Chone paramollis, Tovar-Hernández, 2007

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 : 542-548

Chone paramollis n. sp.

( Figure 11 )

Material examined

Type material. California [ LACM-AHF 003251 , 1958 , Tomales Bay , holotype, 80 paratypes; ECOSUR 0073 , five paratypes]. Topotypes [ LACM-AHF], 003218 (5); 003238, # 2 8-58 (various dozens); 003240, # 6, coll. G. Jones, August 1958 (11) ; 003246, 4938-57 (4); 003247, 5028-57 (10); 003248, 5745 (1); 003250 (6).

Non-type material. California [ LACM-AHF], Marina del Rey, MMS Phase I, Help Collections , MDR 2A, 21 September 1978 (12) . MDR 4A, 21 September 1978 (3). [ LACM-AHF], Santa Monica Bay, Repl. Study, Sta. 83-60 # 1, 62 m, 11 May 1979 (1) ; Sta. 83-60 # 3, 62 m, 11 May 1979 (1). [LACM-AHF], Newport, 003241, Sta. 9, January 1954 (1) . [ CSD-MBL], Point Loma, Sta. A-12, 32 ° 40.479N, 117 ° 16.429W, 4 January 1981 , 47 m (1); Sta. I-8, 35 m, 13 February 2005 (2). [ LACSD-MBL], San Diego, Sta. Y 6D, 30 m (10). Sta. 0102-3D, 30 m (1). Sta. 0703-3D, 30 m (2). Sta. 0194-2D, 30 m (1). Sta. 0191-7D, 30 m (1). [ PC-RR], City of San Diego , ITP I-2, 32 m, 1 July 2002 , RCR DLZ 1089 (1); San Diego Bay , SB03, 10.4 m, 13 April 2004 (2) . [ LACM-AHF BLM 24242 BFI] (1). [ LACM-AHF BFI], BLM 6846-60 , 003219 (1). Western Mexico [ ECOSUR], Bahía La Paz , Calerita, coll. SISV, 12 June 1987 (2).

Additional material. Chone mollis ( Bush in Moore , 1904) [ YPM 2793 , holotype] .

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

Colour, body shape, and size. Body pink. Trunk depressed dorso-ventrally, posterior abdomen with a dorso-ventral depression ( Figure 11E ). Body length 20 mm (13–24), width 1 mm (0.9–1). Tubes unknown.

Branchial lobes and branchial crown. Insertion of branchial lobes not exposed beyond collar ( Figure 11A, B ). Branchial crown length 5 mm (4). Radioles: eight pairs (seven to eight). Radioles with median pinnules twice the length of proximal pinnules. Radiolar tips long ( Figure 11G ). The palmate membrane extends to three-quarters the length of branchial crown. Lateral flanges narrow. Dorsal lips (dl) triangular, elongate, erect, without mid-rib ( Figure 11F ). Dorsal pinnular appendages: two pairs. Ventral lips rounded, as long as wide, about one-quarter the length of dorsal lips. Ventral radiolar appendages: one pair, occupying one-half the length of branchial crown.

Peristomium . Anterior peristomial ring lobe triangular at their base, then digitiform, not exposed beyond collar. Posterior peristomial ring collar: antero-dorsal margin forming well-developed dorsal pockets, entire length of mid-dorsal collar margins forms a narrow gap ( Figure 11C ); lateral and ventral margins entire ( Figure 11A, B, D ); ventral margin slightly higher than dorsal ( Figure 11B ). Ventral shield of collar horseshoe-shaped, swollen, as wide as long ( Figure 11D ). Ratio of posterior peristomial ring collar length versus chaetiger 2 length, in lateral view: 2:1.

