The small polychaete family Trochochaetidae is monogeneric and had been recorded almost exclusively in the northern hemisphere before this study. During a benthic investigation in the coastal shelf zone off Angola at 15°S several specimens were collected from 84 m depth differing from other members of the family and we described it as a new species herein. The only known African species so far was Trochochaeta kirkegaardi from the eastern Atlantic. Trochochaeta ankeae sp. nov. is characterized by having four minute eyes, a small conical antenna, a nuchal crest projecting through chaetiger 2, by lacking notochaetae on chaetiger 2, by having acicular spines on neuropodia 2 and 3 and a pair of conical papillae ventral on abdomen. A key to all 11 known species (including an unnamed one) is given.

The small, monogeneric family of polychaetes known as Trochochaetidae has been exclusively collected in the northern hemisphere, mainly in temperate–cold environments. Nine species have been described so far including Trochochaeta mexicana sp. nov. described herein, while one species remains unnamed. Only two species had previously been recorded in the eastern Pacific, so T. mexicana sp. nov. is the first record for the family in the tropical Mexican Biogeographic Province. The new species is characterized by having a pair of eyes, acicular neurochaetae on chaetigers 2 and 3, a small knob-like antenna and a nuchal crest projecting through chaetiger 1. Trochochaeta mexicana sp. nov., together with Trochochaeta kirkegaardi, Trochochaeta diverapoda and Trochochaeta cirrifera are the only trochochaetids that have been found exclusively in warm environments.