Ceratonereis Kinberg, 1865

Conde-Vela, Víctor Manuel, 2021, Revision of Ceratonereis Kinberg, 1865 recorded from the Caribbean Sea, with description of two new Ceratonereis species and a new combination of Platynereis Kinberg, 1865, Zootaxa 5026 (3), pp. 301-343 : 339

Key to atokes of American Ceratonereis Kinberg, 1865

(Modified from de León-González 2009) 1

1. Dorsal ligules reducing greatly their size and disappearing from middle chaetigers.................................. 2

- Dorsal ligules present throughout body, often reducing progressively their size toward posterior chaetigers.............. 3

2. Blades of notopodial and neuropodial falcigers, in middle and posterior body, with nearly rounded distal tip (i.e. unidentate).................... Ceratonereis excisa (Grube & Müller in Grube, 1873) (Santa Catarina Island, Santa Catarina, Brazil) 2

- Blades of both notopodial and neuropodial falcigers in middle and posterior body with a small tooth at the distal tip (i.e. bidentate)............... Ceratonereis longicirrata Perkins, 1980 (Hutchingson Island, Florida, United States of America)

3. Blades of both notopodial and neuropodial falcigers, in middle and posterior body, with a small tooth at the distal tip (i.e. bidentate)........................................................................................... 4

- Blades of notopodial and neuropodial falcigers, from middle and posterior body, with rounded distal tip (i.e. unidentate)... 6

4. Jaws broad, teeth coarse............................................................................... 5

- Jaws narrow, teeth minute.......................... Ceratonereis nancyae n. sp. (Buenavista, Quintana Roo, Mexico)

5. Antennae lanceolate; dorsal ligules in chaetigers 10–13 shorter than the half of median ligules..................................................................................... Ceratonereis mirabilis Kinberg, 1865 (9ºS Brazil)

- Antennae subulate; dorsal ligules in chaetigers 10–13 longer than the half of median ligules.................................................................................. Ceratonereis gracilis ( Webster, 1884) reinst. ( Bermuda)

6. Both dorsal and ventral ligules subequal throughout body................................................................................... Ceratonereis singularis Treadwell, 1929 (San Jose Island, Baja California Sur, Mexico)

- Both dorsal and ventral ligules greatly diminishing their size toward posterior end.................................................................................. Ceratonereis maya n. sp. (Contoy Island, Quintana Roo, Mexico)