Polysteganus, Klunzinger, 1870

Iwatsuki, Yukio & Heemstra, Phillip C., 2011, Polysteganus mascarenensis, a new sparid fish species from Mascarene Islands, Indian Ocean, Zootaxa 3018 (1), pp. 13-20 : 19

Key to species of the Polysteganus from Indian Ocean

1a. Large oval dark blotch on lateral line below 5th & 6th dorsal-fin spines................................ P. undulosus

1b. No dark blotch on lateral body.......................................................................... 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; gill-rakers 10‒13..................................................... 3

3a. 7 or 8 longitudinal blue stripes on body............................................................ P. baissaci

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

4a. No blue or cobalt spotted lines on reddish orange body; 6 ½ scale rows between 10th dorsal-fin spine base and lateral line; orbit diameter 2.2‒2.3 in snout length; caudal fin weakly forked, nearly truncate if widely spread; Fig. 1A&B ); distinct bony bulge before and above eye in specimens ~ 60 cm SL (bulge probably not apparent in juveniles; Fig. 1A&B )............................................................................................... P. mascarenensis n. sp.

4b. 7 or 8 irregular blue or cobalt spotted lines on reddish yellow body; 5 ½ scale rows between 10th dorsal-fin spine base and lateral line; snout shorter, its length 0.9‒1.4 times orbit diameter; caudal fin forked; no bony bulge both before and above eye.................................................................................... P. coeruleopunctatus

Figures

FIGURE 1. Polysteganus mascarenensis n. sp. A), SAIAB 84109 (holotype), 600 mm SL; B) SAIAB 84095 (paratype), 574 mm SL. Both were photographed by D. Tweddle. Arrow shows the height of posterior end of upper jaw under first two infraorbitals.