Chone gracilis Moore, 1906

Tovar-Hernández, María Ana, 2007, Revision of Chone Krøyer, 1856 (Polychaeta: Sabellidae) from North America and descriptions of four new species, Journal of Natural History 41 (9 - 12), pp. 511-566: 534-536

publication ID 10.1080/00222930701250912

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Chone gracilis Moore, 1906


Chone gracilis Moore, 1906  

( Figure 8 View Figure 8 )

Chone gracilis Moore 1906, p 257   –259, Plate 12, Figures 62–66; Berkeley and Berkeley 1952, p 123 –124, Figure 254; Hartman 1969, p 665; Fauchald 1972, p 326 –327.

Material examined

Type material. Alaska [ USNM 5513 View Materials (holotype), ANSP AD 2208 View Materials (one paratype), ANSP 1- 24 View Materials (one paratype), Alitak Bay, Kodiak Island , Sta. 4274, 1903, 4–56.3 m]   .

Non-type material. Alaska [ USNM 40723 View Materials ], Pavlov Bay , Ms. Stranger, coll. E. and C. Berkeley (3)   . Oregon [ LACM-AHF], 000002-62, 44 ° 33.59N, 125 ° 14.69W, 2000 m, Cruise 6207A, AD6, 6 July 1972 (1) GoogleMaps   ; 000009-25 (1); 000007-12 (4).

Description (based on holotype, in parentheses variation observed in paratypes)

Colour, body shape, and size. Body cream coloured (brown in USNM 40723) with an iridescent epicuticle. Trunk cylindrical. Holotype complete, but pygidium and some radioles are broken, branchial crown almost separate from the body. Body length 21 mm (5–12 mm), width 1.5 mm (0.5–1.5). Tube hyaline.

Branchial lobes and branchial crown. Insertion of the branchial lobes partially exposed dorsally beyond collar ( Figure 8A View Figure 8 ). Branchial crown length 11 mm (1.75–3.5). Radioles: nine (seven) pairs. Radioles with median pinnules three times longer than more proximal pinnules. Radiolar tips medium-sized ( Figure 8D, H View Figure 8 ). The palmate membrane extends to three-quarters the length of branchial crown. Lateral flanges broad ( Figure 8D–H View Figure 8 ). Dorsal lips (dl) broad basally, triangular towards tip, erect, without mid-rib ( Figure 8I View Figure 8 ). Dorsal pinnular appendages: (six pairs). Ventral lips (vl) rounded, small, as long as one-quarter the length of dorsal lips ( Figure 8I View Figure 8 ). Ventral radiolar appendages: (three pairs).

Peristomium   . Anterior peristomial ring lobe not exposed beyond collar, distally entire, triangular. Posterior peristomial ring collar: antero-dorsal margin entire ( Figure 8A View Figure 8 ); lateral margins entire ( Figure 8C–F View Figure 8 ); ventral margin incised in holotype ( Figure 8B View Figure 8 ), entire in paratype ( Figure 8E View Figure 8 ) and higher than dorsal ( Figure 8C, F View Figure 8 ); entire length of mid-dorsal collar margins forms a broad gap; broad faecal groove ( Figure 8A View Figure 8 ); dorsal pockets well developed. Ventral shield of collar swollen, horseshoe-shaped, two times wider than long ( Figure 8B, E View Figure 8 ). Ratio of posterior peristomial ring collar length versus chaetiger 2 length, in lateral view: 2:1.

Thorax. Chaetiger 1: two groups of nine elongate, narrowly hooded chaetae. Chaetigers 2– 8: notopodia—two rows of nine elongate, narrowly hooded chaetae; one anterior row with four to five bayonet chaetae ( Figure 8K View Figure 8 ); two posterior rows with five symmetrical, paleate chaetae with short mucro ( Figure 8L View Figure 8 ); neuropodia—two irregular rows (one row) of 19 (13) acicular uncini per torus, facing in the same direction, the oldest upper parts of the tori have only one row (one-quarter of the torus length), main fang surmounted by four rows of teeth, second tooth enlarged, located in the midline, dentition occupying a quarter the length of main fang ( Figure 8J View Figure 8 ). Pre- and post-chaetal lobes well developed. Glandular ridge on chaetiger 2: narrow.

Abdomen. Abdominal segments: (24–43). Anterior segments: two transverse rows of very elongate, narrowly hooded chaetae; uncini with the main faing surmounted by three rows of teeth occupying one-half the length of main fang, main fang not extending beyond breast, breast rectangular ( Figure 8M View Figure 8 ). Posterior segments: very elongate, narrowly hooded chaetae; uncini similar to those in anterior abdomen, but larger ( Figure 8N View Figure 8 ). Pygidium with rounded posterior margin ( Figure 8G View Figure 8 ).

Gametes. Holotype female with oocytes in thorax and abdomen; paratype immature.

Methyl green staining. Anterior end of the ventral shield of collar not coloured, posterior end dark ( Figure 8A View Figure 8 ). The epidermis is completely glandular (looks like a mat) and stains uniformly in thorax and abdomen, dorsally and ventrally ( Figure 8E–G View Figure 8 ).


Chone gracilis Moore, 1906   and Chone gracilis Hofsommer, 1913   described from the Kiel Canal (Baltic Sea) are homonyms. The species of Moore is a senior homonym [according to the Principle of Homonym (Article 52.2) and the Principle of Priority (Article 52.3) from the International Commission on Zoological Nomenclature 2000]. It may be used as a valid name. The holotype of Chone gracilis   has the ventral margin of the collar incised probably, due to a regeneration process. However, in paratype and additional material it is entire. Deep-water specimens from Oregon have abdominal elongate narrowly hooded chaetae, extremely long. Chone gracilis   is unique among the species of Chone   distributed in North American waters in having medium-length radiolar tips. Among species in Group I, Chone gracilis   and C. infundibuliformis   have a short mucro; however, the ventral margin of the collar is higher than dorsal margin in C. gracilis   , and slightly higher in C. infundibuliformis   .


Academy of Natural Sciences of Philadelphia


Smithsonian Institution, National Museum of Natural History














Chone gracilis Moore, 1906

Tovar-Hernández, María Ana 2007

Chone gracilis

Fauchald K 1972: 326
Hartman O 1969: 665
Berkeley E & Berkeley C 1952: 123
Moore JP 1906: 257