Levidorum Hartman 1967

Levidorum Hartman, 1967

Levidorum scotarium Hartman, 1967: 84, pl. 28.

Linnean name definition. Type species Levidorum scotarium Hartman, 1967 by monotypy.

Node­based name definition. Levidorum refers to the least inclusive clade comprising L. scotarium Hartman, 1967 and L. hartmanae Perkins, 1987.

Apomorphies. Clade supported by 6 morphological apomorphies (Fig. 4): 1) nuchal epaulettes absent (character 7), other most parsimonious reconstructions (MPRs) possible; 2–5) median antenna, lateral antennae, tentacular cirri, and first dorsal cirri absent (characters 11–14); 6) number of teeth equals 5 (character 40), character state change is a parallelism.

General description.

Atokous form. Length 3.9–12 mm for 37–54 chaetigers; width measured at level of proventricle, 0.3–1.5 mm. Body shape cylindrical in transection, venter flattened; body width fairly constant with tapering end, in L. hartmanae body swollen between chaetiger 2–15. Ciliation absent in L. pori (not known otherwise). Prostomium rounded rectangular, wider than long. Prostomium may dorsally have a transverse furrow, more or less distinct. Perkins (1987) interpret the anterior end differently. What is here considered as the posterior part of the prostomium is believed to be an additional peristomial segment. Eyes absent, or present as four eyes, with lenses, anterior or posterior pair larger. Palps may be present, basally fused, or absent. Nuchal epaulettes absent.

All appendages absent. Parapodial lobes very small, rounded to conical. All chaetae simple, knob­like. Bayonet chaetae not found, possibly absent.

Pharynx with 1 sinuation anterior and lateral to proventricle. Trepan with 5 equal, and long teeth, arranged in 1 ring. Basal ring present; infradental spines absent. Proventricle with varying number of rows of square shaped muscle cells (unknown in L. scotarium).

Reproduction. Schizogamous reproduction by anterior scissiparity behind chaetiger 13 or 14 (unknown in L. scotarium and L. pori).

Epitokes. Fully developed stolons not examined, but see also description of Autolytus pacificus Treadwell, 1943 (Autolytinae incertae sedis).