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

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 : 7-11

Paradialychone edomae new species

Japanese name: Umetate-Keyarimushi Figures 4–5

Chone sp. Aleutian Islands Tovar-Hernández, 2007b: 56 –58, Figure 15.

Material examined. Type material: HOLOTYPE — CBM –ZW 1011, Heneda, Tokyo Bay, St. 11a, N35.5530, E139.7980, shallow water, by grab-sampler, May 2006. PARATYPES —CBM-ZW 1012, Haneda, Tokyo Bay, St. 11a, N35.5530, E139.7980, shallow water, by grab-sampler, May 2006. CBM-ZW 1013, Haneda, Tokyo Bay, St. 11a, N35.5530, E139.7980, shallow water, by grab-sampler, May 2006. NHM-ANEA.2009.13, Haneda, Tokyo Bay, St.31, N35.52666855, E139.7906647, May 2006, by grab-sampler. NHM-ANEA.2009.14, Haneda, Tokyo Bay, St. 11a, May 2006, by grab-sampler. USNM 1123949, Haneda, Tokyo Bay, St.45c, N35.5364, E139.8070, May 2006, by grab-sampler. SAMA E 3723, Haneda, Tokyo Bay, St. 11a, N35.5530, E139.7980, shallow water, by grab-sampler, May 2006. SAMA E 3722, Haneda, Tokyo Bay, St.31L, N31, 35.52666855, E139.7906647, May 2006. SMF 18132(4 specimens), Haneda, Tokyo Bay, St. 21L, May 2006. KMNH-IvR- 500.417, KMNH IvR 500,423, 2 specimens, Haneda, Tokyo Bay, St. 31, N35.52666855, E139.7906647, Haneda, May 2006. ZIHU-3805, Haneda, Tokyo Bay, St. 31, N35.52666855, E139.7906647, Haneda, May 2006. OMNH-Iv5027, Haneda, Tokyo Bay, St. 31, N35.52666855, E139.7906647, Haneda, May 2006. ZMUC- POL-2059, Haneda, Tokyo Bay, St.45c, N35.5364, E139.8070, May 2006, by grab-sampler. MNHN TYPE 1494 - Haneda, Tokyo Bay, Stn. 45C, N35.5364, E139.8070, May 2006 (5 specimens). MBM119722, Haneda, Tokyo Bay, St. L2b, N35.31.31.2, E139.47.35.4, 3 m, May 2007. BPBM-R3392 (3 specimens), Haneda, Tokyo Bay, St. 11a, N35.5530, E139.7980, shallow water, by grab-sampler, May 2006. Paratypes. CMNH-ZW 1687, St. L2b, N35.31.31.2, E139.47.35.4, 3 m, May 2008. ZMB Vermes 11370, Haneda, Tokyo Bay, St. 11a, N35.5530, E139.7980, shallow water, by grab-sampler, May 2006. CMNH-ZW 1688, Haneda, Tokyo Bay, St. 11a, N35.5530, E139.7980, shallow water, by grab-sampler, May 2006.

Description. Body cream-colored. Body cylindrical, posterior abdomen compressed dorso-ventrally. Body length: 10 mm in holotype, 10–14 mm in paratypes, width: 1.0 mm in holotype, 1.0– 1.2 mm in paratypes. Tubes thin, membranous. Base of branchial crown shorter than collar. Insertion of branchial lobes exposed beyond collar dorsally ( Figure 5 A, C). Branchial crown length 2.5 mm in holotype, 2.0–4.0 mm in paratypes. Radioles 15 pairs in holotype, 15–18 pairs in paratypes. Palmate membrane extends on half to two thirds length of crown. Lateral flanges narrow along the outer edges of radioles. Radiolar tips filiform (1 mm versus 3 mm crown length) ( Figure 5 D). Radiolar skeleton with two rows of cells. Distal pinnules longer than more proximal pinnules. Dorsal lips medium-sized, elongate, two to three times longer than wide, without mid-rib ( Figure 5 E). A pair of dorsal pinnular appendages united by a thin web ( Figure 5 E). Ventral lips rounded, one pair of ventral pinnular appendages extending one quarter to three quarters of crown length ( Figure 5 E). Anterior peristomial ring lobe exposed beyond collar, bilobed ( Figure 5 B). Collar entire ( Figures 4 A, C, 5A–C), ventral margin higher than dorsal ( Figure 5 C); entire length of mid-dorsal collar margins form broad gap, faecal groove wide ( Figure 5 A). Dorsal pockets well developed ( Figures 4 A, 5A). Ventral shield of collar horseshoe shaped, two times wider than longer swollen, with semi-transparent area above shield ( Figures 4 B, 5B–C). Ratio of posterior peristomial ring collar length versus chaetiger 2 length, in lateral view: 2:1. Chaetiger 1 with two groups of elongate, narrowly hooded chaetae. In notopodia of chaetigers 2 to 8, two irregular rows of elongate, narrowly hooded chaetae ( Figure 5 G), one row with bayonet chaetae, two posterior rows of paleate chaetae with long mucros ( Figures 4 C–D, 5F). Acicular uncini with three rows of teeth in lateral view ( Figures 4 E–F, 5H); 4–5 rows of unequal-size teeth over main fang in frontal view ( Figure 4 F), dentition covering one half of main fang length. Glandular girdle on chaetiger 2 is located near anterior margin of second segment dorsally and ventrally, laterally near posterior margin ( Figures 4 A–B, 5A–C). Glandular girdle of equal width all around and ca. 1/4 the lateral length of the segment ( Figure 4 A–B). Posterior end with dorsoventral pre-pygidial depression. Abdominal segments 41 in holotype, 42–75 in paratypes. Anterior segments with two transverse rows of 6–7 elongate, narrowly hooded neurochaetae, upper row chaetae half as long as lower row; 10–12 uncini per torus with first tooth above main fang larger than subsequent 3–4 tooth rows ( Figures 4 G–H, 5I), main fang not extending beyond breast, breast rectangular ( Figure 5 I). Posterior segments with 1–2 elongate, narrowly hooded chaetae, 50% longer than in anterior segments; 5–8 uncini per torus, breast quadrangular to hooked, with 5–6 rows of equal size teeth, as raspshaped ( Figures 4 I, 5J). Ventral, longitudinal glandular band on posterior part of abdomen. Pygidium with triangular posterior margin.

