Chone murmanica Lukasch, 1910

Tovar-Hernández, María Ana, 2007, On some species of Chone Krøyer, 1856 (Polychaeta: Sabellidae) from world-wide localities, Zootaxa 1518, pp. 31-68 : 49-50

Chone murmanica Lukasch, 1910

Figure 10

Chone murmanica Lukasch, 1910: 21 –26.

Material examined. Non-type material. Arctic Ocean [ LACM – AHF], Beaufort Sea, Northwest of Cape Halkett, Alaska, Coll. Andrew Carey: 948–04 (3); 835–04 (141); 836–03 (145). [ ZIRAS 38178] Franz-Joseph Land, September 29, 1970, 28–30 m, pebble and sand (2).

Diagnosis. Body elongated, cylindrical. Body length 18 mm. Branchial crown length 4 mm. Branchial lobes short. Radiolar tips extra long. Narrow flanges. Anterior peristomial ring lobe exposed beyond collar (aprl), bilobed ( Figs 10 B–C). Ventral collar margin higher than dorsal one, bilobed ( Figs 10 B–C). Entire length of mid-dorsal collar margins forms a very broad gap ( Fig. 10 A). Dorsal pockets well developed ( Fig. 10 A). Peristomial eyes present (pe) ( Figs 10 B–C). Paleate chaetae with long mucro ( Figs 10 D–E); thoracic uncini with four rows of teeth ( Fig. 10 F); thoracic narrowly hooded chaetae ( Figs 10 K–L). Glandular ridge on chaetiger 2 narrow. Ventral thoracic shields well developed. Abdominal segments: 26. Abdominal chaetae narrowly hooded ( Figs 10 M–N); posterior abdominal uncini modified with six rows of teeth ( Figs. 10 H–J). Pygidium with triangular posterior margin.

Methyl green staining. Dorsally there is no colour, only lateral spots in the collar, laterally, the following segments have glandular spots ( Fig. 10 A). Ventrally: collar segment stained uniformly, except the anterior margin, and the area where the otoliths occurs ( Figs 10 B–C).

Gametes. Spermatozoa with barrel-shaped nucleus, triangular, short acrosome, two small, rounded mitochondria ( Fig. 10 G).

Remarks. Cochrane (2000) stated that the illustration of the anterior end of C. murmanica , depicted in Lukasch (1910) indeed closely resembles the drawing of C. paucibranchiata by Kr ø yer. Both taxa have three pairs of radioles and a characteristically pronounced dorsal gap in the collar. Chone paucibranchiata has been regarded as a junior synonym of Chone infundibuliformis Kr ø yer, 1856 after Malmgren (1866), but Banse (1972) stated that C. paucibranchiata has well developed ventral glandular shields (absent in C. infundibuliformis ); and that its palmate membrane extends at least one-third of the branchial crown length (two thirds in C. infundibuliformis ). If C. paucibranchiata is regarded as a valid species, it would have priority over C. murmanica , but examination of topotype material is necessary in order to confirm the synonym. Among species of Chone included in this revision, C. murmanica is unique by having a ventral shield of collar in trapezoidshaped ( Table 2 ).

Figures

FIGURE 10. Chone murmanica. (A) Anterior end, dorsal view; (B – C) same, ventral views; (D – E) paleate chaetae; (F) thoracic uncinus; (G) spermatozoon; (H – J) posterior abdominal uncini; (K – L) thoracic chaetae; (M) anterior abdominal chaeta; (N) posterior abdominal chaeta. (A – C) Methyl green staining. (A) [ZIRAS 38178]; (B – N) [LACM – AHF Carey OSU].