Chone rosea Hartmann-Schröder, 1965

Tovar-Hernández, María Ana, 2007, On some species of Chone Krøyer, 1856 (Polychaeta: Sabellidae) from world-wide localities, Zootaxa 1518, pp. 31-68 : 55-56

Chone rosea Hartmann-Schröder, 1965

Figure 14

Chone rosea Hartmann-Schröder, 1965: 276 –278, Figs 279–280.

Material examined. Type material. off South Chile [ ZMH P–15202, holotype], Exp. Mar Chile I, March 1960.

Additional material. Chone bimaculata Banse and Nichols, 1968 [ USNM 36280, paratypes]. Chone duneri Malmgren, 1867 [ ZMUC POL –1755, topotypes]. Chone dunerificta Tovar-Hernández et al. (2007) [ MNCN 16.01/7369, holotype].

Description. Colour, body shape, and size. Holotype complete. Body cream-coloured. Trunk cylindrical. Body length 17 mm, width 2 mm. Tube unknown.

Branchial lobes and branchial crown. Insertion of the branchial crown not exposed beyond collar ( Figs 14 A–C). Branchial crown length: 19 mm. Radioles: 9 pairs. Median pinnules longer than more proximal pinnules. Radiolar tips extra long (7 mm) ( Figs 14 A, G). Palmate membrane extends about half the length of the branchial crown. Lateral flanges broad ( Fig. 14 G). Dorsal lips broadly rounded, as long as wide, without midrib. Dorsal pinnular appendages: two short pairs united by a membrane. Ventral lips rounded, as long as wide, about half of the dorsal lips length. Ventral radiolar appendages: three pairs, the first about one quarter the length of the branchial crown, the rest about a half of the branchial crown.

Peristomium . Anterior peristomial ring lobe not exposed beyond collar ( Fig. 14 B), distally entire, triangular. Posterior peristomial ring collar: antero-dorsal, ventral and lateral margins entire, ventral margin slightly higher than dorsal ( Figs 14 A–C); the entire length of mid-dorsal collar margins is overlapped ( Fig. 14 C). Dorsal pockets not developed. Ventral shield of collar sunglasses-shaped, swollen ( Fig. 14 B). Ratio of posterior peristomial ring collar length versus chaetiger 2 length, in lateral view: 2:1.

Thorax. Chaetiger 1: two groups of elongate, narrowly hooded chaetae. Chaetigers 2 to 8: Notopodia: superior group with two irregular rows of elongate narrowly hooded chaetae; inferior group with one anterior row of bayonet chaetae; two posterior rows with paleate chaetae with short mucro ( Fig. 14 D). Neuropodia: acicular uncini distributed as a regular row, second tooth enlarged (not illustrated), located in the midline, dentition covering one quarter the length of the main fang ( Fig. 14 E). Glandular ridge on chaetiger 2 narrow.

Abdomen. Abdominal segments: 35. Anterior segments: two transverse rows of elongate, narrowly hooded chaetae, upper row chaetae half as long as lower row ones; uncini with the main fang surmounted by four rows of teeth in frontal view, occupying less than half of the main fang length, main fang not extending beyond breast ( Fig. 14 H). Posterior segments: very elongate, narrowly hooded chaetae, 25% longer than those of anterior segments; uncini similar to those in anterior abdomen, but smaller ( Fig. 14 I). Pygidium with rounded posterior margin ( Fig. 14 A).

Gametes. Spermatozoa with barrel-shaped nucleus, mushroom-shaped acrosome and two rounded mitochondria ( Fig. 14 F).

Methyl green staining. Ventrally body stains uniformly, except for the basal half of the collar that is less coloured ( Figs 14 B); dorsally body stains uniformly, except for the faecal groove ( Fig. 14 C).

Remarks. Chone rosea is unique by having a long collar; the ventral shield of collar is remarkable because it is sun glasses-shaped ( Table 2 ); the mid-dorsal collar margins overlap and extremely long radiolar tips. Other species with extra long radiolar tips (but shorter than C. rosea ) are C. duneri , C. dunerificta and C. bimaculata ; but the anterior peristomial ring lobe is triangular, not exposed beyond collar in C. rosea (bilobed, exposed in all others).

Figures

FIGURE 14. Chone rosea. (A) Body, lateral view; (B) anterior end, ventral view; (C) same, dorsal view; (D) paleate chaeta; (E) thoracic uncinus; (F) spermatozoa; (G) radiolar tip; (H) anterior abdominal uncinus; (I) posterior abdominal uncinus. (B – C) Methyl green staining. (A – I) [ZMH P – 1502, holotype].