Kirkegaardia chilensis, Blake, James A., 2016

Blake, James A., 2016, Kirkegaardia (Polychaeta, Cirratulidae), new name for Monticellina Laubier, preoccupied in the Rhabdocoela, together with new records and descriptions of eight previously known and sixteen new species from the Atlantic, Pacific, and Southern Oceans, Zootaxa 4166 (1), pp. 1-93: 58-60

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Kirkegaardia chilensis

new species

Kirkegaardia chilensis   new species

Figure 29 View FIGURE 29

Tharyx   spp. Hartman 1967:118 (in part).

Material examined. Pacific Ocean, off Western South America , Southwestern Chile, off Valparaiso, USNS Eltanin Cruise 9, Sta. 750, 33.02°S, 71.88°W, 624 m, coll GoogleMaps   . 26 September 1963, Petersen grab, holotype and paratype ( USNM 1013897–8 View Materials ); Cruise 5, Sta. 208, off Concepcion , 35.65°S, 73.13°W 957 m, coll GoogleMaps   . 11 September 1962, Menzies Trawl, 7 paratypes (USNM 56079), 1 additional paratype (USNM 1013899).

Description. A small species with thin, narrow body; holotype incomplete, 11.7 mm long, 0.35 mm wide across thorax for 56 setigers. Color in alcohol: light tan, no pigment apparent.

Each specimen with very elongate, smooth peristomial region; thoracic region narrow, with 16–20 crowded segments; venter swollen between about setigers 8–14 ( Fig. 29 View FIGURE 29 A); long abdominal region with longer segments, sometimes weakly moniliform; posterior end remaining narrow, not expanded in mostly complete paratypes, pygidium missing from all specimens. Abdominal segments with venter flattened, with weak mid-ventral channel containing low ridge extending along midline. Parapodia of thoracic region elevated over dorsal surface producing distinct mid-dorsal channel; middle surface of this channel raised forming a weak and narrow ridge ( Fig. 29 View FIGURE 29 B).

Pre-setigerous region elongate, 1.9x as long as wide. Prostomium short, oval, broadly rounded on anterior margin ( Fig. 29 View FIGURE 29 A–B); eyes absent; nuchal organs not observed. Peristomium about 1.8x as long as wide, smooth, with two weakly developed lateral grooves, often not apparent ( Fig. 29 View FIGURE 29 A–B); mid-dorsal peristomial ridge or crest absent; short proboscis everted on some specimens. Dorsal tentacles arising from posterior part of peristomium ( Fig. 29 View FIGURE 29 A–B); first pair of branchiae also on peristomium, posterolateral to dorsal tentacles ( Fig. 29 View FIGURE 29 A–B); second pair of branchiae on setiger 1 ( Fig 29 View FIGURE 29 B); following branchiae at posterior margin of individual setigers, dorsal to notosetae; branchiae all short, most missing.

Parapodia well developed in thoracic region, dorsally forming lateral borders of dorsal groove ( Fig. 29 View FIGURE 29 B); parapodia reduced to setal tori posteriorly. Notosetae long capillaries throughout, up to 7–9 per fascicle in anterior setigers, decreasing to 5–6 posteriorly; denticulated notosetae absent; neurosetae, shorter, thicker than notosetae, numbering 8–10 per fascicle, with very fine denticles along shaft in middle abdominal setigers from setiger 30, visible only at 1000x ( Fig. 29 View FIGURE 29 C–D).

Methyl Green stain. Venter of expanded part of thorax stains weakly, otherwise no staining reaction.

Etymology. This species is named for its location on the Chilean continental slope.

Remarks. Kirkegaardia chilensis   n. sp. is part of the group of 12 species having the thoracic parapodia elevated over a mid-thoracic channel and is most similar morphologically to K. dorsobranchialis   , K. carinata   n. sp., and K. cryptica   in having an entirely smooth peristomium with no dorsal ridge. Of these, K. carinata   n. sp. and K. chilensis   n. sp. have a prominent mid-dorsal ridge within the thoracic dorsal channel that is absent in both K. dorsobranchialis   and K. cryptica   . K. chilensis   n. sp. differs from K. carinata   n. sp. in having only a weak MG staining pattern limited to the thoracic region instead of the intense and spectacular pattern on the peristomium, thoracic region, and abdominal parapodia of K. carinata   n. sp. In addition, the mid-ventral segments of the thoracic region of K. chilensis   n. sp. are expanded, whereas all of the thoracic segments of K. carinata   n. sp. are the same size.

Distribution. Off western Chile, slope depths of 624– 957 m.


Smithsonian Institution, National Museum of Natural History














Kirkegaardia chilensis

Blake, James A. 2016


Hartman 1967: 118