Myrianida tereseta Hoagland, 1920

Nygren, Arne, 2004, Revision of Autolytinae (Syllidae: Polychaeta)., Zootaxa 680, pp. 1-314 : 114

Myrianida tereseta Hoagland, 1920 (Fig. 54 A–E)

Myrianida tereseta Hoagland, 1920: 603 –604, pl. 46, fig. 1–3.

Material examined. Philippine: holotype USNM 18942 (female stolon), Ticao Island, San Miguel Harbor, Philippine Expedition 1907–1910.

Description. Type incomplete in several parts. Length c. 15 mm for 6+35+70 chaetigers, width 0.4 mm in region a excluding parapodial lobes, width in region b 1 mm including parapodial lobes. Preserved material yellowish, without colour markings (Fig. 54C); body filled with eggs. Ciliation not possible to assess.

Prostomium wider than long, anterior margin concave (Fig. 54A, B). Four eyes, with lenses, situated on ventral and dorsal side of prostomium; ventral pair much larger (Fig. 54A, B). Palps absent. Nuchal epaulettes reaching beginning of chaetiger 1.

Median and lateral antennae, inserted on anterior margin of prostomium (Fig. 54A), equal in length to prostomial width; median antenna slightly longer. Tentacular cirri 2 pairs (Fig. 54B); dorsal pair as long as 1/2 prostomial width, ventral pair 1/3 as long as dorsal. First dorsal cirri, equal in length to antennae, longer than following dorsal cirri; achaetous knobs present (Fig. 54B). Second dorsal cirri situated above first chaetigerous lobes. Cirri in region a reciprocally equal, in length equal to body width; cirri in region b equal in length to cirri in region a, without any alternation in length (Fig. 54C); cirri in region c diminishing regularly towards the end. Cirrophores absent.

Parapodia in region a, and c with rounded conical neuropodial lobes, of small to medium size; parapodia in region b, slightly larger than in region a, with additional notopodial lobes. Single neuropodial acicula in all chaetigers; 2 anterodorsal and 4 thick and 4 thin posteroventral notoaciculae in region b. Neuropodial chaetal fascicle with c. 10 compounds in region a and b, 5–7 in region c. Compound chaetae with small distal tooth (Fig. 54D); serration present. Thin bayonet chaetae (Fig. 54E), subdistally denticulated, present in posterior chaetigers. Notopodial chaetal fascicle with 15–20 swimming chaetae. Posterior part lost.

Distribution. Central Pacific. Philippines. Only known from type specimen.

Remarks. It is not understood on what basis M. tereseta was referred to Myrianida , as all the appendages are cylindrical. In any case, M. tereseta is another stolon like A. obliquatus , and A. rostripalpus , with achaetous knobs, 6 chaetigers in region a, in combination with a thin bayonet chaetae. However, the distal tooth of the compound chaetae in M. tereseta is small, while large in A. obliquatus and A. rostripalpus . For the same reasons as discussed for A. obliquatus , and A. rostripalpus , M. tereseta is considered as Procerini incertae sedis .