw ---> N. ratan
    Head breadth approximately equal to depth; first dorsal fin with 6 rays and longitudinal stripes running along rays; second dorsal fin rises towards the middle; lower jaw juts forward ---> N. syrman
    Head breadth approximately equal to depth; first dorsal fin with 6 rays, without stripes or spots; second dorsal fin gradually decreasing in height towards rear ---> N. fluviatilis

Key to the genera and species of Mugilidae

1. Posterior end of maxilla not curved below tip of premaxilla, but straight; jaw end on line of gape; adipose eyelid well-developed, enclosing eye over much of anterior and posterior fields of iris, so pupil is covered by an oval slit; pyloric caeca 2; marine = Mugil cephalus
    Posterior end of maxilla curved below tip of premaxilla, visible behind corner of closed mouth; jaw end on below line of gape; adipose eyelid weakly-developed, not reaching pupil of eye; pyloric caeca 6-9 ---> 2

2. Branched second dorsal fin rays 7; anal branched rays 8; pectoral fin long, reaching dorsal fin level; Tigris River, Gulf = Liza abu  check caeca?
    Branched second dorsal fin rays usually 9; anal fin branched rays 9; pectoral fin short, not reaching dorsal fin level; Caspian Sea ---> 3

3. Pyloric caeca equal in length; scales of head and back with one groove; oral edge of preorbital moderately concave ---> Liza aurata
    Pyloric caeca in two groups, 3-5 short and 3-4 long; scales of head and back with 2-7 or more grooves; oral edge of preorbital bone deeply notched = Liza saliens

Key to the species of Cyprinodontidae

?

1. Lateral line scales 36-47; Zagros Mountains west of Esfahan = Aphanius vladykovi
    Lateral line scales 24-35, mostly 31 or less ---> 2

2. Total dorsal fin rays ; total anal fin rays ; Genu Hot spring near Bandar Abbas = Aphanius ginaonis
    Total dorsal fin rays ; total anal fin rays ---> 3

3. Males* lemon-yellow with two broad bars on caudal fin; females ?; coastal streams of the Persain Gulf and Sea of Oman, and the Hamun-e Jaz Murian basin = Aphanius dispar
     Males not lemon-yellow ?? ---> 4

4. Females* with flank stripes; males?; Lake Maharlu basin near Shiraz = Aphanius persicus
    Females with flank spots ---> 5

5. Females with lozenge-shaped spot at caudal fin base; males?  Kor River basin = Aphanius sophiae
    Females   ; males? = Aphanius mento

* Almost any sample will contain both males and females, clearly distinguished by colour and pigment patterns.

Key to the genera and species of Percidae

1. Canine teeth absent; prominent bars on flank; anal fin branched rays usually 8-9, rarely 10; lateral line scales 77 or less = Perca fluviatilis
   
Canine teeth present; no bars on flank; anal fin branched rays rarely 10, usually 11 or more; lateral line scales 78 or more ---> 2  

2. More than 18 branched rays in the dorsal fin; interorbital width equal to or less than eye diameter = Sander lucioperca
    Less than 19 branched rays in the dorsal fin; interorbital width greater than eye diameter = Sander marinum

Key to the Salmonidae

NEEDS to be checked

1. Teeth in lower jaw absent or weak and brush-like; scales large, 13 or less from dorsal fin origin to lateral line, 100 or less in lateral line CHECK; caudal fin clearly forked ---> 2
    Teeth in lower jaw strong and conical; lower jaw long, extending back to or past mid-eye; scales small, 19 or more from dorsal fin origin to lateral line, 115 or more in the lateral line CHECK; caudal fin truncate ---> 3

2. Mouth small? define; snout projects beyond lower jaw; ?, lower jaw not projecting markedly beyond upper jaw CHECK; teeth in roof of mouth few or absent; head length usually 4 times or more in standard length; body not pike-like = Coregonus lavaretus
    Mouth large?; snout not projecting; lower jaw obviously projecting beyond upper jaw; teeth in roof of mouth in broad bands; head length usually less than 4 times in standard length; body pike-like ?fusiform? = Stenodus leucichthys

3. Major anal fin rays 12 or more; anterior edge of preoperculum meeting orbital bones; pyloric caeca 140-249; Caspian Sea = Oncorhynchus keta
    Major anal fin rays 13 or less; gap between anterior edge of preoperculum and orbital bones; pyloric caeca 23-66 ---> 4

4. Body with dark spots on light background; vomer with teeth on head and shaft; lower fins without white leading edge; Caspian Sea = Salmo trutta
    Body with light spots on dark background; vomer with teeth on head only; lower fins with white leading edge; ? = Salvelinus fontinalis

Key to the species of Siluridae

1.  Teeth robust and long (snaggly, catching on flesh); the upper and lower jaws meet at a dorsal and superior position; distinctly and coarsely serrate pectoral fin spine posteriorly; colour light; Tigris River basin = Silurus triostegus
    Teeth short and weak (not snaggly); upper and lower jaws meeting at an antero-dorsal position; finely serrate or smooth pectoral spine posteriorly; colour dark; Caspian Sea, Lake Orumiyeh and Tedzhen River basins= Silurus glanis 

Key to the species of Sisoridae

1. Head and body dorso-laterally without striated or elongate tubercles; Tigris River, Gulf = Glyptothorax silviae
   
Head and body dorso-laterally with striated or elongate tubercles; Tigris River ---> 2

2. Thoracic adhesive apparatus ("sucker") wider than long or about equal; caudal peduncle short (5.9-6.0 in standard length) = Glyptothorax kurdistanicus
    Thoracic adhesive apparatus markedly longer than wide; caudal peduncle long (4.0-5.3 in standard length) ---> 3

3. Pectoral fin extends to origin of pelvic fin (pectoral fin length in standard length 3.8-4.1); head long (4.0-4.2 in standard length) = Glyptothorax cous
    Pectoral fin does not extend to origin of pelvic fin (pectoral fin length in standard length 4.3-4.6); head short (4.3-4.5 in standard length) = Glyptothorax armeniacus

Brian W. Coad (www.briancoad.com)