Paradialychone cincta ( Zachs, 1933 ) Zachs, 1933

Nishi, Eijiroh, Tanaka, Katsuhiko, Tovar-Hernández, María Ana & Giangrande, Adriana, 2009, Dialychone, Jasmineira and Paradialychone (Annelida: Polychaeta: Sabellidae) from Japan and adjacent waters, including four new species descriptions, Zootaxa 2167, pp. 1-24: 3-7

publication ID

http://doi.org/ 10.5281/zenodo.189112

DOI

http://doi.org/10.5281/zenodo.5233999

persistent identifier

http://treatment.plazi.org/id/03B7C922-FFFA-1927-FF2A-5204FF4DFC93

treatment provided by

Plazi

scientific name

Paradialychone cincta ( Zachs, 1933 )
status

new combination

Paradialychone cincta ( Zachs, 1933)   new combination

Figures 2–3 View FIGURE 2 View FIGURE 3

Chone cincta Zachs, 1933: 135   .

Material examined. CBM –ZW 1018, Ariake Sound, Kyushu, St. AD 20, sandy mud, 20m, 17 September, 2005, by dredge, by K. Mori. CBM-ZW 1019, Ariake Sound, Kyushu, St. AF 8 D, sandy mud, 27m, by dredge, 12 November, by K. Mori. KMNH-IvR- 500.421, Ariake Sound, Kyushu, St. AF 7 D, 18m, sandy mud, by dredge, 12 November, 2005, dredge, K. Mori. ECOSUR, Ariake Sound, Kyushu, St. AD 20 D, sandy mud, 20m, 17 September, 2005, by grab-sampler, by K. Mori. SAMA E 3725. Ariake Sound, Kyushu, St. AD 19 D, shell stones, 35m, by dredge, 17 September, 2005, by K. Mori. ZMUC-POL- 2061, Ariake Sound, Kyushu, St. AH 13 D, sandy mud, 43m, by dredge, 11 November, 2005, K. Mori. KMNH –Iv.R- 500.422, Ariake Sound, Kyushu, St. AE 20 D, sandy bottom, 20m, by dredge, 17 September, 2005, K. Mori. MNHN PNT 10 - Ariake Sound, Kyushu, St. AD 20, sandy mud, 20m, 17 September, 2005, by dredge, by K. Mori. NHM-ANEA- 2009.17, Ariake Sound, Kyushu, St. AF 7 D, sandy mud bottom, 18m, 12 November, 2005, by K. Mori. BPBM- R 3394, Ariake Sound, Kyushu, St. AD 20, sandy mud, 20m, 17 September, 2005, by dredge, by K. Mori. SMF 18133 View Materials , Ariake Sound, Kyushu, St. AD 20, sandy mud, 20m, 17 September, 2005, by dredge, by K. Mori. USNM 1123952, Ariake Sound, Kyushu, St. AD 20, sandy mud, 20m, 17 September, 2005, by dredge, by K. Mori. MBM 119725, Ariake Sound, Kyushu, St. AD 20, sandy mud, 20m, 17 September, 2005, by dredge, by K. Mori. CMNH-ZW 1689-1692, Ariake Sound, Kyushu, St. AG 11 D, sandy mud, 26m, 18 September, 2005, by dredge, by K. Mori.

