Chaetozone profunda, Blake, 2022

Blake, James A., 2022, New species and records of Caulleriella, Chaetocirratulus and Chaetozone (Annelida, Cirratulidae) from continental shelf and slope depths of the Western North Atlantic Ocean, Zootaxa 5113 (1), pp. 1-89 : 76-80

Chaetozone profunda new species

Figures 39–40

urn:lsid:zoobank.org:act:E8883B45-41EC-4A53-A09B-00760D02C47C

Chaetozone sp. 9 : Blake et al. 1987: C-2; Hilbig 1994: 940.

Chaetozone sp. 10 : Maciolek et al. 1987a: D-2; 1987b: D-2 (in part).

Chaetozone setosa: Maciolek et al. 1987a : D-2; 1987b: D-2 (in part). Not Malmgren, 1867.

Material examined. (198 specimens) Off New England, U.S. North Atlantic ACSAR Program, coll. G.W. Hampson, Chief Scientist. Sta. 8: Cruise NA-1, Rep. 1, 10 Nov 1984, 40°10.37′N, 67°37.43′W, 2175 m, holotype ( USNM 1661492 ) and 3 paratypes ( USNM 1661493 ) ; Rep. 3, 10 Nov 1984, 40°10.32′N, 67°37.38′W, 2180 m, 2 paratypes ( USNM 1661494 ) ; Cruise NA-4, Rep. 1, 25 Nov 1985, 40°10.21′N, 67°37.24′W, 2184 m, 1 paratype ( USNM 1661495 ) ; Cruise NA-5, Rep. 3, 25 Nov 1985, 40°10.25′N, 67°37.41′W, 2182 m (2, USNM 1661496 ) . Sta. 2: Cruise NA-6, Rep. 1, 24 Jul 1986, 40°57.27′N, 66°13.78′W, 2095 m, 2 paratypes ( USNM 1661497 . Sta. 3: NA-1, Rep. 1, 09 Nov 1984, 41°01.39′N, 66°20.16′W, 1350 m (1, USNM 1661498 ) ; Rep. 3, 09 Nov 1984, 41°01.41′N, 66°20.22′W, 1338 m (1, USNM 1661499 ) . Sta. 5: Cruise NA-1, Rep. 3, 05 Nov 1984, 40°05.29′N, 67°29.96′W, 2045 m, 3 paratypes ( USNM 1661500 ) ; Cruise NA-3, Rep. 2, 04 Jul 1985, 40°05.08′N, 67°29.85′W, 2060 m, 2 paratypes ( USNM 1661501 ) . Sta. 9: Cruise NA-5, Rep. 1, 03 May 1986, 39°50.54′N, 70°01.79′W, 1214 m (1, USNM 1661502 ) ; Sta. 15: Cruise NA-1, Rep. 2, 09 Dec 1984, 39°54.26′N, 70°54.26′W, 2154 m, 1 paratype ( USNM 1661503 ) .— Off Delaware and New Jersey, U.S. Mid-Atlantic ACSAR Program , coll. R. Petrecca, Chief Scientist. Sta. 1: Cruise Mid-2, Rep. 1, 03 Aug 1984, 38°36.12′N, 72°53.06′W, 2209 m (1, USNM 1661504 ) ; Rep. 3, 03 Aug 1984, 38°36.21′N, 72°52.96′W, 2179 m (1, USNM 1661505 ) ; Cruise Mid-4, Rep. 3, 17 May 1985, 38°35.88′N, 72°53.13′W, 2195 m (2, USNM 1661506 ) ; Cruise Mid-5, Rep. 1, 05 Aug 1985, 38°35.91′N, 72°53.10′W, 2185 m (3, USNM 1661507 ) ; Rep. 3, 05 Aug 1985, 38°35.90′N, 72°53.11′W, 2185 m (5, USNM 1661508 ) . Sta. 2: Cruise Mid-1, Rep. 2, 01 Apr 1984, 38°35.71′N, 72°53.69′W, 2018 m (2, USNM 1661509 ) ; Rep. 3, 01 Apr 1984, 38°35.71′N, 72°53.61′W, 2033 m (2, USNM 1661510 ) ; Cruise Mid-2, Rep. 3, 03 Aug 1984, 38°35.76′N, 72°53.81′W, 2004 m (3, USNM 1661511 ) ; Cruise Mid-3, Rep. 2, 02 Dec 1984, 38°35.75′N, 72°53.67′W, 2010 m (1, USNM 1661512 ) ; Rep. 3, 02 Dec 1984, 38°35.68′N, 72°53.69′W, 2015 m (1, USNM 16615013 ) ; Cruise Mid 6, Rep. 1, 13 Nov 1985, 38°35.66′N, 