Thorax. Chaetiger 1: elongate narrowly hooded chaetae. Chaetigers 2–8: notopodia—two irregular rows of elongate, narrowly hooded chaetae; one anterior row with bayonet chaetae ( Figure 11O ); two posterior rows with five symmetrical, paleate chaetae with minute or indiscernible mucro ( Figure 11H, I ); neuropodia—one row of acicular uncini per torus, main fang surmounted by four rows of teeth equal in size, second tooth enlarged, located offset midline, dentition occupying three-quarters the length of main fang ( Figure 11J ). Pre- and post-chaetal lobes well developed. Glandular ridge on chaetiger 2: narrow.

Abdomen. Abdominal segments: 46 (37–43). Anterior segments: two transverse rows of elongate, narrowly hooded chaetae, chaetae from upper row half as long as chaetae in lower row; uncini with the main fang surmounted by three regular rows of teeth in frontal view, second tooth enlarged, dentition occupying half the length of main fang, main fang not extending beyond breast, breast rectangular ( Figure 11K, L ). Posterior segments: one or two very elongate, narrowly hooded chaetae, modified uncini with the main fang surmounted by six to seven regular vertical rows of teeth equal in size, occupying threequarters the length of main fang, main fang not extending beyond breast, breast rectangular ( Figure 11M, N ). Pygidium with triangular posterior margin ( Figure 11E ).

Gametes. Holotype female with oocytes in thorax and mid-abdominal region, different sizes.

Methyl green staining. The epidermis is completely glandular and stains uniformly in thorax and abdomen, dorsally and ventrally, except the anterior margin of collar ( Figure 11A–C ). The anterior end of the first ventral glandular shield is not coloured, lateral sides of ventral shield of collar dark ( Figure 11A–C ). Posterior end granular ( Figure 11E ). After 24 h specimens lost colour; only two glandular rings per segment are visible.

Etymology

Specific name refers to the similarity between this species and Chone mollis .

Remarks

The collar segment of Chone paramollis n. sp. resembles Chone mollis ; however, C. paramollis n. sp. has modified posterior abdominal uncini (Group II), which are not modified in C. mollis (Group I); the ventral shield of collar is as long as wide in C. paramollis n. sp. (two times wider than long in C. mollis ); the anterior peristomial ring lobe not exposed beyond collar (exposed in C. mollis ); the posterior peristomial ring collar length is two times longer than first chaetiger length (1.5 in C. mollis ). Chone paramollis n. sp. and C. eiffelturris n. sp. are unique among species of Chone from Group II in having paleate chaetae with a minute or indiscernible mucro: C. paramollis n. sp. has long radiolar tips (extremely long in C. eiffelturris n. sp.); the palmate membrane extends three-quarters of the branchial crown length (more than three-quarters, almost reaching radiolar tips, in C. eiffelturris n. sp.); ventral shield of collar horseshoe-shaped (‘‘A’’-shaped in C. eiffelturris n. sp.) and lacking glandular ridges in thorax and anterior abdominal segments (present in C. eiffelturris n. sp.).

Chone picta ( Verrill, 1885) new combination

( Figure 12 )

Sabella picta Verrill 1885, p 440 .

Material examined

Topotype material. Massachusetts [ YPM 30000], Martha’s Vineyard, off Gay Head , R / V A. E. Verrill, Naturalist Dredge, 126 ft, SEP 1789 , coll. V. A. Zullo, T. J. M. Schopf, J. M. Reinhart, and E. P. McReynolds, 6 June 1969 (1) . [ YPM 30002], Off Gay Head , 2400 m from CC Buoy, 70 ° 519N, 41 ° 229W, 90–110 ft, SEP 1155, coll. J. L. Simon and P. E. Schwamb, 22 June 1966 (1).

