Polycirrus holthei Londoño-Mesa & Carerra-Parra, 2005

Glasby, Christopher J. & Hutchings, Pat, 2014, Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae), Zootaxa 3877 (1), pp. 1-117 : 61-63

Polycirrus holthei Londoño-Mesa & Carerra-Parra, 2005

Fig. 31a–e , Table 1

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

Type locality. Cancún , Mexico .

Material examined. None.

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

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 ). 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 ).

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 ).

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 ). 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 ).

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 ). 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 ) 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.

Figures

FIGURE 31. Polycirrus holthei Londoño-Mesa and Carerra-Parra. a. Entire body, dorsal view; b. Anterior, end, ventral view; c. Pinnate chaeta from segment 2. d. Uncini from segment 8. e. Uncini from segment 14. Scales e, c, d=0.02 mm, b, a=1 mm. (Modified after Londoño-Mesa and Carerra-Parra, 2005 and reproduced with permission from Zootaxa).