Chone Krøyer, 1856 Restricted

Tovar-Hernández, María Ana & Sosa-Rodríguez, Teresa, 2006, Redescription of Chone infundibuliformis Krøyer, 1856 (Polychaeta: Sabellidae) and histology of the branchial crown appendages, collar and glandular ridge, Zootaxa 1115, pp. 31-59 : 36

Chone Krøyer, 1856 Restricted

Chone Krøyer, 1856 , p. 13.— Sars, 1862, p. 119.— Malmgren, 1866, p. 404.— Langerhans, 1881, p. 111.— Hofsommer, 1913, p. 332.— McIntosh, 1923, p. 287.— Fauvel, 1927, p. 334.— Day, 1967, p. 776.— Banse, 1972, p 460.— Fitzhugh, 1989, p. 67.— Giangrande, 1992, p. 518.

Parachonia Kinberg, 1867 , p. 355.

Dialychone Claparède, 1870 , p.170.

Megachone Johnson, 1901 , p. 430.

Metachone Bush in Moore, 1904, p. 190.

Type species: Chone infundibuliformis Krøyer, 1856 .

Definition: Branchial lobes fused dorsally. Radiolar skeleton with two rows of cells. Palmate membrane and radiolar flanges present. Dorsal lips broadly rounded, as long as wide, without mid­rib; vascularized by plexus of small blood vessels derived from basal branchial blood vessels; dorsal lips with hyaline cartilage, but without branchial skeleton extensions. Ventral lips present, broadly rounded. Dorsal and ventral pinnular appendages present. Anterior margin of anterior peristomial ring with narrow ventral lobe. Posterior peristomial ring collar present. Glandular ridge on chaetiger 2. Ventral shields absent. Notopodia in chaetiger 1 with two groups of elongate, narrowly hooded chaetae in Cshaped arrangement. Notopodia in chaetigers 2–8 with superior group of chaetae in two irregular rows, all elongate, narrowly hooded; inferior group with one anterior row of short bayonet chaetae, two posterior rows with symmetrical, mucronate (or with very fine hairs instead) paleate chaetae. Thoracic neuropodia bearing acicular uncini with teeth above main fang unequal in size, median tooth of basal row enlarged, hood present, handles long. Anterior abdominal segments with two transverse rows of elongate, narrowly hooded chaetae, chaetae from the anterior row shorter than chaetae in posterior row; uncini with well developed rectangular breast, handles absent, main fang well developed, few rows of small teeth covering one half (or less) of the main fang length; intrafascicular variation: older uncini, located dorsalmost in torus, smallest in size, younger uncini, located ventralmost in torus, biggest in size. Posterior abdominal segments with very elongate, narrowly hooded chaetae; uncini shape and intrafascicular variation similar to those in anterior abdominal segments.

Remarks: The following genera have been placed into synonymy with Chone : Parachonia , by Johansson (1927); Megachone , by Banse (1972); Metachone , by Fauvel (1927); Dialychone , by Fitzhugh (1989). Parachonia letterstedti Kinberg, 1867 [SMNH 576, holotype], Megachone aurantiaca Johnson, 1901 [MCZ 1933, holotype], and Metachone mollis Bush in Moore, 1904 [YPM 2793, holotype] agree in every respect with the above definition of the genus. Dialychone was synonymized with Chone by Fitzhugh (1989) because of the presence or absence of the palmate membrane is a character used to distinguish species rather than genera. Although no type material is available for this species, Knight­Jones et al. (1991), Giangrande (1992), and Fitzhugh (1989) reviewed topotype material of Dialychone acustica Claparède, 1870 , indicating a low web extends for about a quarter of the branchial crown length.