Chaetozone biannulata, Blake, 2018

Blake, James A., 2018, Bitentaculate Cirratulidae (Annelida, Polychaeta) collected chiefly during cruises of the R / V Anton Bruun, USNS Eltanin, USCG Glacier, R / V Hero, RVIB Nathaniel B. Palmer, and R / V Polarstern from the Southern Ocean, Antarctica, and off Western South America, Zootaxa 4537 (1), pp. 1-130 : 75-77

publication ID

https://doi.org/ 10.11646/zootaxa.4537.1.1

publication LSID

lsid:zoobank.org:pub:169CBE5C-3A6E-438B-8A81-0491CBFBAC85

DOI

https://doi.org/10.5281/zenodo.3798558

persistent identifier

https://treatment.plazi.org/id/03A2CB16-FFBF-A206-FF36-FA72FB2DFA90

treatment provided by

Plazi

scientific name

Chaetozone biannulata
status

sp. nov.

Chaetozone biannulata View in CoL new species

Figures 40–41 View FIGURE 40 View FIGURE 41

Tharyx marioni: Hartman, 1967: 118 View in CoL (in part).

Chaetozone setosa: Hartman, 1978: 166 View in CoL . Not Malmgren, 1867.

Chaetozone View in CoL sp.: Hartman, 1978: 166 (in part).

Chaetozone View in CoL sp. 1: Blake & Narayanaswamy 2004: 1806, 1813.

Chaetozone View in CoL sp. 2: Blake & Narayanaswamy 2004: 1813.

Chaetozone View in CoL sp. 3: Hilbig 2001: 540 (in part); Hilbig et al. 2006: 715, 717, 719, 724 (in part); Montiel et al. 2005: 197, 2016: Appendix 2 (in part).

Material Examined. Drake Passage, North of South Shetland Islands, R / V Polarstern, ANDEEP I (ANT-XIX/ 3), Sta. PS 61/114-6, 18 Feb 2002, 61°43.55ʹS, 60°43.87ʹW, box corer, 2905 m, holotype ( SMF 24915) and 14 paratypes ( SMF 24916); Sta. PS 61/114-5, 18 Feb 2002, 61°43.55ʹS, 60°43.87ʹW, MUC, 2917 m, 5 paratypes ( SMF 24917); Sta. PS 61/114-8, 18 Feb 2002, 61°43.46ʹS, 60°43.29ʹW, box corer, 2881 m, 3 paratypes ( SMF 24918); Sta. PS 61/40-4, 26 Jan 2002, 58°55.27ʹS, 61°0.02ʹW, box corer, 1838 m, 1 paratype ( SMF 24919); Sta GoogleMaps .

