Paralichthys, Girard, 1858

Díaz de Astarloa, Juan M., Munroe, Thomas A., Béarez, Philippe, Gonzalez-Castro, Mariano & Castellini, Damián L., 2018, External morphology, postcranial and appendicular osteology of three southwestern Atlantic flatfishes (Paralichthys, Paralichthyidae), and comparisons with other congeneric species, Neotropical Ichthyology 16 (2), pp. 1-21 : 14

Key to species of Paralichthys of the Atlantic Ocean

1a. Ctenoid scales on one or both sides of the body ........... 2

1b. Cycloid scales on both sides of the body ...................... 4

2a. Lateral-line scales 93 to 112. Gill rakers on lower limb of first gill arch 9 to 12. Two conspicuous black spots on the ocular side, one below the curve of the lateral line, the other on the lateral line just anterior to the caudal peduncle ...................... Paralichthys patagonicus

2b. Lateral-line scales 55 to 81. Gill rakers on lower limb of first gill arch 7 to 10. Three conspicuous ocellated spots forming a triangle on the ocular side, two ocelli located on a horizontal line with one above and the other below the lateral line and both located near the dorsal and ventral body margins, the third ocellus situated on the lateral line anterior to the caudal peduncle ............... 3

3a. Ctenoid scales on both sides of body. Lateral-line scales 77 to 81. Distal margin of ocular-side pelvic fin with a small, oblong black spot................ Paralichthys isosceles

3b. Ctenoid scales on ocular side of body, cycloid scales on blind side of body. Lateral-line scales 55 to 72. No spot on distal margin of pelvic fin of ocular side ......... .................................................. Paralichthys triocellatus

4a. Three to five prominent ocelli on ocular side of body..... 5

4b. No prominent ocelli on ocular side of body.................. 7

5a. Gill rakers on lower limb of first gill arch 15 or more. Dorsal-fin rays 84 to 95. Anal-fin rays 65 to 74. Lateral-line scales 95 to 110. Five prominent ocellated dark spots on posterior half of ocular side of body ...... ...................................................... Paralichthys dentatus

5b. Gill rakers on lower limb of first gill arch 8 to 12. Dorsal-fin rays 73 to 84. Anal-fin rays 58 to 65. Laleral-line scales 83 to 98. Three or four ocellated spots on ocular side of body.......................................... 6

6a. Eyes relatively large and close set, nearly meeting, separated only by a narrow, bony ridge. Four large ocelli each with a dark center encircled by a ring of lighter colour on ocular side of body, ocelli arranged in a trapezoid with 2 in midbody (one above the other on opposite sides of the lateral line) and 2 on the body (one above the other on opposite sides of the lateral line) at a point slightly anterior to caudal peduncle............... Paralichthys oblongus

6b. Eyes separated by a flat space without a bony ridge. Three prominent ocellated dark spots on body arranged in a triangle with 2 (one above the other) in the midbody and 1 on the lateral line in the posterior part of the body ........................... Paralichthys albigutta

7a. Gill rakers on lower limb of first gill arch 13 to 18. Interorbital width wide, 9.1 to 16.6 % of head length (HL). Eye diameter short, 8.0 to 15.6 % of HL. Pectoral-fin length short, 30.4 to 47.7% of HL ............ ................................................ Paralichthys orbignyanus

7b. Gill rakers on lower limb of first gill arch 7 to 12. Interorbital width narrow, 5.6 to 14.5 % of head length (HL). Eye diameter long, 13.6 to 23.2 % of HL. Pectoral-fin length long, 41.7 to 61.3% of HL.............. 8

8a. Dorsal-fin rays 67 to 75. Anal-fin rays 51 to 56. Caudal-peduncle depth 12.5 to 14.3 % of standard length (SL) .............................. Paralichthys brasiliensis

8b. Dorsal-fin rays 74 to 91. Anal-fin rays 58 to 72. Caudalpeduncle depth 9.2 to 11.7 % of standard length (SL). 9

9a. Body depth greater than 47% (47.6 to 52.5%) of SL. Blind side of larger specimens dusky. Lateral-line scales 110 to 119 ................... Paralichthys squamilentus

9b. Body depth 47% or less of standard length, (usually 42.2 to 45.5 %). Blind side immaculate or dusky. Lateral-line scales 81 to 99.......................................... 10

10a. Dorsal-fin rays 74 to 78. Anal-fin rays 58 to 59. Gill rakers on lower limb of first arch 11 to 12 ................... ....................................................... Paralichthys tropicus

10b. Dorsal-fin rays 76 to 91. Anal-fin rays 62 to 72. Gill rakers on lower limb of first arch 9 to 11 .................... ................................................. Paralichthys lethostigma