Thysanophrys

Key to the Western Indian Ocean Species of Thysanophrys

1. A single papilla on upper surface of eye................................................................... 2

- No papillae on upper surface of eye....................................................................... 3

2. A finger-like papilla on eye; A fin rays 13 (rarely 12); preorbital spines 2–4 (rarely 1)....................... T. celebica

- A tiny wart-like papilla on eye; A fin rays 12; preorbital spine single.................................... T. papillaris

3. DSC scales 9–12...................................................................................... 7

- DSC scales 4–8...................................................................................... 4

4. DSC 4–5........................................................................................... 5

- DSC 6–8 (various western Indian Ocean locales)........................................................... 6

5. DSC 5; SNL in HL 2.8–3.3 times; usually 4 C dark bands; D spines I, VIII; two or more dark saddles crossing back under D1 fin......................................................................................... T.springeri

- DSC 4–5; SNL in HL 3.7–4.0 times; 3 C dark bands; D spines I, VII; a dark saddle crossing back under entire D1 fin (Sri Lanka)..................................................................................... T. tricaudata

6. Nasal spine with elongate base, height about ½ height of preocular spine height; SNL going about 2.8–3.3 times in HL; iris lappet with short branches with bifurcate tips....................................................... T. chiltonae

- Nasal spine base not elongate, height of spine about equal to preocular spine height; SNL going about 3.2–3.5 times in HL; iris lappet crenate................................................................................. T. randalli

7. Preocular spine single; suborbital ridge with 6–9 large spines........................................ T. longirostris

- Preocular spines 6; suborbital ridge with about 25 small spines (Somalia)................................... T. rarita