Leocrates Kinberg, 1866

Wang, Zhi, Qiu, Jian-Wen & Salazar-Vallejo, Sergio I., 2018, Redescription of Leocrates chinensis Kinberg, 1866 (Annelida, Hesionidae), Zoological studies (Zool. Stud.) 57 (5), pp. 1-11 : 9-10

Key to species of Leocrates Kinberg, 1866

(modif. Pettibone 1970; references therein)

1 Neurochaetal tips bidentate .......................................... 2 - N e u r o c h a e t a l t i p s e n t i r e, n o t b i d e n t a t e; u p p e r

neurochaetae with very long blades; notochaetae from chaetiger 4; upper jaw single; pharynx without 'papillae'. ..................................................................................... 12

2(1) Notochaetae from chaetiger 5 (rarely 6); pharynx without 'papillae' ........................................................................ 3

- Notochaetae from chaetiger 4 ...................................... 7

3(2) Upper jaw single ........................................................... 4

- Upper jaw double, in form of a bifid fan; lateral antennae twice longer than palps; palpostyles 1/3 as long as palpophores ..................................................................... ........................................... L. diplognathus Monro, 1922 , Macclesfield Bank (16°00'N, 114°30'E), South China Sea

4(3) Nuchal organs horizontal C-shaped ............................. 5

- Nuchal organs L-shaped; anterior eyes twice larger than posterior ones; lateral antennae longer than palps ...... 6

5(4) Anterior eyes twice larger than posterior ones; palpophores twice longer than palpostyles; neurochaetal blades in median chaetigers 5-15 times longer than wide .............................. L. chinensis Kinberg, 1866 Hong Kong (perhaps including L. anonymous Hessle, 1925 , Japan)

- Anterior eyes slightly larger than posterior ones; palpophores three times longer than palpostyles; neurochaetal blades in median chaetigers 3-10 times longer than wide .............................................................. L. claparedii (Costa in Claparède,1868), Mediterranean Sea

6(4) Palpophores 3 times longer than palpostyles; median antenna between posterior eyes .............. L. longicirratus ( Treadwell, 1902) , Saint Thomas, Virgin Islands

- Palpophores 5 times longer than palpostyles; median antenna central to eyes ................................................... ........................................ L. auritus Hessle, 1925 , Japan

7(2) Upper jaw single; pharynx with about 20 papillae ........ 8

- Upper jaw double; pharynx without 'papillae' .............. 10

8(7) Eyes medium-sized; lateral eyes separated, anterior ones twice larger than posterior ones; lateral antennae and palps subequal; nuchal organs horizontal C-shaped; neurochaetal blades 2-12 times longer than wide ........... ...................................... L. giardi Gravier, 1900 , Red Sea

- Eyes large; lateral eyes close to each other, anterior ones slightly larger than posterior ones; lateral antennae larger than palps; nuchal organs U-shaped .................. 9

9(8) Middorsal pharynx papilla as long as palpophores; neurochaetal blades 5-16 times longer than wide ........... .............................. L. oculatus ( Treadwell, 1906) , Hawaii

- Middorsal pharynx papilla 1/4 longer than palpophores; neurochaetal blades 5-11 times longer than wide ........... .......................... L. anomalus Chamberlin, 1919 , Marshall Islands (perhaps including L. papillosus Monro, 1926 Macclesfield Bank (16°00'N, 114°30'E), South China Sea)

10(7) Nuchal organs U-shaped; upper neurochaetal blades over 20 times longer than wide; notochaetae abundant, long ............................................................................. 11

- Nuchal organs L-shaped; upper neurochaetal blades 4 times longer than wide; notochaetae scarce, short ......... .................. L. greeffianus Augener, 1918 , Western Africa

11(10) Anterior eyes twice larger than posterior ones; palpostyles slightly shorter than palpophores; median antenna between posterior eyes ..................................... ...................... L. atlanticus ( McIntosh, 1885) , NE Atlantic

- Anterior eyes slightly larger than posterior ones; palpostyles markedly shorter than palpophores (1/3-1/4 as long); median antenna central to all eyes ................... .................................. L. indicus Horst, 1921 , Banda Sea

12(1) Anterior eyes slightly larger than posterior ones; lateral antennae as long as palps; tips of neurochaetae taper abruptly to fine tips, without guards ................................. ....... L. wesenberglundae Pettibone, 1970 , Gulf of Oman

- Anterior eyes twice larger than posterior ones; lateral antennae 1/3 longer than palps; tips of neurochaetae blunt, guards extended far beyond tips ........................... ................................................................ L. djangkarensis Augener & Pettibone in Pettibone, 1970, Sulu Sea