Key to the longiventralis -species group

1 A central and no posterior ocellus, orbit length 3.9–5.2% SL and 17–24% HL, gill-filament length 1.3–2.7% SL, otolith ostium length 2.5–3.4% SL and 59–71% sulcus length............................................................. 2

- A central and one posterior ocellus placed just behind midpoint of dorsal fin, orbit length 5.5% SL and 24% HL, gill-filament length 1.3% SL, otolith ostium length 3.5% SL and 73% sulcus length................................. N. zora n. sp.

2 A central ocellus and no anterior ocellus, pectoral-fin rays 27–30, central-ocellus spot covering 9–13 dorsal-fin rays...... 3

- An anterior and a central ocellus, pectoral-fin rays 25–27, central-ocellus spot covering 7–9 dorsal-fin rays.................................................................................................... N. longiventralis

3 Dorsal-fin rays 96–103, anal-fin rays 79–87, total vertebrae 57–60..................................... N. longipes

- Dorsal-fin rays 91–92, anal-fin rays 72–76, total vertebrae 53.................................... N. jonathan n. sp.