Polycirrus mexicanus ( Rioja, 1947 )

Glasby, Christopher J. & Hutchings, Pat, 2014, Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae), Zootaxa 3877 (1), pp. 1-117 : 73-74

Polycirrus mexicanus ( Rioja, 1947)

Fig. 39a–h

Anisocirrus mexicanus Rioja, 1947 , 210–212, figs 18–25.

Type locality. Western Mexico .

Material examined. None.

Description. Coded from original description.

Venter anteriorly with mid-ventral groove and discrete ventro-lateral pads; pads more-or-less smooth. Midventral groove from segment 3 ( Fig. 39a ).

Buccal tentacles two types: (1) leaf-shaped, deeply furrowed and (2) cylindrical, uniformly thin and weakly grooved, both arising at junction between prostomium and upper lip. Upper lip trefoiled, small wing-like lobes laterally. Outer lower lip flat, shield-like, oblong, wider than long, with antero-median recess.

Notochaetigerous segments 14–18, extending to segments 16–20. Notopodia more-or-less rectangular, prechaetal lobe low, postchaetal lobe digitiform, postchaetal lobe cirriform, longer than prechaetal ( Fig. 39b ). Notochaetae within a chaetiger of two types, pinnate, posteriorly same form as those anteriorly; secondary notochaetae in all chaetigers smooth, narrowly winged, uniformly tapered ( Fig. 39c, d ). Neurochaetae probably beginning after last notochaetigerous segment (see Comments). Uncini with short neck and straight to convex base (Type 1), single tooth teeth above main fang, subrostral process present as low, rounded protuberance.

Comments. While the original description states that the type is held in the collections of the Institute of Biology, attempts to locate it have been unsuccesful. We believe that these collections were transferred at some point to the National Museum in Mexico City, which was damaged during an earthquake .

Rioja does not state in the original description where the neuropodia start in relation to the notopodia. Almost certainly they begin after the last notochaetigerous segment as this would account for Rioja’s placement in the genus Anisocirrus , which is defined by its lack of neurochaetae on the ‘thorax’. However, whether they begin one or two segments after the last notochaetigerous segment or well after this (couplet 1, key) is unknown. Therefore, this species was included twice in the key.

Figures

FIGURE 39. Polycirrus mexicanus (Rioja). a. Anterior body, ventral view. b. Notopodium from unknown chaetiger c, d. e. Portion of pinnate notochaeta. Notochaetae. f. Uncinus. g. Bidentate hooks. h. Posterior bidentate hooks. (After Rioja, 1947; no scales or chaetiger number on original).