Chone trilineata, 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: 554-555
treatment provided by
Chone trilineata n. sp.
( Figure 16 View Figure 16 )
Type material. California [ LACM-AHF (holotype, one paratype) Santa Monica Bay, Sta. 4, 5-1974]. Topotypes [ LACM-AHF], SMB, Rep. 5.5-6.0 # 5, 9 May 1979 (1) ; SMB, Rep. 8.3-6.0 # 6, 61 m, 11 May 1979 (1).
Non-type material. California [ CSD-MBL], San Diego, Sta. I, 1-1, 0.97 m, 23 July 1997 (1) . [ PC-RR], City of San Diego , A/0, Sta. B-13, 1 June 1999, 193 m (1). [ LACM-AHF], BLM, BFI, 22965 (1); 23153 (1); 80603 (1). [ LACM-AHF], ACE, LA-2, BD2-2/I, 8 May 1984 (1) . [ LACSD-MBL], Sta. 0205-8D, 60 m (1) . Baja California [EcoMar-UABC], Bahía de Todos Santos, South of Islas Coronado , Sta. E 2575-21, 32 ° 29.659N, 117 ° 20.559W, coll. V. Rodríguez-Villanueva, 2 September 1998 GoogleMaps , 65 m (1).
Description (based on holotype and paratype)
Colour, body shape, and size. Body cream coloured. Trunk cylindrical, posterior abdomen depressed dorso-ventrally. Body length 4.8 mm (5.5), width 0.5 mm. Tubes unknown.
Branchial lobes and branchial crown. Insertion of the branchial lobes exposed beyond collar ( Figure 16A, B, E View Figure 16 ). Branchial crown length 2.2 mm (3). Radioles: six pairs. Radioles with distal pinnules three times longer than more proximal pinnules. Radiolar tips long. The palmate membrane extends to three-quarters the length of branchial crown. Lateral flanges narrow. Dorsal lips three times longer than wide, erect, without mid-rib. Dorsal pinnular appendages: one short pair, united by a palmate membrane. Ventral lips rounded, small. Ventral radiolar appendages absent.
Peristomium . Anterior peristomial ring lobe (apr) exposed beyond collar, distally bilobed ( Figure 16B View Figure 16 ). Posterior peristomial ring collar: entire length of mid-dorsal collar margins forms a narrow gap ( Figure 16C View Figure 16 ); lateral and ventral margins entire ( Figure 16A, B, D, E View Figure 16 ); dorsal margin slightly higher than ventral ( Figure 16C, E View Figure 16 ). Ventral shield of collar horseshoe-shaped, as long as wide ( Figure 16A, B, D View Figure 16 ). Ratio of posterior peristomial ring collar length versus chaetiger 2 length, in lateral view: 1:1.
Thorax. Chaetiger 1: two groups of elongate, narrowly hooded chaetae. Chaetigers 2–8: notopodia—two irregular rows of elongate, narrowly hooded chaetae; one anterior row with bayonet chaetae; two posterior rows with symmetrical; paleate chaetae with medium-sized mucro ( Figure 16H–J View Figure 16 ); neuropodia—one row of acicular uncini per torus, main fang surmounted by four rows of teeth equal in size, occupying half the length of main fang ( Figure 16J View Figure 16 ). Pre- and post-chaetal lobes well developed. Glandular ridge on chaetiger 2 (gr2): ventrally with a median, vertical projection, dorsally with two vertical projections, all projections directed towards anterior margin of second segment ( Figure 16A–E View Figure 16 ).
Abdomen. Abdominal segments: 24 (26). Anterior segments: two transverse rows of elongate, narrowly hooded chaetae ( Figure 16L View Figure 16 ). 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 ( Figure 16F, G View Figure 16 ), occupying threequarters the length of main fang, main fang not extending beyond breast, breast rectangular. Pygidium with triangular posterior margin ( Figure 16A View Figure 16 ).
Gametes. Female with oocytes (oo) from second thoracic segment ( Figure 16L View Figure 16 ) to posterior abdomen (LACM-AHF, SMB).
Methyl green staining. The epidermis is completely glandular and stains uniformly in thorax and abdomen, dorsally and ventrally, except the anterior margin of collar. The anterior end of the first ventral glandular shield and the extensions of the glandular ridge on chaetiger 2 are not coloured ( Figure 16A–E View Figure 16 ).
The specific name is Latin, meaning three-lined; and refers to the peculiar shape of the glandular ridge on chaetiger 2.
Chone trilineata n. sp. is unique among Chone species by having the glandular ridge on chaetiger 2 with one ventral and two dorsal projections directed anteriorly and the ventral margin of collar lower than dorsal (Table II). Chone trilineata n. sp., C. quebecensis n. sp., C. bimaculata , and C. veleronis have the insertion of the branchial lobes exposed beyond collar, and modified posterior abdominal uncini (Group II). All these species can be distinguished by the glandular ridge on chaetiger 2: in C. trilineata n. sp. the glandular ridge has one ventral and two dorsal projections directed anteriorly; in C. quebecensis n. sp. the ridge is broad ventrally; in C. bimaculata it is homogeneously broad; and in C. veleronis it is sunglasses-shaped ventrally.
Arachnid Collection of Egypt
Royal British Columbia Museum - Herbarium
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