72°53.71′W, 2064 m (2, USNM 1661514 ) . Sta. 3: Cruise Mid-1, Rep. 2, 05 May 1984, 38°36.88′N, 72°51.34′W, 2055 m (1, USNM 1661515 ) ; Cruise Mid-2, Rep. 2, 03 Aug 1984, 38°36.87′N, 72°51.45′W, 2049 m (2, USNM 1661516 ) ; Cruise Mid-3, Rep. 2, 03 Dec 1984, 38°36.91′N, 72°51.55′W, 2050 m (2, USNM 1661517 ) ; Cruise Mid-6, Rep. 2, 12 Nov 1985, 38°36.75′N, 72°51.61′W, 2064 m (1, USNM 1661518 ) . Sta. 4: Rep. 2, 01 Aug 1984, 38°44.53′N, 72°41.23′W, 2106 m (1, USNM 1661519 ) ; Cruise Mid-3, Rep. 3, 05 Dec 1984, 38°44.40′N, 72°41.08′W, 2105 m (1, USNM 1661520 ) ; Cruise Mid-5: Cruise Rep. 2, 03 Aug 1985, 38°44.44′N, 72°41.22′W, 2095 m (2, USNM 1661521 ) . Sta. 5: Cruise Mid-1, Rep. 2, 04 May 1984, 38°50.53′N, 72°33.10′W, 2065 m (1, USNM 1661522 ) ; Rep. 3, 08 May 1984, 38°50.46′N, 72°33.14′W, 2080 m (1, USNM 16615023 ) ; Cruise Mid-2, Rep. 1, 01 Aug 1984, 38°50.42′N, 72°33.03′W, 2089 m (1, USNM 1661524 ) ; Rep. 3, 01 Aug 1984, 38°50.52′N, 72°32.96′W, 2074 m (2, USNM 16615025 ) ; Cruise Mid-3, Rep. 2; 05 Dec 1984, 38°50.40′N, 72°33.12′W, 2090 m (1, USNM 1661526 ) ; Rep. 3; 05 Dec 1984, 38°50.40′N, 72°33.12′W, 2090 m (1, USNM 01661527 ) ; Cruise Mid-4, Rep. 1, 16 May 1985, 38°50.46′N, 72°33.23′W, 2080 m (3, USNM 1661528 ) ; Rep. 2, 16 May 1985, 39°05.66′N, 72°03.25′W, 2045 m (1, USNM 16615029 ) ; Rep. 3, 16 May 1985, 38°50.46′N, 72°33.21′W, 2075 m (5, USNM 01661530 ) ; Cruise Mid-5, Rep. 1, 03 Aug 1985, 38°50.44′N, 72°33.18′W, 2077 m (1, USNM 1661531 ) ; Rep. 2, 03 Aug 1985, 38°50.44′N, 72°33.18′W, 2077 m (1, USNM 1661532 ) . Sta. 6: Cruise Mid-1, Rep. 1, 03 May 1984, 39°05.61′N, 72°02.98′W, 2090 m (2, USNM 1661533 ) ; Rep. 2, 03 May 1984, 39°05.63′N, 72°03.00′W, 2088 m (3, USNM 1661534 ) ; Rep. 3, 03 May, 1984, 39°05.59′N, 72°03.00′W, 2090 m (1, USNM 1661535 ) ; Cruise Mid-2, Rep. 1, 01 Aug 1988, 39°05.65′N, 72°02.97′W, 2084 m (1, USNM 1661536 ) ; Rep. 2, 01 Aug 1984, 39°05.68′N, 72°02.99′W, 2084 m (2, USNM 1661537 ) ; Cruise Mid-3, Rep. 1, 28 Nov 1984, 39°05.58′N, 72°02.81′W, 2090 m (2, USNM 1661538 ) ; Cruise Mid 4, Rep. 3, 15 May 1985, 39°05.65′N, 72°03.22′W, 2085 m (2, USNM 1661539 ) ; Cruise Mid-6, Rep. 1, 10 Nov 1985, 39°05.67′N, 72°03.36′W, 2089 m (2, USNM 1661540 ) . Sta. 7: Cruise Mid-1, Rep. 1, 03 May 1984, 38°27.32′N, 73°03.45′W, 2110 m (2, USNM 1661541 ) ; Rep. 2, 06 May 1984, 38°27.30′N, 73°03.43′W, 2100 m (1, USNM 1661542 ) ; Cruise Mid-3, Rep. 2, 02 Dec 1984, 38°27.31′N, 73°03.44′W, 2110 m (1, USNM 1661543 ) ; Rep. 3, 02 Aug 1984, 38°27.25′N, 73°03.44′W, 2100 m (3, USNM 1661544 ) ; Cruise Mid-4, Rep. 1, 18 May 1985, 38°27.26′N, 73°03.55′W, 2100 m (7, USNM 1661545 ) ; Rep. 2, 18 May 1986, 38°27.27′N, 73°03.52′W, 2105 m (3, USNM 1661546 ) , Cruise Mid-6, Rep. 1, 14 Nov 1984, 38°27.29′N, 73°03.58′W, 2096 m (3, USNM 