PS61/43-2, 29 Jan 2002, 60°26.95ʹS, 56°4.96ʹW, box corer, 3957 m, (16, SMF 24920); Drake Passage, USNS Eltanin, Cr. 4, Sta. 126 , 29 Jul 1962, 57°12ʹS, 62°48ʹW, 3733–3806 m (5, USNM 56004 About USNM ); off King George Island , R / V GoogleMaps Polarstern, EASIZ II (ANT-XV/3) , coll. B. Hilbig, Sta. 48-334, 19 Mar 1998, 61°26.7ʹS, 58° 06.6ʹW, MG GoogleMaps , 1028 m (1, MCZ 149850 About MCZ ); Sta. 48-341 , 19 Mar 1998, 61°34.5ʹS, 58°07.0ʹW, MG GoogleMaps , 429 m (8, MCZ 149851 About MCZ ).— Scotia Sea , R / V Polarstern, ANDEEP I (ANT-XIX/3), Sta. PS61/46-3, 01 Jan 2002, 60°37.92ʹS, 53°57.17ʹW, box corer, 2888 m, 6 paratypes ( MCZ 24921); Sta. PS61/46-5 GoogleMaps , 01 Jan 2002, 60°38.13ʹS, 53°57.68ʹW, box corer, 2894 m (1 juvenile, SMF 24922).— Scotia Sea , Powell Basin, R / V GoogleMaps Polarstern, ANDEEP III (ANT- XXII/3), Sta. PS67/121-12, 15 Mar 2005, 63°36.19ʹS, 50°37.15ʹW, box corer, 2657 m, (1, SMF 24923); Sta. PS67/ 142-7 GoogleMaps , 18 Mar 2005, 62°11.61ʹS, 49°29.45ʹW, box corer, 3406 m (3, SMF 24924); Sta. PS67/151-6 GoogleMaps , 21 Mar 2005, 61°45.55ʹS, 47°7.56ʹW, box corer, 1180 m, 1 paratype ( SMF 24925); 1 paratype on SEM GoogleMaps Stub ( MCZ 149852 About MCZ ); Sta. PS 67/153-5 , 29 May 2005, 63°19.41ʹS, 64°36.82ʹW, MUC, 2079 m (1, SMF 24926).— Weddell Sea , off East Antarctic Peninsula, R / V GoogleMaps Polarstern, ANDEEP II (ANT-XIX/4) , Sta. PS61/131-8, 06 Mar 2002, 65°18.65ʹS, 51°30.91ʹW, box corer, 3068 m (1, SMF 24927); Sta. PS61/131-9 GoogleMaps , 06 Mar 2002, 65°18.55ʹS, 51°31.95ʹW, MUC, 3064 m, (1, SMF 24928); USCG GoogleMaps Glacier Sta. 68-5, 09 Feb 1968, 76°00ʹS, 55°00ʹW, VV grab, 400 m, (2 complete, USNM 46784 About USNM ); Sta. 68-40 GoogleMaps , 03 Mar 1968, 71°47.6ʹS, 40°41.3ʹW, 2949m (1, USNM 46785 About USNM ); Sta. 69-21 GoogleMaps , 13 Mar 1969, 73°52ʹS, 31°, 18ʹW, 2288 m, (2, USNM 46798 About USNM ); Sta. 69-4 , 26 Feb 1969, 77°05.5ʹS, 35°04ʹW, 743 m (1, USNM 46790 About USNM ).— Central Weddell Sea , R / V GoogleMaps Polarstern, ANDEEP II (ANT-XIX/4) , Sta. PS61/138-7 17 Mar 2002, 62°58.01ʹS, 27°53.87ʹW, MUC, 4541 m (1, SMF 24931).— Weddell Sea , off South Sandwich Islands, R / V GoogleMaps Polarstern, ANDEEP II (ANT-XIX/4) , Sta. PS61/141-7, 22 Mar 2002, 58°24.91ʹS, 25°1.24ʹW, box corer, 2217 m (2, SMF 24929).— South Sandwich Trench , R / V GoogleMaps Polarstern, ANDEEP II (ANT-XIX/4) , PS61/142-5, 24 Mar 2002, 58°50.83ʹS, 23°58.61ʹW, MUC, 6337 m (2, SMF 24930).— Weddell Sea , off Coats Land, USCG GoogleMaps Glacier, Sta. 69-8, 2 Mar 1969, 77.603°S, 42.500°W, 585 m, (6 USNM 46793 About USNM ); Sta. 69-19 GoogleMaps , 11 Mar 1969, 74.105°S, 32.605°W, 1622 m (1); Sta. 69-20 GoogleMaps , 12 Mar 1969, 73.823°S, 31.682°W, 2288 m (1, USNM 46797 About USNM ).— South Shetland Islands , off King George Island, R / V GoogleMaps Polarstern, EASIZ II (ANT-XV/3) , coll. B. Hilbig, Sta. 48-326, 17 Mar 1998, 62°20.1ʹS, 58°38.8ʹW, MG GoogleMaps , 606 m (10, SMF 24932).— West Antarctic Peninsula , Bransfield Strait, USNS Eltanin Cr. 6, Sta. 416 , 02 Jan 1963, 63.67°S, 56.22°W, trawl, 494–507 m (1, USNM 1490765 About USNM ).— Ross Sea , E. McMurdo Sound, SW of Tent Island, Deep-Freeze II, USCG GoogleMaps Glacier, 77°43.1ʹS, 166°21.5ʹE, OPG Grab, 421 m, coll. W.L. Tressler (1, USNM 1490766 About USNM ).— South Pacific Ocean , East of New Zealand, 180 km east of Antipodes Islands, USNS GoogleMaps Eltanin Cr. 32, Sta. 2143, 26 Feb. 1968, 49.85°S, 178.583°E, Blake trawl, 2100 m (3, USNM 1490767 About USNM ) GoogleMaps .

