Autolytus afer Ehlers, 1908

Nygren, Arne, 2004, Revision of Autolytinae (Syllidae: Polychaeta)., Zootaxa 680, pp. 1-314 : 159

Autolytus afer Ehlers, 1908 (Fig. 81A–B)

Autolytus afer Ehlers, 1908: 46 –47. Augener 1918: 308 –309.

Material examined. South Africa: 5 syntypes ZMB 6743, Lüderitz­Bucht.

Description. 5 fragmented syntypes in poor condition, incomplete, very fragile due to preservation in osmium. Length 1–5 mm for 15–43 chaetigers, width 0.2–0.4 mm. Preserved material brown with black pigmentation as round dots, as transverse rows on each segment, and as black spots on cirri.

Body shape, excluding parapodial lobes, cylindrical in transection, venter flattened. Body of fairly constant width. Ciliation as 1 troch per segment (Fig. 81A).

Prostomium rounded rectangular, wider than long. Four eyes, with lenses, in trapezoid arrangement, anterior pair larger. Eyes separated; absence/presence of eye spots not possible to assess. Palps in dorsal view projecting 1/3 of prostomial length, fused. Extension of nuchal epaulettes to end of chaetiger 1.

All antennae, tentacular cirri, and most cirri lost or broken. Alternation in direction of cirri not assessed. Dorsal cirri from chaetiger 3, alternate in length; short cirri equals 3/4 of body width, long cirri equals body width. Cirrophores present on tentacular cirri and all dorsal cirri. Cirrophores (Fig. 81A) and cirrostyles unequal; cirrophores and cirrostyles on short cirri 2/ 3 in length of its counterpart in long cirri; cirrophores on short cirri equal to parapodial lobes, cirrophores on long cirri longer than parapodial lobes (Fig. 81A); cirrophores shorter than cirrostyles. All appendages cylindrical.

Parapodial lobes rounded (Fig. 81A), medium to large in size. Number of aciculae not possible to assess. Chaetal fascicle with 9–12 compounds in anterior chaetiger, 3–8 in median and posterior. Compound chaetae with small distal tooth (Fig. 81B); serration present. Single thin bayonet chaeta, subdistally denticulated, beginning between chaetiger 1–13 (n=2).

Pharynx sinuation and trepan structure not possible to evaluate. Proventricle equal in length to 3 segments in chaetiger 5–7 in one small specimen. Pygidium lost.

Reproduction. See remarks.

Habitat. Not known.

Distribution. Indian Ocean. East South Africa. Known only from type locality.

Remarks. Several of Ehlers' specimens were developing stolons (Knospenanlage) behind chaetiger 13, 21 and 50, but this could not be confirmed in the present material, neither Ehlers' observations of a trepan with 10 equally large teeth, and a pharynx with 2 sinuations. If only observations made on the relation between cirrophores and cirrostyles are considered, there are several similar species including M. prolifera , M. brachycephala , M. longoprimicirrata , M. multidenticulata , and M. rangiroaensis . New material from the type locality is essential for evaluation of the status of A. afer . On the basis of Ehlers' observations on the reproductive mode, and the alternating dorsal cirrophores, it is here considered as Myrianida incertae sedis .