Key to species of Trochochaeta Levinsen, 1883

1 Chaetiger 2 neuropodia with only long capillaries........................................................... 2

– Chaetiger 2 neuropodia with short capillaries and acicular spines.............................................. 4

2(1) Chaetiger 2 with smooth slender capillaries both in noto- and neuropodia. Occipital antenna present. Capillaries in notopodia maximum until chaetiger 10....................................................... T. watsoni Pettibone, 1976

– Chaetiger 2 notopodia without chaetae; neuropodia with smooth capillaries in anterior row, and spiral capillaries in posterior row and in inferior fascicle. Occipital antenna absent........................................................ 3

3(2) Capillaries in notopodia maximum until chaetiger 19. Pygidium with up to ten cirri............. T. carica (Birula, 1897)

– Capillaries in notopodia maximum until chaetiger 15. Pygidium with up to eight cirri......... T. pettiboneae Dean, 1987

4(1) Chaetiger 2 notopodia with smooth slender capillaries....................................................... 5

– Chaetiger 2 notopodia without chaetae................................................................... 6

5(4) Occipital antenna absent. Capillaries in notopodia maximum until chaetiger 9. Noto- and neuropodial postchaetal lamellae of some anterior chaetigers cirriform................................................. T. cirrifera (Hartman, 1975)

– Occipital antenna present. Capillaries in notopodia maximum until chaetiger 13. Noto- and neuropodial postchaetal lamellae of some anterior segments serrated or fimbriated.................................. Trochochaeta sp. A Gilbert, 1984

6(4) Occipital antenna absent. Capillaries in notopodia at least until chaetiger 20. Postchaetal lamellae on anterior chaetigers (at least from chaetiger 3 to about chaetiger 15) serrated. Caruncle extending to end of chaetiger 1...................... 7

– Occipital antenna present. Capillaries in notopodia maximum until chaetiger 10. Postchaetal lamellae on anterior chaetigers entire, smooth. Caruncle extending to end of chaetigers 1–3................................................... 8

7(6) Notopodial postchaetal lamellae of chaetigers 1 and 2 conical, entire. Capillaries in notopodia maximum until chaetiger 20. Ventral paired papillae from about chaetiger 20..................................... T. multisetosa (Örsted, 1843)

– Notopodial postchaetal lamellae of chaetigers 1 and 2 conical, entire, bifid or trifid. Capillaries in notopodia maximum until chaetiger 25. Ventral paired papillae from chaetigers 40–44.......................... T. franciscana (Hartman, 1947)

8(6) Caruncle extending to end of chaetiger 3.................................................................. 9

– Caruncle not extending beyond chaetiger 2............................................................... 10

9(8) Occipital antenna long, cirriform............................................... T. diverapoda (Hoagland, 1920)

– Occipital antenna short, subtriangular............................................ T. kirkegaardi Pettibone, 1976

10(8) Ventral paired papillae absent............................. T. mexicana Hernández-Alcántara & Solís-Weiss, 2011

– Ventral paired papillae present......................................................................... 11

11(10) Caruncle extending to end of chaetiger 1............................................. T. japonica Imajima, 1989

– Caruncle extending to end of chaetiger 2....................................... T. ankeae Bochert & Zettler, 2013