Glandular pattern: Anterior one fourth of collar does not stained, posterior three fourth dark. Semitransparent rectangular area not stained ( Figure 4 A–B). Shield of collar deeply stained. Remainder of body stains uniformly dorsally and ventrally.

Remarks: The account of Tovar-Hernández (2007b) included a species described as Chone sp. from Aleutian Islands. Later, this species was included in her cladistic analysis ( Tovar-Hernández 2008) in which, it lay within Chone . However, our re-examination of materials (Los Angeles County Museum of Natural History), showed that those specimens agree with the diagnostic features for Paradialychone (see remarks section for P. c i n c t a) by having thoracic uncini with a large tooth offset from midline and dentition covering three-quarters of the main fang length (scored as having a teeth in midline and dentition covering one-quarter of the main fang length in Tovar-Hernández, 2007b); and posterior abdominal uncini modified (scored as not modified in Tovar-Hernández, 2007b). Specimens from Japan correspond in each feature to Chone sp. of Aleutian Islands.

Only three Paradialychone species have the anterior peristomial ring lobe bilobed and extended beyond the collar: P. edomae n. sp., P. gambiae (Tovar-Hernández et al. 2007) and P. bimaculata ( Banse and Nichols 1968) . Paradialychone gambiae is characterized by the presence of a glandular girdle on chaetiger 9; P. bimaculata has a pygidial cirrus, and Paradialychone edomae n. sp. has a longitudinal glandular band down the posterior abdomen and horse shoe-shaped ventral collar shield. Among Japanese species, P. edomae differs from P. c i n c t a and P. katsuuraensis n. sp., by having paleate chaetae with long mucros (short in P. cincta , medium-sized in P. katsuuraensis ) and an anterior peristomial ring lobe bilobed and extended beyond the collar. The well developed collar with pockets is also considered to be a diagnostic character.

Among species in the related genera ( Chone , Dialychone and Paradialychone ), only Paradialychone edomae and Dialychone quebecensis ( Tovar-Hernández 2007a) share the presence of a ventral, longitudinal glandular band on the posterior part of the abdomen.

Etymology: The specific epithet refers to the old name of the coastal area of Tokyo, Edomae , where the new species was found. The Japanese name is derived from umetate, meaning reclamation, in combination with, keyarimushi, meaning sabellid polychaetes, because the present distributional area of P. edomae will be reclaimed for the enlargement of Tokyo International Airport within three years.

Figures

FIGURE 4. Paradialychone edomae sp. nov. A, methyl green stained holotype, dorsal view. B, methyl green stained holotype, ventral view. C – I, SEM micrographs of chaetae and uncini from paratype CMNH – ZW 1688. C – D, thoracic paleate chaetae. E – F, thoracic uncini. G, anterior abdominal uncini. H – I, posterior abdominal uncini. Scale: 1 mm in A – B.

FIGURE 5. Paradialychone edomae sp. nov. A – C, dorsal, lateral and ventral views, respectively, of holotype thorax. D, radiolar tips, paratype CBM-ZW 1012. E, inner view of crown, paratype CBM-ZW 1012. F – J, chaetae and uncini, paratype CMNH-ZW 1688. F – G, thoracic narrowly hooded chaetae. H, thoracic uncinus. I, abdominal uncinus, chaetiger 9. J, abdominal uncinus from most posterior chaetiger. Abbreviations: aprl, anterior peristomial ring lobe; gg, glandular girdle; vl, ventral lip; vpa, ventral pinnular appendage. Scales 1 mm in A – E, 25 µm in F – J.