Polysteganus

Iwatsuki, Yukio & Heemstra, Phillip C., 2015, Redescriptions of Polysteganus coeruleopunctatus (Klunzinger 1870) and P. lineopunctatus (Boulenger 1903), with two new species from Western Indian Ocean, Zootaxa 4059 (1), pp. 133-150 : 147

Key to species of the Polysteganus from Indian Ocean

1a Large oval dark blotch on lateral line below 5th and 6th dorsal-fin spines in adults, but no dark blotch in 9 cm juveniles; body with 4 or 5 wide blue stripes (more than 1/3 width of black pupil diameter).............................. P. undulosus

1b No dark blotch on lateral body; 7 or 8 narrow blue stripes (less than 1/4 width of black pupil diameter) or lines of blue spots on body if present....................................................................................... 2a

2a Greatest body depth at preopercle vertical edge; lower-limb gill-rakers 14–16......................... P. praeorbitalis

2b Greatest body depth at pectoral-fin base; lower-limb gill-rakers 10–13............................................ 3

3a Body with 7 or 8 longitudinal blue stripes.......................................................... P. baissaci

3b No longitudinal blue stripes or lines of blue spots on body..................................................... 4

4a Caudal fin weakly forked, nearly truncate if widely spread; distinct bony bulge before and above eye in specimens about 60 cm SL (bulge probably not apparent in juveniles); body reddish orange, without lines of blue spots........... P. mascarenensis

4b Caudal fin forked; no strong bony bulge both before and above eye; body reddish yellow often with clear irregular lines of blue spots................................................................................................ 5

5a Scale rows between 5th dorsal fin spine and lateral line 4½; no irregular lines of blue spots; rear margin of membrane of branchiostegal rays yellow, plus yellow color on a few body scales just above upper pectoral-fin base................................................................................................... .. Polysteganus cerasinus n. sp.

5b Scale rows between the 5th dorsal fin spine and lateral line 5½–7½; no or 7–8 irregular lines of blue spots; rear margin of membrane of branchiostegal rays white (not yellow).......................................................... 6

6a Blue iridescence in each body scale on dorsal and lateral sides of body visible at some angles, and no irregular lines of blue spots; upper caudal-fin lobe yellow, lower red..................................... Polysteganus flavodorsalis n. sp.

6b No blue iridescence in body scales on dorsal and lateral side; 7 or 8 irregular lines of blue spots on body, visible at some angles; both caudal-fin lobes with pink or red membranes...................................................... 7

7a Scale rows above lateral line 6½; pored lateral-line scales 51 or 52; 7 or 8 faint irregular lines of blue spots on body, visible at some angles; dorsal-fin rays reddish pink but with no bright yellow upper margin; canines large, both upper and lower canines on both jaws usually visible even when mouth closed; body deeper, 44–46% (mean 44%) of SL ( Figs. 1 A, 2A)............................................................................................... P. coeruleopunctatus

7b Scale rows above lateral line 7½; pored lateral-line scales 53–55; 7 or 8 distinct irregular lines of blue spots on body (often present even in preserved specimens); dorsal-fin rays reddish pink or orangish red with bright yellow upper margin; canines somewhat smaller, generally only upper canines visible when mouth closed; body somewhat slender, 40–43% (mean 42%) of SL ( Figs. 1 B, 2B)........................................................................ P. lineopunctatus

Figures

FIGURE 1. Polysteganus coeruleopunctatus A and P. lineopunctatus (B). A), HUJF 20120, 226 mm SL, Eilat, Israel, Red Sea, photographed by D. Golani; B), SAIAB 82139, Mozambique, southwestern Indian Ocean (21 ° 35 ' S, 35 ° 32.3 ' E), photographed by O. Alvheim.