Polycirrus holthei Londoño-Mesa & Carerra-Parra, 2005

Polycirrus holthei Londoño-Mesa & Carerra-Parra, 2005 View in CoL

Fig. 31a–e View FIGURE 31 , Table 1 View TABLE 1

Polycirrus holthei Londoño-Mesa & Carerra-Parra, 2005: 4–6 View in CoL , fig. 1D–H.

Type locality. Cancún , Mexico .

Material examined. None.

Type material. HOLOTYPE: ECOSUR 0054 View Materials , Mexico, Cancún , Punta Nizuc, 21°02′11.7′′ N, 86°46′44.2′′ W, coll. 10.ii.2001, 2 m, in coralline rock. GoogleMaps

Description. Based on type description. Holotype complete with 42 segments, 6.5 mm long, 1.1 mm wide; paratypes with up to 46 segments. Body transparent when preserved.

Dorsum anteriorly smooth ( Fig. 31a View FIGURE 31 ). Venter anteriorly with mid-ventral groove and discrete ventro-lateral pads (visible only with stain); pads more-or-less smooth, extending from segment 2 to 6–7. Mid-ventral groove from segment 3 ( Fig. 31b View FIGURE 31 ).

Buccal tentacles two types: (1) cylindrical, thickened distally, distinctly grooved and (2) cylindrical, uniformly thin, weakly grooved. Prostomial ridge distinctly curved, extending laterally along anterodorsal base of upper lip. Upper lip trefoiled, small wing-like, clover-shaped lobes laterally, margin of medial lobe straight and narrow. Outer lower lip flat, shield-like, oblong, wider than long, ridged and grooved, extending posteriorly to segment 2. Achaetous segments visible dorsally but obscured ventrally ( Fig. 31a, b View FIGURE 31 ).

Notochaetigerous segments 10–13, extending to segments 12–15. Notopodia digitiform, pointed. Notochaetae within a chaetiger one type, two distinct lengths, pinnate, posteriorly same form as those anteriorly ( Fig. 31c View FIGURE 31 ). Neurochaetae beginning on segment 6. Uncini with long neck and concave base ( Type 2), anterior ones with almost flat base and smaller, teeth above main fang arranged in double or triple transverse series (anteriorly MF:1:3-4:5-6, but see comments; posteriorly MF:1:1) enlarged median tooth above main fang present, subrostral process absent ( Fig. 31d,e View FIGURE 31 ).

Nephridial papillae present, spherical. Pre-gular membrane nephridial papillae absent. Post-gular membrane nephridial papillae present, extending from segment 5 to 11–13; situated at posteroventral base of notopodia ( Fig. 31a View FIGURE 31 ). Pygidium papillated ring with nine short papillae.

Comments. The dental formula for the thoracic neurochaetae provided by Londoño-Mesa & Carerra-Parra (2005) suggests three rows of teeth above the main fang, yet their figure ( Fig. 31e View FIGURE 31 ) shows only two rows, at least in the way that we interpet a row (successive curved lines of teeth). Therefore using our definition, the dental formula would be MF:1:8–10. Another discrepancy between the description and the figures is in regard to the position of the nephridial papillae. Londoño-Mesa & Carerra-Parra (2005) state that they are posterior to the notopodia, but figure 31a, b clearly show them to be anterior to the notopodia.