Philarius Holthuis, 1952

Marin, Ivan & Anker, Arthur, 2011, A partial revision of the Philarius gerlachei (Nobili, 1905) species complex (Crustacea, Decapoda, Palaemonidae), with description of four new species, Zootaxa 2781, pp. 1-28 : 27

Key to the presently known species of Philarius Holthuis, 1952 based on morphology and colour patterns (where known)

1. Suprarbital teeth conspicuous, acute [rostral formula: 7–10 / 1–2; pereiopods with large white areas adjacent to joints; intensely red spots on eyestalks, at dactylar hinge of P2 chelae, within white patches on pleurae etc.]................................................................................................. P. lifuensis ( Borradaile, 1898)

-. Supraorbital teeth absent (at most small blunt lobes adjacent to rostral base)....................................... 2

2. P2 carpus with strong sharp tooth distomesially [rostral formula: 7–9 / 1; dark V-shaped line present dorsally on the carapace]............................................................................... P. imperialis ( Kubo, 1940)

-. P2 carpus without strong sharp tooth distomesially........................................................... 3

3. Dorsal lamina of carapace with most-posterior tooth situated posterior to orbit..................................... 4

-. Dorsal lamina of carapace with most-posterior tooth situated anterior to orbit...................................... 5

4. Body dorsoventrally flattened, depressed; rostrum with 6 teeth (not counting 1 post-orbital tooth); proximal fusion portion of lateral antennular flagellum with ~5 segments; P2 palm with blunt bumps distodorsally [body and appendages transparent, with large white spots and patches]...................................................... P. albimaculatus n. sp.

-. Body somewhat compressed laterally; rostrum with 4 teeth (not counting 1 post-orbital tooth); proximal fusion portion of lateral antennular flagellum with ~11 segments; P2 palm almost straight distodorsally [body and appendages reddish, with small red spots]................................................................................ P. rufus n. sp.

5. Supraocular lobes present; proximal fusion portion of lateral antennular flagellum with ~8 segments; rostrum with tip reaching beyond distal margin of scaphocerite blade [antennular and antennal flagella purplish-blue].............. P. m i n o r n. sp.

-. Supracular lobes absent; proximal fusion portion of lateral antennular flagellum with at least 15 segments; rostrum with tip not reaching distal margin of scaphocerite blade [antennular and antennal flagella pale orange or yellowish]............... 6

6. Proximal fusion portion of lateral antennular flagellum with ~15 segments; scaphocerite with blade broad, ~2.2 times as long as wide; telson relatively broad, with anterior pair of dorsal spines inserted at about half-length of telson [greenish with minute black spots and larger pale or white patches on the abdomen]................................... P. p o l y n e s i c u s n. sp.

-. Proximal fusion portion of lateral antennular flagellum with ~25 segments; scaphocerite with blade narrow, ~2.8 times as long as wide; telson relatively narrow, with anterior pair of dorsal spines inserted posterior to half-length of telson [possibly with large dorsolateral spots on the abdomen].............................................. P. gerlachei ( Nobili, 1905)