Key to Indo-West Pacific species of Trachinotus

1a One to seven dark spots on or near lateral line (spots usually absent in specimens smaller than about 10–15 cm FL); segmented dorsal-fin rays 20–26; anal-fin pterygiophores inserting in first interhemal space typically 3 (Fig. 1, Table 1)............ 2

1b No spots on or near lateral line at any size; segmented dorsal-fin rays 18–20 (except 21–23 in T. africanus); anal-fin pterygiophores inserting in first interhemal space typically 2........................................................ 5

2a Adults with black spots in fresh specimens; no large spot above pectoral fin in adults............................... 3

2a Adults with silvery-gray spots in fresh specimens; 1 or 2 large spots above pectoral fin in adults....................... 4

3a Largest spot on side of adults usually smaller than or approximately size of iris diameter; adults with 2-6 spots (usually 3) spots on sides; height of dorsal-fin lobe 18.9–46.0% FL, mean 28.9%, in specimens> 200 mm FL (broadly distributed in Indo-West Pacific)..................................................................................... T. baillonii

3b Largest spot on side of adults distinctly larger than iris diameter; adults typically with 1 or 2 spots on side; height of dorsal-fin lobe 16.1–21.5% FL, mean 18.1%, in specimens> 200 mm FL (Marquesas Island endemic)............... T. macrospilus

4a Adults typically with only one spot above pectoral fin; vomerine tooth patch consistently round or triangular-shaped; segmented dorsal-fin rays 22–24, usually 22 or 23; segmented anal-fin rays 19–22, rarely 22 (Indian Ocean including Western Australia)...................................................................................... T. botla

4b Adults with two spots above pectoral fin; vomerine tooth patch usually chevron shaped; segmented dorsal-fin rays 23–25, usually 24 or 25; segmented anal-fin rays 22–24 (Eastern Australia, Lord Howe and Norfolk islands)........... T. coppingeri

5a Segmented dorsal-fin rays 21–23; segmented anal-fin rays 19–21; axillary base beneath pectoral fin often with black ring-like blotch (Western Indian Ocean, Gulf of Oman and Bali)............................................... T. africanus

5b Segmented dorsal-fin rays 18–20; segmented anal-fin rays 16–18; axillary base beneath pectoral fin without black ring-like blotch.............................................................................................. 6

6a Supraoccipital bone of skull becoming broad and sausage-shaped in adults (Fig. 19A), this character easily observed by simple dissection along midline of skull; in life, anal-fin yellow; teeth in narrow band on tongue, persisting to about 50 cm FL (Persian Gulf, Pakistan, India, China and southern Japan)................................................... T. mookalee

6b Supraoccipital bone of skull thin and blade-like in adults (Fig. 19B); in life, color of anal fin variable, yellow or brownish with orange anterior margin; tongue toothless (except 2 or 3 slender teeth rarely present in small specimens of T. blochii)...... 7

7a Supraneural bone a swollen inverted tear-drop, becoming oval-shaped in large adults (Fig. 20); in life, anal-fin lobe brownish with anterior margin orange; nasal bone not swollen in adults (broadly distributed in Indo-West Pacific).......... T. blochii

7b Supraneural bone not swollen as above, shaped like an inverted “L” with the short arm projecting anteriorly; in life, anal-fin lobe yellow; nasal bone greatly swollen (hyperostotic) in adults (Eastern and northern Australia, South China Sea and southern Japan)......................................................................................... T. anak