Description. Body cream colored. Body cylindrical. Posterior abdomen compressed dorso-ventrally. Body length 10–12 mm, width 1.0– 1.2 mm. Tubes made of mucus-like material, soft and thin. Insertion of branchial lobes exposed beyond collar in dorsal view ( Figure 3 View FIGURE 3 A). Branchial crown length 4.0–5.0 mm. Radioles: 8–10 pairs. Radiolar tips filiform, slender, long (tip 1.4–1.5 mm versus 4.2 mm crown length). Radiolar skeleton with two rows of cells. Distal pinnules longer than more proximal pinnules. Palmate membrane extends for about one half of branchial crown length. Lateral flanges broad along the outer edges of radioles. Dorsal lips five times longer than wide, without mid-rib ( Figure 3 View FIGURE 3 C). One pair of dorsal pinnular appendages united to each other by palmate membrane, shorter than dorsal lip length. Ventral lips rounded, about one-quarter length of dorsal lips. Ventral radiolar appendages long, about one-half length of crown ( Figure 3 View FIGURE 3 C). Anterior peristomial ring lobe triangular, not extended beyond collar ( Figure 3 View FIGURE 3 B). Ventral margin of collar entire, triangular, higher than dorsal and lateral margins ( Figures 2 View FIGURE 2 A–B, 3 A–B). Mid-dorsal collar margin forms a narrow gap ( Figures 2 View FIGURE 2 A, 3 A). Dorsal pockets of collar not developed ( Figures 2 View FIGURE 2 A, 3 A). Ventral shield of collar circular, poorly discernible, glandular pattern laterally extending towards dorsal side ( Figure 2 View FIGURE 2 A–B). Distal part above ventral shield not stained by methyl green ( Figures 2 View FIGURE 2 A–B, 3 A–B). Ratio of posterior peristomial ring collar length versus chaetiger 2 length, in lateral view = 1.5: 1. Notopodia of chaetiger 1 with two groups of elongate, narrowly hooded chaetae. Notopodia of chaetigers 2–8 with two irregular rows of elongate, narrowly hooded chaetae ( Figure 3 View FIGURE 3 F), one anterior row with bayonet chaetae, and two posterior rows with symmetrical, paleate chaetae with short mucros ( Figures 2 View FIGURE 2 C, 3 D). Neuropodia of chaetigers 2–8 with one row of acicular uncini (ca. 15 in number) with main fang surmounted by 3–4 rows of teeth unequal in size, occupying half the length of main fang ( Figure 2 View FIGURE 2 D–E). Glandular girdle on chaetiger 2 clear, near anterior segment margin dorsally and ventrally; but laterally near posterior segment margin ( Figure 2 View FIGURE 2 A–B). Posterior end of abdomen with a dorsoventral pre-pygidial depression. Abdominal segments: 42–46. Anterior segments with two rows of 6–7 elongate, narrowly hooded chaetae, chaetae from upper half as long as chaetae in posterior row; 10–15 uncini per torus with main fang surmounted by 3–4 rows of unequal size teeth ( Figure 2 View FIGURE 2 F), extending one- half length of main fang, older (dorsal most) uncini smaller than younger uncini (ventral most), breast rectangular ( Figure 3 View FIGURE 3 H). Posterior segments with one or two very elongate, narrowly hooded chaetae, ca. twice longer than in anterior segments; 10–12 uncini per torus, rasp-shaped with 7–8 rows of equal-size teeth, occupying more than three quarters of main fang length ( Figure 2 View FIGURE 2 G). Pygidium with rounded posterior margin.

Glandular pattern: Mid-ventral area of collar deeply stained all around with methyl green, anterior and posterior margins with less stained ( Figures 2 View FIGURE 2 A–B, 3 A–B). Ventral shield of collar with dark stain, extending ventrally to second chaetiger. Thoracic chaetiger 2 is stained only in mid-ventrally, lateral margins are not stained or stained only slightly ( Figures 2 View FIGURE 2 A–B, 3 A–B). Other thoracic and abdominal segments are stained uniformly dorsally and ventrally.

Remarks: Chone cincta   is redescribed here and transferred to Paradialychone   . The species has diagnostic features of Paradialychone   : 1) thoracic uncini with the main fang surmounted by unequal-size teeth; 2) dorsoventral pre-pygidial depression; 3) anterior abdominal uncini with unequal-size teeth; and 4) posterior abdominal uncini as rasp-shaped plates. Paradialychone   contains twelve species ( Tovar-Hernández 2008); among which P. c i n c t a is unique in having thoracic paleate chaetae with short mucros and a horizontally stained, belt-like pattern of the collar. Most species in Paradialychone   have a medium-size or long mucro while only two have a minute or indiscernible mucro: P. eiffelturris   ( Tovar-Hernández 2007 a) and P. paramollis   ( Tovar-Hernández 2007 a). Paradialychone cincta   has a circular ventral collar shield, that is only slightly discernible; in P. eiffelturris   ( Tovar-Hernández 2007 a) it is Eiffel Tower-shaped and horseshoe-shaped in P. paramollis   . Among the species described in this study from Japan, P. c i n c t a is distinct in having paleate chaetae with short mucros (minute in P. katsuuraensis   n. sp.; see Tovar-Hernández et al., 2007, and long in P. edomae   n. sp.).

The population of P. c i n c t a from Tomioka (Ariake Sound) seems to have an indeterminate growth, as shown in Yun and Kikuchi (1991) and Yun and Nojima (1998). Future studies on members of Dialychone   , Paradialychone   and Euchone   need to take into account the number of chaetigers forming the pre-pygidial depression, since the number of segments, fixed or indeterminate, might be a useful character to distinguish species.

CBM

Natural History Museum and Institute

SAMA

South Australia Museum

MNHN

Museum National d'Histoire Naturelle

SMF

Forschungsinstitut und Natur-Museum Senckenberg

USNM

Smithsonian Institution, National Museum of Natural History

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Sabellida

Family

Sabellidae

Genus

Paradialychone

Loc

Paradialychone cincta ( Zachs, 1933 )

Nishi, Eijiroh, Tanaka, Katsuhiko, Tovar-Hernández, María Ana & Giangrande, Adriana 2009
2009
Loc

Chone cincta

Zachs 1933: 135
1933