Description. A moderate-sized species, holotype complete, 9.3 mm long, 0.65 mm wide across mid-body, 55 setigerous segments. Complete paratypes 9.3 to 11.8 mm long for 58–60 setigerous segments. Body with anterior segments short, about four times wider than long ( Fig. 40A View FIGURE 40 ), becoming widest in middle body at five times wider than long, then narrowing posteriorly to moniliform segments about 1.5 times as wide as long. Wide mid-body with enlarged stomach area apparent through body wall, sometimes enlarged and apparent externally, but not distending body to any extent. Dorsal grooves and ridges absent; venter with low mid-ventral ridge present from anterior to posterior segments. Posterior segments tapered over last 15 segments, with weak groove between elevated parapodia of cinctured segments bearing spines producing prominent armature. Color in alcohol light tan, with brown pigmentation dorsolateral in segmental grooves of some specimens.

Entire pre-setiger region elongate, triangular with three parts: prostomium, peristomium, and achaetous segment merging seamlessly with setiger 1. Prostomium elongate, triangular in dorsal view, 1.5x longer than wide, tapering to narrow tip ( Figs. 40A View FIGURE 40 , 41 View FIGURE 41 A–C); eyespots absent; nuchal organs prominent elevated lobes at posterior border with peristomium ( Figs. 40A View FIGURE 40 , 41 View FIGURE 41 A–C), each with circular opening bearing cilia ( Fig. 41A View FIGURE 41 inset), not pigmented. Peristomium indistinctly separated from prostomium and separately from achaetous segment by prominent transverse groove ( Figs. 40A View FIGURE 40 , 41 View FIGURE 41 A–C); peristomium with low dorsal crest and ventrally surrounding mouth; achaetous segment separated from peristomium by distinct dorsal groove, not continuing ventrally ( Figs. 40A View FIGURE 40 , 41 View FIGURE 41 A–C); achaetous segment extending posteriorly, merging with setiger 1 with only evidence of separation a weak lateral groove seen in SEM ( Fig. 41A View FIGURE 41 ); achaetous segment bearing dorsal tentacles followed by first pair of branchiae ( Figs. 40A View FIGURE 40 , 41 View FIGURE 41 A–C). Second pair of branchiae dorsal to notosetae on setiger 1; branchiae continuing on subsequent setigers throughout body.

Anterior parapodia reduced to low elevations from which setae emerge; individual segments denoted dorsally by transverse grooves ( Figs. 40A View FIGURE 40 , 41C View FIGURE 41 ). Middle parapodia reduced to individual setal tori. Posterior setigers becoming moniliform, then transitioning to cinctured segments with elevated membranes from which spines and capillaries emerge ( Figs. 40B View FIGURE 40 , 41E View FIGURE 41 ). Anterior setae all simple capillaries; sexually mature specimens with long natatory notosetae; 10–12 notosetae and 8–10 neurosetae in thoracic setigers; reduced to 6–8 noto- and neurosetae per fascicle in far abdominal segments; notosetae longer than neurosetae; fascicles of noto- and neurosetae arising close to one another. Notoacicular spines from setigers 34–35; neuroacicular spines from setigers 37–38. In cinctured segments, up to 10–11 spines in notopodia and 10–13 spines in neuropodia, or full cinctures with 20–24 spines on a side. In cinctures, thin capillaries typically alternating with notoacicular spines in lower part of fascicle and with neuroacicular spines in upper part of fascicle ( Fig. 41E View FIGURE 41 ). Spines curved, tapering to pointed tip ( Figs. 40C View FIGURE 40 , 41 View FIGURE 41 D–E).

