Ophthalmolycus polylepis can be distinguished from its congeners by the following combination of characters: two posterior nasal pores; epidermal prickles on lips; gill slit extending ventrally just to below mid-pectoral fin base; interorbital pore present; two postorbital pores; lateral line triple with ventral, mediolateral and dorsolateral branches; scales extending anteriorly to predorsal area, abdomen, pelvic fins base, and pectoral fins base and axil; vertebrae asymmetrical 22 + 76; dorsal fin origin associated with vertebra 5; pectoral fin rays 18; six branchiostegal rays; oral valve overlapping the anterior edge of vomer; two rows of palatine teeth anteriorly; two vestigial pyloric caeca and 2 pseudobranch filaments; pelvic fin and vomerine teeth present (Ref. 84360).