Petalophthalmus Willemoes-Suhm, 1875

Vicente, Carlos San, Frutos, Inmaculada & Cartes, Joan E., 2014, Petalophthalmus papilloculatus sp. nov. (Crustacea: Mysida: Petalophthalmidae), a new bathyal suprabenthic mysid from the Galicia Bank (NE Atlantic Ocean), Zootaxa 3765 (1), pp. 77-91 : 88

Key to species of Petalophthalmus Willemoes-Suhm, 1875

(modified from Panampunnayil (1982) and Wang (1998); ecological data according to Bartsch (1933); Tattersall and Tattersall (1951); Murano (1970); Kathman et al. (1986); Ledoyer (1995); Vereschchaka (1995); Wang (1998))

1. Eyes flattened and leaf-like, without functional visual elements. Telson apex without pappose setae.................... 2

- Eyes more or less globular in shape, with functional visual elements. Telson apex with pappose setae................... 3

2. Eyes with ocular papilla near the middle inner dorsal margin................................ P. papilloculatus sp. nov. Galicia Bank (NE Atlantic), Bathypelagic, 1536–1809 m

- Eyes without ocular papilla................................................... P. armiger Willemoes-Suhm, 1875 Atlantic, Pacific, Indian and Southern Oceans, Bathypelagic, 900–4572 m

3. Eyestalk with ocular papilla near the middle inner dorsal margin................................ P. oculatus Illig, 1906 NW Arabian Sea, W Indian Ocean and Japan * Mesopelagic, 220–430 m

- Eyestalk without ocular papilla.......................................................................... 4

4. Eye cornea hemispherical; telson apex emarginated in the median region and lateral margins with 12–15 setae increasing in length distally................................................................ P. caribbeanus Tattersall, 1968 Caribbean Sea, Mesopelagic , 329–366 m

- Eye cornea reniform. Telson apex not emarginated in the median region; lateral margins with more than 15 subequal setae.. 5

5. Apex of rostral plate slightly pointed. Eyestalk subequal in length to cornea. Telson apex armed with three serrate setae.................................................................... P. macrops Tchindonova and Vereshchaka, 1991 W Indian Ocean, Mesopelagic , 360–555 m

- Apex of rostral plate blunt. Eyestalk longer than cornea. Telson apex armed with seven serrate setae..... P. liui Wang, 1998 N South China Sea, Epipelagic, 194–219 m