Last few cinctured segments narrowing to pygidium bearing ventral, disc-like lobe ( Fig. 40B View FIGURE 40 ).

Methyl Green stain. Body stains more or less uniformly throughout; with a band of stain around the subapical part of the prostomium, tip of prostomium not staining at all; some stain concentrated in intersegmental grooves of mid-body segments.

Etymology: The species name biannulata is from the Latin, bis for two and annulatus for ringed, in reference to the two distinctly separate pre-setal rings consisting of the peristomium and an achaetous segment.

Remarks. Chaetozone biannulata n. sp. and C. australosetosa n. sp. form a species pair, with the first more common in deep-water slope depths and the second more common in shelf depths. Both species are unique among in the manner in which the peristomium is divided into two parts, the second of which is interpreted as an achaetous segment that merges seamlessly with the anterior border of setiger 1. The main differences between the two species are that C. biannulata n. sp. has a long, narrow triangular-shaped prostomium/peristomium whereas in C. australosetosa n. sp. this is short and conical. These differences result in the pre-setigerous region of C. australosetosa n. sp. being shorter and somewhat bulbous compared to the elongate triangular shape of C. biannulata n. sp.

Similarities and differences between C. australosetosa n. sp. and C. biannulata n. sp. with C. reticulata n. sp., another Antarctic species, and C. hystricosa from North America are discussed with C. australosetosa n. sp. (see above).

Habitat & biology. The majority of samples for which surficial sediment data was developed during ANDEEP I and II was predominately silt-clay with lesser amounts of sand or pebbles. The color of the mud was generally dark greenish-grey or brown ( Howe et al. 2004, 2007). There was considerable evidence of bioturbation in the sediment profile images ( Diaz 2004). The Powell Basin station sampled during ANDEEP III had surficial sediment that was fine-to-medium silt, poorly sorted with sand (3%), silt (66%), and clay (31%) ( Howe et al. 2007).

Eggs measuring 60–100 µm observed in several ovigerous females from the Weddell Sea.

Distribution: Drake Passage and Scotia Sea, 421–3957 m; Weddell Sea to South Sandwich Trench, 743–6337 m; off South Shetland Islands, 400–606 m; South Pacific Ocean, E of New Zealand, 2100 m.

R

Departamento de Geologia, Universidad de Chile

V

Royal British Columbia Museum - Herbarium

SMF

Forschungsinstitut und Natur-Museum Senckenberg

MG

Museum of Zoology

MCZ

Museum of Comparative Zoology

USCG

Universidad de San Carlos de Guatemala

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Terebellida

Family

Cirratulidae

Genus

Chaetozone

Loc

Chaetozone biannulata

Blake, James A. 2018
2018
Loc

Chaetozone

Blake, J. A. & Narayanaswamy, B. E. 2004: 1806
2004
Loc

Chaetozone

Blake, J. A. & Narayanaswamy, B. E. 2004: 1813
2004
Loc

Chaetozone

Hilbig, B. & Gerdes, D. & Montiel, A. 2006: 715
Montiel, A & Gerdes, D. & Hilbig, B. 2005: 197
Hilbig, B. 2001: 540
2001
Loc

Chaetozone setosa: Hartman, 1978: 166

Hartman, O. 1978: 166
1978
Loc

Chaetozone

Hartman, O. 1978: 166
1978
Loc

Tharyx marioni: Hartman, 1967: 118

Hartman, O. 1967: 118
1967
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