KEY TO GENERA OF AMPHINOMINAE SAVIGNY IN LAMARCK, 1818 (MODIFIED FROM SUN & LI 2017)

REMARKS

Paramphinome Sars, 1869 is a nomen nudum because it was included in a species list (Sars 1869); the genus and species were published posthumously by his son (Sars 1872).

1. Caruncle present, variably developed; neuropodia lateral; neurochaetae non-retractile ............................. 2

— Caruncle absent; neuropodia ventral; neurochaetae retractile ..... Hipponoe Audouin & Milne-Edwards, 1830

2(1). Branchiae present on all chaetigers, starting from chaetiger 1 ................................................................... 3

— Branchiae missing in some chaetigers, starting from anterior chaetigers (not from the first) ..................... 4

3(2). Caruncle with a median ridge, concealing lateral plates, never with digitate lobes; spurred neurochaetae without denticles ............................................................................................ Eurythoe Kinberg, 1857 (partim)

— Caruncle with a median ridge and up to four lateral digitate lobes directed posteriorly; spurred neurochaetae with denticles along inner side .................................................................................................................... ............................................ Pherecardites Horst, 1912 (incl. Branchamphinome Hartman, 1967, see above)

4(2). Branchiae present from chaetiger 2-4; eyes commonly present ................................................................. 5

— Branchiae present from chaetiger 6; eyes absent; caruncle with a median ridge and smooth lateral lobes ..... ............................................................................................................................. Benthoscolex Horst, 1912

5(4). Chaetiger 1 dorsally continuous, complete ............................................................................................... 6

— Chaetiger 1 dorsally discontinuous, incomplete ....................................................................................... 7

6(5). Chaetiger 1 with stout, falcate notohooks; caruncle round, sessile, without free lateral wings; neurochaetae bifurcates; harpoon notochaetae with 1 row of denticles .......................... Paramphinome Sars in Sars, 1872

— Chaetiger 1 without notohooks; caruncle stalked, broadly triangular to chordate with free lateral wings; neurochaetae falcate, unidentate; harpoon notochaetae with up to 2 rows of denticles ... Amphinome Bruguière, 1789

7(5). Caruncle small, not extended beyond one chaetiger ................................................................................. 8

— Caruncle large, extended posteriorly beyond more than one chaetiger ..................................................... 9

8(7). Branchiae present on almost all chaetigers .............. Cryptonome Borda, Kudenov, Bienhold & Rouse, 2012

— Branchiae restricted to anterior chaetigers ................................................ Linopherus de Quatrefages, 1866

9(8). Caruncle narrow, longer than wide, with a median ridge ....................................................................... 10

— Caruncle wide, often longer than wide, or wider than long; branchiae from chaetiger 1 ......................... 12

10(9). Caruncle median ridge concealing lateral lobes (visible in lateral view) .................................................. 11

— Caruncle without lateral lobes; branchiae from chaetigers 2-3 ........................ Pareurythoe Gustafson, 1930

11(10).Bifurcate neurochaetae short, thick, shorter tine 0.5-4.0 times longer than handle width; branchiae present from chaetigers 2-4 .................................................................................. Eurythoe Kinberg, 1857 (partim)

— Bifurcate neurochaetae long, thin, shorter tine 10-15 times longer than handle width; branchiae present from chaetiger 4 ....................................................................................................... Alleurythoe Sun & Li, 2017

12(9). Caruncle as long as wide, with a median ridge, with series of foliose lateral lobes ..... Pherecardia Horst, 1886

— Caruncle slightly longer than wide, without median ridge .................................. Hermodice Kinberg, 1857