1661547 ) . Sta. 8: Cruise Mid-1, Rep. 1, 06 May 1984, 38°27.36′N, 73°05.09′W, 2148 m (2, USNM 1661548 ) ; Rep. 2, 06 May 1984, 38°27.36′N, 73°04.88′W, 2150 m (4, USNM 1661549 ) ; Rep. 3, 06 May 1984, 38°27.36′N, 73°04.81′W, 2150 m (1, USNM 1661550 ) ; Cruise Mid-3, Rep. 2, 01 Dec 1984, 38°27.13′N, 73°04.87′W, 2150 m (1, USNM 1661551 ) ; Rep. 3, 01 Dec 1984, 38°27.30′N, 73°04.79′W, 2155 m (2, USNM 1661552 ) . Sta. 9: Cruise Mid-1, Rep. 3, 06 May 1984, 38°17.23′N, 73°14.60W, 2108 m (1, USNM 1661553 ) ; Cruise Mid-2, Rep. 2, 06 Aug 1984, 38°17.26′N, 73°14.49′W, 2114 m (1, USNM 1661554 ) ; Cruise Mid-3, Rep. 1, 30 Nov 1984, 38°17.20′N, 73°14.38′W, 2110 m (1, USNM 1661555 ) ; Rep. 3, 30 Nov 1984, 38°17.20′N, 73°14.47′W, 2105 m (8, USNM 1661556 ) ; Cruise Mid-4, Rep. 3, 18 May 1985, 38°17.24′N, 73°14.62′W, 2100 m (3, USNM 166157 ) . Cruise Mid-6, Rep. 2, 17 Nov 1985, 38°17.28′N, 73°14.65′W, 2104 m (6, USNM 1661558 ) . Sta. 10: Cruise Mid-1, Rep. 3, 07 May 1984, 37°51.83′N, 73°19.94′W, 2095 m (1, USNM 1661559 ) ; Cruise Mid-3, Rep. 3, 30 Nov 1984, 37°51.80′N, 73°19.85′W, 2100 m (5, USNM 1661560 ) ; Cruise Mid-4, Rep. 1, 19 May 1985, 37°51.76′N, 72°20.01′W, 2095 m (5, USNM 1661561 ) ; Rep. 3, 19 May 1985, 37°51.73′N, 73°20.01′W, 2095 m (2, USNM 1661562 ) . Sta. 11: Cruise Mid-2, Rep. 3, 05 Aug 1984, 38°40.25′N, 72°56.24′W, 1504 m (1, USNM 1661563 ) ; Cruise Mid-6, Rep. 3, 13 Nov 1985, 38°40.06′N, 72°56.41′W, 1519 m (3, USNM 1661564 ) . Sta. 12: Cruise Mid-1, Rep. 1, 07 May 1984, 38°29.34′N, 72°42.23′W, 2501 m (3, USNM 1661565 ) ; Rep. 2, 07 May 1984, 38°29.33′N, 72°42.19′W, 2500 m (3, USNM 1661566 ) ; Rep. 3, 08 May 1984, 38°29.33′N, 72°42.24′W, 2500 m (1, USNM 16615676 ) ; Cruise Mid-2, Rep. 2, 05 Aug 1984, 38°29.39′N, 72°42.01′W, 2504 m (1, USNM 1661568 ) ; Cruise Mid-3, Rep. 2, 03 Dec 1984, 38°29.22′N, 72°42.13′W, 2505 m (1, USNM 1661569 ) ; Cruise Mid-4, Rep. 2, 18 May 1985, 38°29.22′N, 72°42.17′W, 2505 m (5, USNM 1661570 ) ; Cruise Mid-6, Rep. 2, 14 Nov 1985, 38°29.20′N, 72°42.29′W, 2504 m (1, USNM 1661571 ) .— Off New Jersey, U.S. EPA DWD-106 Site Survey, R. Petrecca, Chief Scientist. Sta. F: Rep. 1, 18 Nov 1985, 38°51.10′N, 72°16.39′W, 2500 m (2, MCZ 161956 ) ; Rep. 2, 18 Nov 1985, 38°51.12′N, 72°16.32′W, 2500 m (7, MCZ 161957 ) ; Rep. 3, 18 Nov 1985, 38°51.11′N, 72°16.39′W, 2500 m (1, MCZ 161958 ) . Sta. G: Rep. 1, 18 Nov 1985, 38°55.66′N, 72°02.53′W, 2505 m (5, MCZ 161959 ) ; Rep. 2, 18 Nov 1985, 38°55.63′N, 72°02.54′W, 2509 m (2, MCZ 161960 ) ; Rep. 3, 18 Nov 1985, 38°55.60′N, 72°02.54′W, 2505 m (7, MCZ 161961 ) .— Off the Cape Lookout , North Carolina, US South Atlantic ACSAR Program , coll. J.A. Blake, Chief Scientist. Sta. 7: Cruise SA-2, Rep. 1, 21 May 1984, 33°58.30′N, 74°56.20′W, 3494 m (1, USNM 1661572 ) .

