Raphidrilus

Magalhães, Wagner F., Bailey, Julie H., Brock, - & Davenport, Jennifer S., 2011, On the genus Raphidrilus Monticelli, 1910 (Polychaeta: Ctenodrilidae) with description of two new species, Zootaxa 2804, pp. 1-14 : 3

Key to species of Raphidrilus (After Monticelli, 1910b)

1A Prostomium with a pair of nuchal organs only; parapodia without sensorial tufts; dorsal anal aperture.................. 2

1B Prostomium with scattered sensorial tufts in addition to a pair of nuchal organs; parapodia with sensorial tufts; terminal anal aperture............................................................. Raphidrilus sp. sensu Qian & Chia, 1989

2A Three to six capillaries in thoracic chaetigers; abdominal chaetigers 1.5–4 times longer than wide and without sub–annulations; heart body extends posteriorly more than one chaetiger.................................. Raphidrilus harperi sp. nov.

2B No more than four capillaries in thoracic chaetigers; abdominal chaetigers 1–2 times as long as wide; heart body extends anteriorly or restricted to one chaetiger........................................................................ 3

3A One or two dorsally biannulated anterior achaetous segment; heart body anteriorly directed to the middle of chaetiger 3; distance between the insertion point of two capillary fibrils along the capillary chaetae approximately the same as half the width of a single fibril............................................................ .. Raphidrilus hawaiiensis sp. nov.

3B Only one dorsally biannulated anterior achaetous segment; heart body restricted to chaetiger 4; distance between the insertion point of two capillary fibrils along the capillary chaetae approximately the same as the width of a single fibril................................................................................. Raphidrilus nemasoma Monticelli, 1910a