Polycirrus medusa Grube, 1850

Glasby, Christopher J. & Hutchings, Pat, 2014, Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae), Zootaxa 3877 (1), pp. 1-117 : 71

Polycirrus medusa Grube, 1850

Figs 37a, b ; 38a–f

Polycirrus medusa Grube, 1850: 330 ; 1855: 120–121.

Type locality. Anse du Rouet, just west of Marseille , France (neotype) .

Material examined. NEOTYPE: MNHN 1545 , France, Mediterranean coast, Anse du Rouet, just west of Marseille, France, dead Posidonia beds shallow subtidal, 43°19ʹ59ʺ N, 5°09ʹ10ʺ E, Site E. 3, M.C. 4 (I), 1.8 m, coll. A. Willsie, 9.ix.1982.

Description. Fragile, body wall slightly damaged at mid-body level ( Fig. 34a ).

Dorsum anteriorly tessellated. Venter anteriorly with mid-ventral groove and discrete ventro-lateral pads; pads more-or-less smooth, extending from segment 3 to 9. Mid-ventral groove from segment 3 ( Fig. 37b ). Mature female.

Buccal tentacles missing, arising at junction between prostomium and upper lip. Prostomial ridge slightly curved, extending laterally along anterodorsal base of upper lip. Upper lip trefoiled, small wing-like lobes laterally, margin of medial lobe thin, convoluted; oral surface glandular and ciliated. Inner lower lip smooth, oblong, rounded, half size of outer lip; outer region flat, shield-like, subtriangular and pointing toward mouth, smooth, extending posteriorly to segment 3. Achaetous segments visible dorsally but obscured by expanded outer lower lip ventrally.

Notochaetigerous segments 12, extending to segment 14. Notopodia more-or-less rectangular, prechaetal lobe low, postchaetal lobe digitiform, longer than prechaetal ( Fig. 38a, b ). Notochaetae within a chaetiger consisting of two types (chaetigers 3 and 10 examined): (1) smooth, narrowly winged, worn tips slightly hirsute, uniformly tapered, posteriorly same form as those anteriorly; (2) secondary notochaetae in all chaetigers pinnate ( Fig. 38e,f ). Neurochaetae beginning on segment 15; 53 uncini per row on mid-posterior body neuropodium. Neuropodial tori erect pinnules, similar along body. Uncini with short neck and straight to convex base (Type 1), teeth above main fang arranged in single transverse series, enlarged median tooth above main fang present, subrostral process present as low protuberance ( Fig. 38c,d ).

Nephridial papillae present, globular. Pre-gular membrane nephridial papillae absent. Post-gular membrane nephridial papillae present, extending from segment 5 to 8; situated at ventral base of notopodia. Pygidium smooth ring.

Comments. Grube’s (1850) description of the species is very brief (two lines); in a later paper ( Grube, 1855) he gives a more comprehensive (for the time) account of the species, but it is inadequate by today’s standards to differentiate the species from several other Polycirrus species. In this latter paper he also refers to the type locality as Villa Franca (near Nice, France). Further, a possible holotype was in the collection of the Museum für Naturkunde der Humboldt-Universitat, Belin, but has been lost ( Holthe, 1986b). Thus, designation of a neotype was deemed necessary. We have designated a neotype of P. medusa as the type of Polycirrus by monotypy from Anse du Rouet, just west of Marseille collected from a similar habitat. The neotype shows some resemblance to the description of material from the North Sea identified as P. medusa by Holthe (1986b), but it is not conspecific as he refers only to plumose (=pinnate) notochaetae unlike the neotype which has both smooth and pinnate types in the same notopodium. The identity of Holthe’s material is uncertain given that he does not specify material examined and that several similar Polycirrus species exist in the region.

Figures

FIGURE 34. Polycirrus luminosus Verrill. a–c. Non type specimen YPM 1311a. Notochaeta illustrated at x40 and x100 from notopodium, chaetiger 25. b. Frontal view of uncinus from chaetiger 16. c. Lateral view of uncinus from chaetiger 25.

FIGURE 37. Polycirrus medusa Grube. Neotype MNHN 1545, a.entire body, dorsal view; b.entire body, ventral view.

FIGURE 38. Polycirrus medusa Grube. Neotype MNHN 1545. a. parapodium, chaetiger 3. b, parapodium, chaetiger 10. c, uncini, frontal view, mid-posterior body chaetiger. d, uncini, side view, mid-posterior body chaetiger. e. chaetae, chaetiger 3. f. chaetae, chaetiger 10.