Description. An elongate narrow species with middle segments often expanded due to enlarged stomach area. Holotype complete with 55 setigers, 7.7 mm long and ca. 0.4 mm wide across anterior setigers ( Fig. 40A ); some paratypes larger, with ca. 60 setigers, up to 8.2 mm long. Body generally cylindrical in cross section but dorsal and ventral surfaces generally only weakly elevated; dorsal and ventral grooves absent. Body gradually narrowing posteriorly towards pygidium ( Fig. 40A, D ). Anterior and middle segments short, crowded, about five times wider than long ( Fig. 39A–B ); these transitioning to spine-bearing segments about as wide as long, becoming moniliform with deep cinctures, each about 1.5 times as wide as long ( Fig. 40D ). Some specimens with several expanded segments together forming a bulge in mid-body segments ( Fig. 40A ). This “stomach” usually filled with ingested sediment and prominent in a few specimens, not apparent in others. Color in alcohol light tan with no distinctive pigmentation.

Pre-setiger region about as long as first seven setigers, tapering anteriorly ( Figs. 39A–B , 40B, E ). Prostomium triangular, elongate, tapering to narrow tip ( Fig. 39A ); eyespots absent; nuchal organs narrow curved grooves on posterior lateral margin ( Figs. 39B ). Peristomium with two separate rings separated by groove, best developed dorsally ( Figs. 39A–B , 40C ); anterior ring smooth; second ring with dorsal tentacles near anterior border followed by first pair of branchiae posterior to tentacles ( Figs. 39A–B , 40C ). First setiger merged entirely with peristomium along anterior margin, bearing second pair of branchiae dorsal to notosetae ( Fig. 39A–B ); subsequent branchiae in similar location dorsal to notosetae. Branchiae thin, elongate, continuing along body to posterior setigers.

