Autolytus syllisetosus Langerhans, 1884: 249, fig. 4 A–C.
Description. Type material do not exist; description based on one specimen. Described as follows: length 5 mm for 95 chaetigers, including 2 developing female stolons with 11, and 24 chaetigers; chaetal blades in anterior 3 chaetigers longer than usual, in chaetiger 4– 5 gradually shorter, following chaetigers with normal blades; bayonet chaetae from chaetiger 15; trepan with 40 long teeth, proventricle with 40 rows of muscle cells.
Distribution. North East Atlantic. Madeira.
Remarks. Autolytus syllisetosus is considered dubious; it has never been recorded after its original description, and Langerhans only found one specimen. The chaetal blades normally show some length variation in autolytines, anterior chaetigers and more ventrally positioned chaetae slightly longer, although not as pronounced as described in A. syllisetosus.