New species and records of Caulleriella, Chaetocirratulus and Chaetozone (Annelida, Cirratulidae) from continental shelf and slope depths of the Western North Atlantic Ocean Author Blake, James A. 0000-0001-8217-9769 jablake9@gmail.com text Zootaxa 2022 2022-03-09 5113 1 1 89 http://zoobank.org/eb01c862-025e-493f-8ca9-934b4f1626af journal article 112028 10.11646/zootaxa.5113.1.1 8b4b0886-ef22-452d-8be4-31089686eeb2 1175-5326 6340998 EB01C862-025E-493F-8CA9-934B4F1626AF Chaetocirratulus sandersi new species Figures 10–11 urn:lsid:zoobank.org:act: B641B107-211D-4486-8C92-8A6710D46B48 Chaetozone sp. B : Maciolek et al. 1987a : D-2 (in part). Material examined . Off New Jersey and Delaware , U.S. Mid-Atlantic ACSAR Program, coll. R. Petrecca , Chief Scientist. Sta. 2A : Cruise Mid-1, Leg 1, R/ V Cape Hatteras , 01 Apr 1984 , 38°35.78ʹN , 72°53.656ʹW , 2013 m , holotype ( USNM 1660938 ) . Description . A moderately large species, holotype complete but damaged, 18 mm long, 3.5 mm wide across anterior setigers, with ca. 80 setigers; middle body segments about 4.5 mm wide, then narrowing to posterior end. Specimen partially damaged between setigers 19–20, distorting overall shape, but both sections remain joined ( Fig. 11A ). Body fusiform, widest in middle segments, with narrow crowded segments ( Figs. 10A–B , 11A ). Parapodia lateral with dorsal and ventral surfaces broad, with distinct intersegmental grooves across both surfaces ( Fig. 10A– B ). Dorsum elevated with distinct mid-dorsal groove ( Fig. 10A ), deepest along anterior segments, less prominent in middle and posterior segments; venter also elevated, but not as high, also with mid-ventral groove along anterior segments, with narrow ridge in groove ( Fig. 10B ). Middle and posterior segments lacking ventral groove. Color in alcohol light tan; venter of peristomium with a few minute scattered pigment spots. Pre-setiger region broadly triangular, wider than long, about as long as first five setigers ( Figs. 10A–B , 11A ). Prostomium short, wedge-shaped, narrowing to rounded anterior margin ( Fig. 10A–D ); eyespots absent; nuchal organs narrow slits at posterior lateral margins. Peristomium with two rings, first largest with several transverse grooves or slits; dorsally surrounding posterior prostomium ( Fig. 10A, C ); ventrally forming large lip around mouth ( Fig. 10 B, D ); second ring narrower, dorsally bearing a pair of dorsal tentacles and first branchiae lateral to tentacles ( Fig. 10A, C ). Subsequent branchiae on setigers dorsal to notosetae. Most branchiae missing; a few short narrow filamentous branchiae retained in middle segments. Parapodia well-developed along entire body, with those of first 20 anterior setigers largest and most prominent ( Fig. 10A–C ); noto- and neuropodia distinct ridges from which setae arise; separate postsetal lamellae not present. Setae include long, smooth capillaries and acicular spines. Capillaries numbering 9–10 per noto- and neuropodia in anterior setigers, reduced to 5–6 in middle segments and 1–3 in posterior setigers. Some capillaries with thicker shafts transitioning to acicular spines in mid-body at about setigers 27 (neuropodia) and 31 (notopodia). Individual spines with straight, not sigmoid, shafts and narrow rounded tips ( Fig. 11C–D ). Spines 1–2 per notopodium and 2–3 per neuropodium, accompanied by 1–3 capillaries. Pygidium with a simple rounded, terminal lobe ventral to anal opening ( Fig. 11B ). Methyl green staining . Methyl green stains the pre-setiger region heavily on both sides ( Fig. 10C–D ), continuing on the parapodia and producing transverse bands across the venter of anterior setigers ( Fig. 10D ); dorsal tentacles and branchiae not staining. FIGURE 10 . Chaetocirratulus sandersi n. sp . Holotype (USNM 1660938): A, anterior end, dorsal view; B, anterior end, ventral view; C, anterior end, dorsal view; D, same, ventral view. A–B, stained with Shirlastain A; C–D stained with MG. FIGURE 11 . Chaetocirratulus sandersi n. sp . Holotype (USNM 1660938): A, anterior and middle sections of body in dorsal view showing damaged section; B, posterior end, dorsal view; C, two acicular spines and one capillary from posterior neuropodium; D, detail of neuropodial acicular spine. A–B stained with Shirlastain A. Remarks . Among four species of Chaetocirratulus reported in this study from the U.S. Atlantic continental slope, C. sandersi n. sp . is the only one to have two peristomial rings instead of three. These are complete both dorsally and ventrally. No body pigment is present and there are distinct mid-dorsal and ventral grooves, the latter of which has a medial ridge. The morphology of the four species is compared in Table 2 . Etymology . This species is named for the late Dr. Howard Sanders, prominent ecologist whose classic studies with the late Dr. Robert Hessler on the North Atlantic deep-sea benthos introduced us to the undiscovered richness of deep-sea benthic infauna. Distribution . Off New Jersey and Delaware , continental slope, 2013 m .