Parapodia of anterior and middle segments reduced to low ridges or mounds from which setae arise; posterior parapodia becoming moniliform, modified with deep intersegmental notches producing cinctured segments with parapodia becoming elevated and bearing thin membranes from which setae arise ( Fig. 40D, F ). Anterior setae all long capillaries numbering about 10–12 per fascicle, including long natatory-like setae in some notopodia of anterior and middle segments ( Fig. 40A ); these not associated with sexual maturity. Notopodial acicular spines from setigers 29–32 (holotype 29); neuropodial spines from setigers 25–27 (holotype 26). Spines numbering 1–3 initially, then increasing to 9–11 in notopodia and 14–15 in neuropodia; with full cinctures having up to 23–26 spines on a side ( Fig. 40F ). Spines alternating with thin, sharply pointed spinous capillaries slightly longer than spines ( Fig. 40F–G ). Cinctures with narrow dorsal, lateral, and ventral gaps between noto- and neuropodial fascicles providing a prominent armature encircling posterior segments ( Fig. 40F ). Individual spines with basal manubrium at emergence from podial lobes; spines only weakly curved, tapering to narrow pointed tip; blade appearing fusiform in some views ( Fig. 40G–I ).

Body terminating in short narrow pygidium bearing an elongate semicircular disk ( Fig. 40D ).

Methyl green staining. Posterior part of prostomium retaining MG stain, otherwise no pattern.

Remarks. Chaetozone profunda n. sp. is the third species of the genus reported to have the peristomium divided into two rings, with the large posterior ring including an achaetous segment that merges seamlessly with setiger 1; the dorsal tentacles arise from the anterior half of the second ring instead of near the posterior margin as in most Chaetozone species; first branchiae are located immediately posterior to the dorsal tentacles and the second pair arise on the merged setiger 1 in a line from the dorsal tentacles and first branchiae. The two previously described species having these characteristics, both from the Antarctic seas, are C. australosetosa Blake 2018 and C. biannulata Blake, 2018 . Chaetozone profunda n. sp. most closely resembles C. biannulata in having a long narrow pre-setiger region with a pointed prostomium. In addition, both species are of a similar size and have 55–60 setigers. Chaetozone profunda n. sp. differs from C. biannulata in having the first peristomial ring distinctly separated from the prostomium instead of merged or only weakly separated and lacking instead of having a peristomial dorsal crest. In C. profunda n. sp. the neuropodial acicular spines are first present from setigers 25–27, whereas in C. biannulata , the neuropodial spines are first present from setigers 37–38. The number of spines in posterior cinctures are similar, with C. profunda n. sp. having 20–24 spines on side and C. biannulata having 23–26.

Locally, Chaetozone profunda n. sp. can be easily distinguished from its congeners by the long, narrow presetiger region terminating in a narrow pointed prostomium, dorsal tentacles arising from the second peristomial ring well anterior to setiger 1, and with full cinctures of acicular spines and moniliform cinctured segments appearing in the second half of the body. A few specimens were observed with an expanded “stomach” filled with fine sediment particles in a few segments in middle body segments, but most specimens lacked this feature.

Biology. A deep-water species, Chaetozone profunda n. sp. occurs in sediments having relatively high silt + clay inventories. However, North Atlantic Station 8, where the holotype and several paratypes were collected, is at the base of Lydonia Canyon where the sediments consisted of approximately 50% fine sands in addition to silt and clay (Maciolek et. al. 1987b). In contrast, the Mid-Atlantic stations had lower sand inventories (ca. 15%) and higher percentages of silt + clay.

Etymology. The epithet is from the Latin, profundus for deep or vast, referring to the deep-sea habitat of this species.

Distribution. U.S. Atlantic continental slope: Northeastern slope, 1338–2184 m; Mid-Atlantic slope, 1519– 2509 m; U.S. South Atlantic slope, 3494 m.

Figures

FIGURE 39. Chaetozone profunda n. sp. A, anterior end, dorsal view; B, anterior end, left lateral view. A: paratype (USNM 1661502); B: USNM (USNM 1661539).

FIGURE 40. Chaetozone profunda n. sp. A, entire worm, left lateral view; B, anterior end, right lateral view; C, anterior end, dorsal view; D, posterior end, dorsal view; E, anterior end, right lateral view; F, posterior parapodium with acicular spines and capillaries, anterior view; G, notoacicular spines and capillaries from (F); H, neuroacicular spines and capillaries from (F); I, detail of neuroacicular spines and capillary from (H).A, D–E holotype (USNM 1661492); B, paratype (USNM 1661497); C, paratype USNM 1661494); F–I, paratype (USNM 1661495).