Non-type material. Massachusetts [ YPM 34894] , 6400 m S of Fishing Ledge , 41 ° 52.79N, 70 ° 18.59W, R / V A. E. Verrill, Epibenthic Dredge, 105 ft, SEP 1620 Ep, coll. Biotic Census, 19 December 1967 (1). [ YPM 30001], Cape Cod Bay , 11,200 m ENE of Manomet Point , 41 ° 56.69N, 70 ° 29.19W, R / V A. E. Verrill, Smith-McIntyre Grab, 140 ft, SEP 1224 E1, coll. Biotic Census, 3 March 1968 (2). [ YPM 34891], 2400 m off Race Point, Provincetown , 42 ° 03.59N, 70 ° 16.009W, R / V A. E. Verrill, Smith-McIntyre Grab, 188 ft, SEP 0518 E2, coll. Biotic Census, 14 May 1968 (1). [ YPM 34895], Off Fishing Ledge , 41 ° 50.59N, 70 ° 18.59W, R / V A. E. Verrill, scuba, 105 ft, SEP 1220, dive, coll. D. Grant, R . Wilce, C. McKay, and J. Sears, 26 August 1968 (1). [ YPM 34896], Off Fishing Ledge , 41 ° 50.59N, 70 ° 18.59W, R / V A. E. Verrill, scuba, 105 ft, SEP 1220, dive, coll. D. Grant, R . Wilce, C. McKay, and J. Sears, 26 August 1968 (1). [ YPM 34906], Fishing Ledge , 41 ° 50.59N, 70 ° 18.59W, R / V A. E. Verrill, Smith-McIntyre Grab, 94 ft, SEP. 1220 E1, coll. Biotic Census, 26 August 1968 (1). [ YPM 34902] , 6400 m N of Barnstable Harbor , 41 ° 47.59N, 70 ° 18.679W, R / V A. E. Verrill, Smith-McIntyre Grab, 66 ft, SEP 2118 ES, coll. Biotic Census, 14 October 1968 (1). [ YPM 34905] , 4800 m NE of McIntyre, 120 ft, SEP 1028 E4 (1). [ YPM 34899], 4800 m NE of east end of Cape Cod Canal , 41 ° 49.29N, 70 ° 27.79W, R / V A. E. Verrill, Naturalist Dredge, 83–90 ft towed 2 min, 500 ft, SEP 1820 N, coll. Biotic Census, 19 November 1968 (1). [ YPM 34900], 4800 m NE off east end of Cape Cod Canal , 41 ° 49.29N, 70 ° 27.79W, R / V A. E. Verrill, Naturalist Dredge, 86 ft, SEP 1926 N, coll. Biotic Census, 19 November 1968 (1). [ YPM 34893] , 11,200 m NE of Manomet Point , 41 ° 58.59N, 70 ° 24.09W, R / V A. E. Verrill, Smith-McIntyre Grab, 154 ft, SEP 1024 E1, coll. Biotic Census, 19 December 1968 (3). [ YPM 34901] , 11,200 m NE of Manomet Point , 41 ° 58.59N, 70 ° 24.09W, R / V A. E. Verrill, Naturalist Dredge, 152 ft, SEP 1024 N, coll. Biotic Census, 19 December 1968 (1). [ YPM 34909], Off Barnstable Harbor , 41 ° 46.59N, 70 ° 18.69W, R / V A. E. Verrill, Smith-McIntyre Grab, 68 ft, SEP 2220 E5, coll. Biotic Census, 7 January 1969 (1).

Redescription

Colour, body shape, and size. Body cream coloured. Verrill (1885): ‘‘color of the body greenish, specked with bright red, most so posterior and anteriorly, on the collar the red predominates. Branchiae transparent greenish white, with transverse spots of flake-white and bright red; bases light red’’. Trunk cylindrical. Body length 20.7–40.7 mm, width 2– 2.5 mm.

Branchial lobes and branchial crown. Insertion of the branchial lobes not exposed beyond collar dorsally ( Figure 12A ). Branchial crown length 6–11 mm. Radioles: 12–15 pairs. Radioles with median pinnules two times longer than more proximal pinnules. Radiolar tips short. The palmate membrane extends up half the length of branchial crown. Lateral flanges broad. Dorsal lips (dl) two times longer than wide, rounded, erect, without mid-rib ( Figure 12E ). Dorsal pinnular appendages: one to three short pairs. Ventral lips rounded, as long as wide, about one-quarter the length of dorsal lips. Ventral radiolar appendages: one to three pairs, the inner one about three-quarters the length of branchial crown, the remainder about one-quarter the length of branchial crown.

