Key to Pilargidae genera found in Brazilian waters

1. Body dorsoventrally flattened with papillae or verrucae on surface.............................................. 2

- Body cylindrical (may be anteriorly inflated), often long and springy (nematode-like), with surface smooth.............. 6

2. Notochaetae present................................................................................... 3

- Notochaetae absent............................................................... Pilargis Saint-Joseph, 1899

3. Notochaetae robust, spine-like................................................... Glyphohesione Friedrich, 1950

- Notochaetae otherwise................................................................................. 4

4. Tentacular cirri reduced or shorter than half of peristomium width; ventral cirri from chaetiger 1–3 to last chaetiger....... 5

- Tentacular cirri as long as or longer than peristomium width; ventral cirri present from first chaetiger to last chaetiger (but may be absent on chaetiger 2)............................................................. Sigambra Müller, 1858

5. Body surface papillate or with verrucae, parapodia biramous, pygidium tapered with two cirri..................................................................................................... Ancistrosyllis McIntosh, 1878

- Body surface smooth, parapodia inconspicuous, pygidium bilobed without cirri.................... Cabira Webster, 1879

6. Two pairs of tentacular cirri, neurochaetae include acicular spines or spines and capillaries........................... 7

- Tentacular cirri absent, neurochaetae capillaries only..................................... Hermundura Müller, 1858

7. Palps fused dorsally, or nearly fused, with small palpostyles ventrolaterally inserted.............. Litocorsa Pearson, 1970

- Palps biarticulated with a small ventral papilla associated with palpostyle.................... Synelmis Chamberlin, 1919