Key to genera of Hesioninae Grube, 1850 fide Pleijel, 1998

(modif. Rizzo & Salazar-Vallejo 2014)

1 Prostomium with palps; median antennae present or absent.................................................... 2

- Prostomium without palps; median antennae absent; pharynx unarmed................ Hesione Savigny in Lamarck, 1818

2(1) Palps biarticulate; parapodia sesquiramous (with dorsal cirri but without notochaetae), or biramous.................... 3

- Palps simple; parapodia sesquiramous; median antenna absent......................... Elisesione Salazar-Vallejo, 2016

3(2) Pharynx unarmed; parapodia sesquiramous; neurochaetal blades bifid, without guards......... Dalhousiella McIntosh, 1901

- Pharynx with upper and lower jaws, sometimes upper one double; parapodia sesquiramous or biramous................. 4

4(3) Anterior chaetigers without notochaetae, middle and posterior ones biramous; neurochaetal blades often with guards...... 5

- All chaetigers sesquiramous; pharynx upper jaw double, T-shaped, lower jaw single, fang-shaped; neurochaetal blades bidentate, without guards................................................................ Leocratides Ehlers, 1908

5(4) Nuchal organs without lateral projections, sometimes projected posteriorly........................................ 6

- Nuchal organs L-shaped, lateral projections often extended beyond lateral prostomial margins........................ 9

6(5) Prostomial posterior region reduced, as long as, or smaller than anterior one; nuchal organs lobes horizontal C-shaped, never pigmented; pharynx with upper and lower jaws single, fang-shaped............................................. 7

- Prostomial posterior region projected posteriorly, often as long as prostomial anterior region, or longer than it, rarely wider distally (in too contracted specimens this region can be collapsed); nuchal organs lobes U-shaped, sometimes pigmented... 8

7(6) Neurochaetal blades bidentate, guards usually present; notochaetae from chaetiger 5, subdistally denticulate, denticles coarse or fine...................................................................... Leocrates Kinberg, 1866 restr.

- Neurochaetal blades unidentate, sometimes with guards surpassing main tooth; notochaetae from chaetiger 4, smooth......................................................................................... Paraleocrates n. gen.

8(6) Pharynx with upper jaw double, T-shaped, lower one transverse plate; neurochaetae often brownish........................................................................................... Dalhousia McIntosh, 1885 reinstated

- Pharynx with upper and lower jaws single, fang-shaped; sometimes with a circlet of round denticles; neurochaetae pale, not brownish........................................................................... Paradalhousia n. gen.

9(5) Pharynx with upper and lower jaws single, fang-shaped; peristomial dorsolateral and ventrolateral tubercles low, barely projected..................................................................... Lamprophaea Grube, 1867 reinst.

- Pharynx with upper jaw double, T-shaped, lower one a transverse plate; peristomial dorsolateral and ventrolateral tubercles projected........................................................................ Paralamprophaea n. gen.