Peristomium . Anterior peristomial ring lobe not exposed beyond collar, distally entire, triangular ( Figure 12A ). Posterior peristomial ring collar: antero-dorsal ( Figure 12A ), lateral ( Figure 12C ) and ventral margins entire ( Figure 12B ); ventral margin slightly higher than dorsal ( Figure 12C ); entire length of mid-dorsal collar margins forms a broad gap and a deep faecal groove ( Figure 12A ); dorsal pockets well developed. Ventral shield of collar swollen, horseshoe-shaped, as long as wide ( Figure 12B ). Ratio of posterior peristomial ring collar length versus chaetiger 2 length, in lateral view: 3:1.

Thorax. Chaetiger 1: two groups of four to six elongate, narrowly hooded chaetae. Chaetigers 2–8: notopodia—two rows of four to five elongate, narrowly hooded chaetae ( Figure 12F ); inferior group with one row with four to five bayonet chaetae ( Figure 12G ), two posterior rows with five symmetrical, paleate chaetae without mucro ( Figure 12I, J ); neuropodia—one row of 8–13 acicular uncini per torus, 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 12H ). Pre- and post-chaetal lobes well developed. Glandular ridge on chaetiger 2: narrow.

Abdomen. Abdominal segments: 54–56. Anterior segments: two transverse rows of elongate, narrowly hooded chaetae ( Figure 12K ), uncini with the main fang surmounted by three rows of teeth equal in size, occupying half the length of main fang, main fang not extending beyond breast, breast rectangular ( Figure 12L ). Posterior segments: very elongate, narrowly hooded chaetae, uncini similar to those in anterior abdomen ( Figure 12M ). Pygidium with posterior margin rounded ( Figure 12D ).

Gametes. Females with oocytes in thorax and middle abdominal region.

Methyl green staining. Basal half of collar dark, distal half not coloured; ventral shield of collar dark on basal half, distal half not coloured. Body coloured uniformly.

Remarks

Bush in Moore (1904, p 216) mentioned that Sabella picta Verrill (1885) is a Metachone , but provided no details. Hartman (1942a, p 136) synonymized Sabella picta Verrill, 1885 with C. infundibuliformis ; however, C. picta is distinguished by a broad faecal groove (narrow in C. infundibuliformis ), paleate chaetae without mucro (short mucro in C. infundibuliformis ), dorsal pockets well developed (poorly developed in C. infundibuliformis ), and posterior peristomial ring collar three times as long as chaetiger 2 (two times in C. infundibuliformis ) (Table III).

Figures

Figure 11. Chone paramollis n. sp. (A) Body, lateral view; (B) anterior end, dorsal view; (C) same, ventral view; (D) same, lateral view; (E) posterior end; (F) left branchial lobe; (G) radiolar tip; (H, I) paleate chaetae; (J) thoracic uncini; (K, L) anterior abdominal uncini; (M, N) posterior abdominal uncini; (O) bayonet chaeta. (A–D) Methyl green staining. (A–C, E) [LACM-AHF 003251, holotype]; (D, F, G–O) [LACM-AHF, paratype].

Figure 12. Chone picta. (A) Anterior end, dorsal view; (B) same, ventral view; (C) same, lateral view; (D) posterior end, lateral view; (E) branchial lobe; (F) thoracic, elongate, narrowly hooded chaeta; (G) bayonet chaeta; (H) thoracic uncinus; (I, J) paleate chaetae; (K) abdominal, elongate chaeta; (L) anterior abdominal uncinus; (M) posterior abdominal uncinus. [YPM 30002, topotype].